79 lines
2.0 KiB
C++
79 lines
2.0 KiB
C++
#include "pseudo_barrier.h"
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#include "thread.h"
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#include <atomic>
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#include <chrono>
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#include <cinttypes>
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#include <csignal>
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#include <cstdio>
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#include <cstdlib>
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#include <cstring>
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#include <mutex>
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#include <thread>
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#include <unistd.h>
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#include <vector>
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pseudo_barrier_t barrier;
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std::mutex print_mutex;
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std::atomic<bool> can_work = ATOMIC_VAR_INIT(false);
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thread_local volatile sig_atomic_t can_exit_now = false;
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static void sigint_handler(int signo) {}
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static void sigusr1_handler(int signo) {
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std::lock_guard<std::mutex> lock{print_mutex};
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std::printf("received SIGUSR1 on thread id: %" PRIx64 "\n", get_thread_id());
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can_exit_now = true;
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}
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static void thread_func() {
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// this ensures that all threads start before we stop
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pseudo_barrier_wait(barrier);
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// wait till the main thread indicates that we can go
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// (note: using a mutex here causes hang on FreeBSD when another thread
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// is suspended)
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while (!can_work.load())
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std::this_thread::sleep_for(std::chrono::milliseconds(50));
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// the mutex guarantees that two writes don't get interspersed
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{
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std::lock_guard<std::mutex> lock{print_mutex};
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std::printf("thread %" PRIx64 " running\n", get_thread_id());
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}
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// give other threads a fair chance to run
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for (int i = 0; i < 5; ++i) {
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std::this_thread::yield();
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std::this_thread::sleep_for(std::chrono::milliseconds(200));
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if (can_exit_now)
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return;
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}
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// if we didn't get signaled, terminate the program explicitly.
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_exit(0);
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}
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int main(int argc, char **argv) {
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int num = atoi(argv[1]);
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pseudo_barrier_init(barrier, num + 1);
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signal(SIGINT, sigint_handler);
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signal(SIGUSR1, sigusr1_handler);
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std::vector<std::thread> threads;
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for (int i = 0; i < num; ++i)
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threads.emplace_back(thread_func);
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// use the barrier to make sure all threads start before we stop
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pseudo_barrier_wait(barrier);
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std::raise(SIGINT);
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// allow the threads to work
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can_work.store(true);
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for (std::thread &thread : threads)
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thread.join();
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return 0;
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}
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