bsd-thread-time-example/main.cpp
Harald Eilertsen 45e6aebfbf A simple app to get run times from a thread
Just a quick app to test and demonstrate how to get run times from a
specific thread on FreeBSD.
2025-06-20 13:21:43 +02:00

98 lines
2.5 KiB
C++

/*
* SPDX-FileCopyrightText: 2025 Eilertsens Kodeknekkeri
* SPDX-FileCopyrightText: 2025 The FreeBSD Foundation
* SPDX-FileContributor: Harald Eilertsen <haraldei@anduin.net>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "helpers.hpp"
#include "fast_cpu_time.hpp"
#include "procstat_cpu_time.hpp"
#include "sysctl_cpu_time.hpp"
#include <cassert>
#include <iostream>
#include <pthread.h>
#include <pthread_np.h>
#include <sys/resource.h>
#include <unistd.h>
pid_t ktid; // Kernel thread id,
/*
* A simple thread.
*
* As we're only interested in observing the thread from another thread, it's
* not important what it does, only that it stays around for long enough that
* we can make our observations.
*/
void * thread_start(void * arg) {
// Get the kernel thread id for the thread and save it
// so it's accessible to the main thread.
ktid = pthread_getthreadid_np();
for (auto i = 0; i < 5; ++i) {
sleep(1);
std::cout << ".";
}
/*
* We can use getrusage(2) to quickly obtain the running time for
* the current thread. This does not seem to be exposed for other
* threads.
*/
auto ru = new struct rusage{};
getrusage(RUSAGE_THREAD, ru);
std::cout << " done!" << std::endl;
return ru;
}
int main(int argc, char * argv[]) {
std::cout << "Hello Victims!" << std::endl;
pthread_t thread;
auto res = pthread_create(&thread, nullptr, thread_start, nullptr);
assert(res == 0);
#ifndef NDEBUG
std::cout << "[*] thread = " << thread << ", "
<< "kernel tid = " << ktid
<< std::endl;
#endif
sleep(2);
auto fast_time = fast_thread_cpu_time(thread);
struct timeval procstat_user_time;
struct timeval procstat_sys_time;
procstat_cpu_time(thread, &procstat_user_time, &procstat_sys_time);
struct timeval sysctl_user_time;
struct timeval sysctl_sys_time;
sysctl_cpu_time(thread, &sysctl_user_time, &sysctl_sys_time);
void * thread_res;
auto join_res = pthread_join(thread, &thread_res);
assert(join_res == 0);
std::cout << "Fast time: " << fast_time << "\n";
std::cout << "Procstat:"
<< " User time: " << timeval_to_long(procstat_user_time) << ", "
<< " Sys time : " << timeval_to_long(procstat_sys_time) << "\n";
std::cout << "Sysctl :"
<< " User time: " << timeval_to_long(sysctl_user_time) << ", "
<< " Sys time : " << timeval_to_long(sysctl_sys_time) << "\n";
auto ru = reinterpret_cast<struct rusage *>(thread_res);
std::cout << "Rusage :"
<< " User time: " << timeval_to_long(ru->ru_utime) << ", "
<< " Sys time : " << timeval_to_long(ru->ru_stime) << "\n";
}