source: benchmark/schedint/pthreads.c @ 07997cd

#include <pthread.h>
#include <stdio.h>

#include "bench.h"

volatile int go = 0;

pthread_mutex_t m;
pthread_cond_t c;

void __attribute__((noinline)) call() {
        pthread_mutex_lock( &m );
        pthread_cond_signal( &c );
        pthread_mutex_unlock( &m );
}

void __attribute__((noinline)) wait() {
        pthread_mutex_lock(&m);
        go = 1;
        for ( size_t i = 0; i < times; i++ ) {
                pthread_cond_wait( &c, &m );
        }
        go = 0;
        pthread_mutex_unlock( &m );
}

void * thread_main( __attribute__((unused)) void * arg ) {
        while ( go == 0 ) { sched_yield(); } // waiter must start first
        // barging for lock acquire => may not execute N times
        BENCH(
                while ( go == 1 ) { call(); },
                result
        )
        printf( "%g\n", result );
        return NULL;
}

int main( int argc, char * argv[] ) {
        BENCH_START()
        pthread_t thread;
        if ( pthread_create( &thread, NULL, thread_main, NULL ) < 0 ) {
                perror( "failure" );
                return 1;
        }
        wait();
        if ( pthread_join( thread, NULL ) < 0 ) {
                perror( "failure" );
                return 1;
        }
}

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