ladybird/Userland/Utilities/pidof.cpp
Tom 7e77a2ec40 Everywhere: Improve CPU usage calculation
As threads come and go, we can't simply account for how many time
slices the threads at any given point may have been using. We need to
also account for threads that have since disappeared. This means we
also need to track how many time slices we have expired globally.

However, because this doesn't account for context switches outside of
the system timer tick values may still be under-reported. To solve this
we will need to track more accurate time information on each context
switch.

This also fixes top's cpu usage calculation which was still based on
the number of context switches.

Fixes #6473
2021-07-18 22:08:26 +02:00

69 lines
2 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/String.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/ProcessStatisticsReader.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static int pid_of(const String& process_name, bool single_shot, bool omit_pid, pid_t pid)
{
bool displayed_at_least_one = false;
auto all_processes = Core::ProcessStatisticsReader::get_all();
if (!all_processes.has_value())
return 1;
for (auto& it : all_processes.value().processes) {
if (it.name == process_name) {
if (!omit_pid || it.pid != pid) {
out(displayed_at_least_one ? " {}" : "{}", it.pid);
displayed_at_least_one = true;
if (single_shot)
break;
}
}
}
if (displayed_at_least_one)
outln();
return 0;
}
int main(int argc, char** argv)
{
bool single_shot = false;
const char* omit_pid_value = nullptr;
const char* process_name = nullptr;
Core::ArgsParser args_parser;
args_parser.add_option(single_shot, "Only return one pid", nullptr, 's');
args_parser.add_option(omit_pid_value, "Omit the given PID, or the parent process if the special value %PPID is passed", nullptr, 'o', "pid");
args_parser.add_positional_argument(process_name, "Process name to search for", "process-name");
args_parser.parse(argc, argv);
pid_t pid_to_omit = 0;
if (omit_pid_value) {
if (!strcmp(omit_pid_value, "%PPID")) {
pid_to_omit = getppid();
} else {
auto number = StringView(omit_pid_value).to_uint();
if (!number.has_value()) {
warnln("Invalid value for -o");
args_parser.print_usage(stderr, argv[0]);
return 1;
}
pid_to_omit = number.value();
}
}
return pid_of(process_name, single_shot, omit_pid_value != nullptr, pid_to_omit);
}