60 lines
1.6 KiB
C
60 lines
1.6 KiB
C
#include <pthread.h>
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#include <stdlib.h>
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#include <stddef.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <time.h>
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int bench_nthread;
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int bench_niter;
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int grow_clock_var;
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pthread_barrier_t glow_clock_barrier;
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void bench(); // defined by user
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void start_thread_group(int nth, void(*f)(int tid));
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void grow_clock_worker(int tid);
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int main(int argc, char **argv) {
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bench_nthread = 2;
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if (argc > 1)
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bench_nthread = atoi(argv[1]);
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bench_niter = 100;
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if (argc > 2)
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bench_niter = atoi(argv[2]);
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// Grow thread's clock.
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int clock_size = 10;
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if (argc > 1)
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clock_size = 1000;
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pthread_barrier_init(&glow_clock_barrier, 0, clock_size);
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start_thread_group(clock_size, grow_clock_worker);
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pthread_barrier_destroy(&glow_clock_barrier);
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__atomic_load_n(&grow_clock_var, __ATOMIC_ACQUIRE);
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timespec tp0;
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clock_gettime(CLOCK_MONOTONIC, &tp0);
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bench();
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timespec tp1;
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clock_gettime(CLOCK_MONOTONIC, &tp1);
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unsigned long long t =
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(tp1.tv_sec * 1000000000ULL + tp1.tv_nsec) -
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(tp0.tv_sec * 1000000000ULL + tp0.tv_nsec);
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fprintf(stderr, "%llu ns/iter\n", t / bench_niter);
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fprintf(stderr, "DONE\n");
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}
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void start_thread_group(int nth, void(*f)(int tid)) {
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pthread_t *th = (pthread_t*)malloc(nth * sizeof(pthread_t));
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for (int i = 0; i < nth; i++)
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pthread_create(&th[i], 0, (void*(*)(void*))f, (void*)(long)i);
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for (int i = 0; i < nth; i++)
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pthread_join(th[i], 0);
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}
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void grow_clock_worker(int tid) {
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int res = pthread_barrier_wait(&glow_clock_barrier);
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if (res == PTHREAD_BARRIER_SERIAL_THREAD)
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__atomic_store_n(&grow_clock_var, 0, __ATOMIC_RELEASE);
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}
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