ladybird/Kernel/PerformanceEventBuffer.h
Andreas Kling 5dafb72370 Kernel+Profiler: Make profiling per-process and without core dumps
This patch merges the profiling functionality in the kernel with the
performance events mechanism. A profiler sample is now just another
perf event, rather than a dedicated thing.

Since perf events were already per-process, this now makes profiling
per-process as well.

Processes with perf events would already write out a perfcore.PID file
to the current directory on death, but since we may want to profile
a process and then let it continue running, recorded perf events can
now be accessed at any time via /proc/PID/perf_events.

This patch also adds information about process memory regions to the
perfcore JSON format. This removes the need to supply a core dump to
the Profiler app for symbolication, and so the "profiler coredump"
mechanism is removed entirely.

There's still a hard limit of 4MB worth of perf events per process,
so this is by no means a perfect final design, but it's a nice step
forward for both simplicity and stability.

Fixes #4848
Fixes #4849
2021-01-11 11:36:00 +01:00

92 lines
2.7 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <Kernel/KBuffer.h>
#include <Kernel/KResult.h>
namespace Kernel {
class KBufferBuilder;
struct [[gnu::packed]] MallocPerformanceEvent {
size_t size;
FlatPtr ptr;
};
struct [[gnu::packed]] FreePerformanceEvent {
size_t size;
FlatPtr ptr;
};
struct [[gnu::packed]] PerformanceEvent {
u8 type { 0 };
u8 stack_size { 0 };
u32 tid { 0 };
u64 timestamp;
union {
MallocPerformanceEvent malloc;
FreePerformanceEvent free;
} data;
static constexpr size_t max_stack_frame_count = 32;
FlatPtr stack[max_stack_frame_count];
};
class PerformanceEventBuffer {
public:
PerformanceEventBuffer();
KResult append(int type, FlatPtr arg1, FlatPtr arg2);
void clear()
{
m_count = 0;
}
size_t capacity() const
{
if (!m_buffer)
return 0;
return m_buffer->size() / sizeof(PerformanceEvent);
}
size_t count() const { return m_count; }
const PerformanceEvent& at(size_t index) const
{
return const_cast<PerformanceEventBuffer&>(*this).at(index);
}
OwnPtr<KBuffer> to_json(ProcessID, const String& executable_path) const;
bool to_json(KBufferBuilder&, ProcessID, const String& executable_path) const;
private:
PerformanceEvent& at(size_t index);
size_t m_count { 0 };
OwnPtr<KBuffer> m_buffer;
};
}