104 lines
2.0 KiB
C
104 lines
2.0 KiB
C
#include <pthread.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <atomic.h>
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static pthread_cond_t cond1 = PTHREAD_COND_INITIALIZER;
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static pthread_mutex_t mut1 = PTHREAD_MUTEX_INITIALIZER;
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static pthread_cond_t cond2 = PTHREAD_COND_INITIALIZER;
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static pthread_mutex_t mut2 = PTHREAD_MUTEX_INITIALIZER;
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static bool last_round;
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static int ntogo;
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static bool alldone;
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static void *
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cons (void *arg)
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{
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pthread_mutex_lock (&mut1);
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do
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{
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if (atomic_decrement_and_test (&ntogo))
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{
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pthread_mutex_lock (&mut2);
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alldone = true;
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pthread_cond_signal (&cond2);
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pthread_mutex_unlock (&mut2);
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}
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pthread_cond_wait (&cond1, &mut1);
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}
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while (! last_round);
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pthread_mutex_unlock (&mut1);
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return NULL;
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}
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int
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main (int argc, char *argv[])
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{
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int opt;
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int err;
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int nthreads = 10;
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int nrounds = 100;
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bool keeplock = false;
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while ((opt = getopt (argc, argv, "n:r:k")) != -1)
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switch (opt)
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{
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case 'n':
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nthreads = atol (optarg);
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break;
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case 'r':
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nrounds = atol (optarg);
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break;
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case 'k':
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keeplock = true;
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break;
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}
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ntogo = nthreads;
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pthread_t th[nthreads];
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int i;
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for (i = 0; __builtin_expect (i < nthreads, 1); ++i)
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if (__glibc_unlikely ((err = pthread_create (&th[i], NULL, cons, (void *) (long) i)) != 0))
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printf ("pthread_create: %s\n", strerror (err));
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for (i = 0; __builtin_expect (i < nrounds, 1); ++i)
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{
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pthread_mutex_lock (&mut2);
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while (! alldone)
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pthread_cond_wait (&cond2, &mut2);
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pthread_mutex_unlock (&mut2);
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pthread_mutex_lock (&mut1);
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if (! keeplock)
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pthread_mutex_unlock (&mut1);
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ntogo = nthreads;
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alldone = false;
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if (i + 1 >= nrounds)
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last_round = true;
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pthread_cond_broadcast (&cond1);
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if (keeplock)
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pthread_mutex_unlock (&mut1);
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}
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for (i = 0; i < nthreads; ++i)
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if ((err = pthread_join (th[i], NULL)) != 0)
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printf ("pthread_create: %s\n", strerror (err));
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return 0;
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}
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