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ladybird/Kernel/Time/HPETComparator.cpp

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Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
/*
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 08:24:48 +00:00
* SPDX-License-Identifier: BSD-2-Clause
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
*/
#include <Kernel/Assertions.h>
Meta: Split debug defines into multiple headers. The following script was used to make these changes: #!/bin/bash set -e tmp=$(mktemp -d) echo "tmp=$tmp" find Kernel \( -name '*.cpp' -o -name '*.h' \) | sort > $tmp/Kernel.files find . \( -path ./Toolchain -prune -o -path ./Build -prune -o -path ./Kernel -prune \) -o \( -name '*.cpp' -o -name '*.h' \) -print | sort > $tmp/EverythingExceptKernel.files cat $tmp/Kernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/Kernel.macros cat $tmp/EverythingExceptKernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/EverythingExceptKernel.macros comm -23 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/Kernel.unique comm -1 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/EverythingExceptKernel.unique cat $tmp/Kernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/Kernel.header cat $tmp/EverythingExceptKernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/EverythingExceptKernel.header for macro in $(cat $tmp/Kernel.unique) do cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.new-includes ||: done cat $tmp/Kernel.new-includes | sort > $tmp/Kernel.new-includes.sorted for macro in $(cat $tmp/EverythingExceptKernel.unique) do cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.old-includes ||: done cat $tmp/Kernel.old-includes | sort > $tmp/Kernel.old-includes.sorted comm -23 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.new comm -13 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.old comm -12 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.mixed for file in $(cat $tmp/Kernel.includes.new) do sed -i -E 's/#include <AK\/Debug\.h>/#include <Kernel\/Debug\.h>/' $file done for file in $(cat $tmp/Kernel.includes.mixed) do echo "mixed include in $file, requires manual editing." done
2021-01-25 15:07:10 +00:00
#include <Kernel/Debug.h>
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
#include <Kernel/Time/HPETComparator.h>
#include <Kernel/Time/TimeManagement.h>
namespace Kernel {
Kernel: Fix issues supporting HPETs with 32-bit-only main counter If the HPET main counter does not support full 64 bits, we should not expect the upper 32 bit to work. This is a problem when writing to the upper 32 bit of the comparator value, which requires the TimerConfiguration::ValueSet bit to be set, but if it's not 64 bit capable then the bit will not be cleared and leave it in a bad state. Fixes #6990
2021-05-12 03:20:06 +00:00
UNMAP_AFTER_INIT NonnullRefPtr<HPETComparator> HPETComparator::create(u8 number, u8 irq, bool periodic_capable, bool is_64bit_capable)
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
{
Kernel: Fix issues supporting HPETs with 32-bit-only main counter If the HPET main counter does not support full 64 bits, we should not expect the upper 32 bit to work. This is a problem when writing to the upper 32 bit of the comparator value, which requires the TimerConfiguration::ValueSet bit to be set, but if it's not 64 bit capable then the bit will not be cleared and leave it in a bad state. Fixes #6990
2021-05-12 03:20:06 +00:00
auto timer = adopt_ref(*new HPETComparator(number, irq, periodic_capable, is_64bit_capable));
Kernel: Fix GenericInterruptHandler problems with virtual functions Because registering and unregistering interrupt handlers triggers calls to virtual functions, we can't do this in the constructor and destructor. Fixes #5539
2021-02-27 00:17:57 +00:00
timer->register_interrupt_handler();
return timer;
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
}
Kernel: Fix issues supporting HPETs with 32-bit-only main counter If the HPET main counter does not support full 64 bits, we should not expect the upper 32 bit to work. This is a problem when writing to the upper 32 bit of the comparator value, which requires the TimerConfiguration::ValueSet bit to be set, but if it's not 64 bit capable then the bit will not be cleared and leave it in a bad state. Fixes #6990
2021-05-12 03:20:06 +00:00
UNMAP_AFTER_INIT HPETComparator::HPETComparator(u8 number, u8 irq, bool periodic_capable, bool is_64bit_capable)
Kernel: Remove "stale callback" concept from time management If a hardware timer doesn't have a callback registered, it's now simply represented by a null m_callback.
2020-04-16 16:20:27 +00:00
: HardwareTimer(irq)
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
, m_periodic(false)
, m_periodic_capable(periodic_capable)
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
, m_enabled(false)
Kernel: Fix issues supporting HPETs with 32-bit-only main counter If the HPET main counter does not support full 64 bits, we should not expect the upper 32 bit to work. This is a problem when writing to the upper 32 bit of the comparator value, which requires the TimerConfiguration::ValueSet bit to be set, but if it's not 64 bit capable then the bit will not be cleared and leave it in a bad state. Fixes #6990
2021-05-12 03:20:06 +00:00
, m_is_64bit_capable(is_64bit_capable)
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
, m_comparator_number(number)
{
}
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
void HPETComparator::disable()
{
if (!m_enabled)
return;
m_enabled = false;
HPET::the().disable(*this);
}
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
void HPETComparator::set_periodic()
{
Everywhere: Rename ASSERT => VERIFY (...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
2021-02-23 19:42:32 +00:00
VERIFY(m_periodic_capable);
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
m_periodic = true;
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
m_enabled = true;
Kernel: Fix HPET timer not firing in Bochs * Change the register structures to use the volatile keyword explicitly on the register values. This avoids accidentally omitting it as any access will be guaranteed volatile. * Don't assume we can read/write 64 bit value to the main counter and the comparator. Not all HPET implementations may support this. So, just use 32 bit words to access the registers. This ultimately works around a bug in Bochs 2.6.11 that loses 32 bits of a 64 bit write to a timer's comparator register (it internally writes one half and clears the Tn_VAL_SET_CNF bit, and then because it's cleared it fails to write the second half). * Properly calculate the tick duration in calculate_ticks_in_nanoseconds * As per specification, changing the frequency of one periodic timer requires a restart of all periodic timers as it requires the main counter to be reset.
2020-11-03 20:19:42 +00:00
HPET::the().enable_periodic_interrupt(*this);
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
}
void HPETComparator::set_non_periodic()
{
Everywhere: Rename ASSERT => VERIFY (...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
2021-02-23 19:42:32 +00:00
VERIFY(m_periodic_capable);
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
m_periodic = false;
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
m_enabled = true;
Kernel: Fix HPET timer not firing in Bochs * Change the register structures to use the volatile keyword explicitly on the register values. This avoids accidentally omitting it as any access will be guaranteed volatile. * Don't assume we can read/write 64 bit value to the main counter and the comparator. Not all HPET implementations may support this. So, just use 32 bit words to access the registers. This ultimately works around a bug in Bochs 2.6.11 that loses 32 bits of a 64 bit write to a timer's comparator register (it internally writes one half and clears the Tn_VAL_SET_CNF bit, and then because it's cleared it fails to write the second half). * Properly calculate the tick duration in calculate_ticks_in_nanoseconds * As per specification, changing the frequency of one periodic timer requires a restart of all periodic timers as it requires the main counter to be reset.
2020-11-03 20:19:42 +00:00
HPET::the().disable_periodic_interrupt(*this);
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
}
void HPETComparator::handle_irq(const RegisterState& regs)
{
HardwareTimer::handle_irq(regs);
if (!is_periodic())
set_new_countdown();
}
void HPETComparator::set_new_countdown()
{
Everywhere: Rename ASSERT => VERIFY (...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
2021-02-23 19:42:32 +00:00
VERIFY_INTERRUPTS_DISABLED();
VERIFY(m_frequency <= HPET::the().frequency());
Kernel: Fix HPET timer not firing in Bochs * Change the register structures to use the volatile keyword explicitly on the register values. This avoids accidentally omitting it as any access will be guaranteed volatile. * Don't assume we can read/write 64 bit value to the main counter and the comparator. Not all HPET implementations may support this. So, just use 32 bit words to access the registers. This ultimately works around a bug in Bochs 2.6.11 that loses 32 bits of a 64 bit write to a timer's comparator register (it internally writes one half and clears the Tn_VAL_SET_CNF bit, and then because it's cleared it fails to write the second half). * Properly calculate the tick duration in calculate_ticks_in_nanoseconds * As per specification, changing the frequency of one periodic timer requires a restart of all periodic timers as it requires the main counter to be reset.
2020-11-03 20:19:42 +00:00
HPET::the().update_non_periodic_comparator_value(*this);
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
}
size_t HPETComparator::ticks_per_second() const
{
return m_frequency;
}
void HPETComparator::reset_to_default_ticks_per_second()
{
Everywhere: Replace a bundle of dbg with dbgln. These changes are arbitrarily divided into multiple commits to make it easier to find potentially introduced bugs with git bisect.Everything: The modifications in this commit were automatically made using the following command: find . -name '*.cpp' -exec sed -i -E 's/dbg\(\) << ("[^"{]*");/dbgln\(\1\);/' {} \;
2021-01-09 17:51:44 +00:00
dbgln("reset_to_default_ticks_per_second");
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
m_frequency = OPTIMAL_TICKS_PER_SECOND_RATE;
if (!is_periodic())
set_new_countdown();
else
try_to_set_frequency(m_frequency);
}
bool HPETComparator::try_to_set_frequency(size_t frequency)
{
InterruptDisabler disabler;
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
if (!is_capable_of_frequency(frequency)) {
Everywhere: Replace a bundle of dbg with dbgln. These changes are arbitrarily divided into multiple commits to make it easier to find potentially introduced bugs with git bisect.Everything:
2021-01-10 15:21:56 +00:00
dbgln("HPETComparator: not cable of frequency: {}", frequency);
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
return false;
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
}
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
auto hpet_frequency = HPET::the().frequency();
Everywhere: Rename ASSERT => VERIFY (...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
2021-02-23 19:42:32 +00:00
VERIFY(frequency <= hpet_frequency);
Kernel: Fix HPET timer not firing in Bochs * Change the register structures to use the volatile keyword explicitly on the register values. This avoids accidentally omitting it as any access will be guaranteed volatile. * Don't assume we can read/write 64 bit value to the main counter and the comparator. Not all HPET implementations may support this. So, just use 32 bit words to access the registers. This ultimately works around a bug in Bochs 2.6.11 that loses 32 bits of a 64 bit write to a timer's comparator register (it internally writes one half and clears the Tn_VAL_SET_CNF bit, and then because it's cleared it fails to write the second half). * Properly calculate the tick duration in calculate_ticks_in_nanoseconds * As per specification, changing the frequency of one periodic timer requires a restart of all periodic timers as it requires the main counter to be reset.
2020-11-03 20:19:42 +00:00
m_frequency = frequency;
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
m_enabled = true;
Everywhere: Replace dbgln<flag>(...) with dbgln_if(flag, ...) Replacement made by `find Kernel Userland -name '*.h' -o -name '*.cpp' | sed -i -Ee 's/dbgln\b<(\w+)>\(/dbgln_if(\1, /g'`
2021-02-07 12:03:24 +00:00
dbgln_if(HPET_COMPARATOR_DEBUG, "HPET Comparator: Max frequency {} Hz, want to set {} Hz, periodic: {}", hpet_frequency, frequency, is_periodic());
Kernel: Fix HPET timer not firing in Bochs * Change the register structures to use the volatile keyword explicitly on the register values. This avoids accidentally omitting it as any access will be guaranteed volatile. * Don't assume we can read/write 64 bit value to the main counter and the comparator. Not all HPET implementations may support this. So, just use 32 bit words to access the registers. This ultimately works around a bug in Bochs 2.6.11 that loses 32 bits of a 64 bit write to a timer's comparator register (it internally writes one half and clears the Tn_VAL_SET_CNF bit, and then because it's cleared it fails to write the second half). * Properly calculate the tick duration in calculate_ticks_in_nanoseconds * As per specification, changing the frequency of one periodic timer requires a restart of all periodic timers as it requires the main counter to be reset.
2020-11-03 20:19:42 +00:00
if (is_periodic()) {
HPET::the().update_periodic_comparator_value();
} else {
HPET::the().update_non_periodic_comparator_value(*this);
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
}
Kernel: Set InterruptEnable on HPET Comparators when frequency is set This fixes non-periodic comparators not receiving interrupts, as we were never setting the InterruptEnable bit in their capabilities register (unlike periodic comparators's bit, which was set as a side effect of calling set_periodic on them to set their periodic bit). This should help getting profiling work on bare-metal SerenityOS installations, which were not guaranteed to have 2 periodic comparators available.
2021-05-17 16:23:04 +00:00
HPET::the().enable(*this);
Kernel: Fix HPET timer not firing in Bochs * Change the register structures to use the volatile keyword explicitly on the register values. This avoids accidentally omitting it as any access will be guaranteed volatile. * Don't assume we can read/write 64 bit value to the main counter and the comparator. Not all HPET implementations may support this. So, just use 32 bit words to access the registers. This ultimately works around a bug in Bochs 2.6.11 that loses 32 bits of a 64 bit write to a timer's comparator register (it internally writes one half and clears the Tn_VAL_SET_CNF bit, and then because it's cleared it fails to write the second half). * Properly calculate the tick duration in calculate_ticks_in_nanoseconds * As per specification, changing the frequency of one periodic timer requires a restart of all periodic timers as it requires the main counter to be reset.
2020-11-03 20:19:42 +00:00
enable_irq(); // Enable if we haven't already
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
return true;
}
bool HPETComparator::is_capable_of_frequency(size_t frequency) const
{
if (frequency > HPET::the().frequency())
return false;
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
// HPET::update_periodic_comparator_value and HPET::update_non_periodic_comparator_value
// calculate the best counter based on the desired frequency.
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
return true;
}
size_t HPETComparator::calculate_nearest_possible_frequency(size_t frequency) const
{
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
if (frequency > HPET::the().frequency())
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
return HPET::the().frequency();
Kernel: Improve time keeping and dramatically reduce interrupt load This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-04 05:12:50 +00:00
// HPET::update_periodic_comparator_value and HPET::update_non_periodic_comparator_value
// calculate the best counter based on the desired frequency.
return frequency;
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
}
Kernel: Fix APIC timer calibration to be more accurate We were calibrating it to 260 instead of 250 ticks per second (being off by one for the 1/10th second calibration time), resulting in ticks of only ~3.6 ms instead of ~4ms. This gets us closer to ~4ms, but because the APIC isn't nearly as precise as e.g. HPET, it will only be a best effort. Then, use the higher precision reference timer to more accurately calculate how many ticks we actually get each second. Also the frequency calculation was off, causing a "Frequency too slow" error with VMware. Fixes some problems observed in #5539
2021-02-28 18:47:03 +00:00
u64 HPETComparator::current_raw() const
{
return HPET::the().read_main_counter();
}
u64 HPETComparator::raw_to_ns(u64 raw_delta) const
{
return HPET::the().raw_counter_ticks_to_ns(raw_delta);
}
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
}
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