mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
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0d5c7f5c4c
And pass niters as a thread argument to all threading implementations... otherwise every loop has to do a memory load from the global!
52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
/* https://cirosantilli.com/linux-kernel-module-cheat#pthread-mutex */
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#define _XOPEN_SOURCE 700
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#include <assert.h>
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#include <pthread.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <unistd.h>
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unsigned long long global = 0;
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pthread_mutex_t main_thread_mutex = PTHREAD_MUTEX_INITIALIZER;
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void* main_thread(void *arg) {
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unsigned long long niters = *(unsigned long long *)arg;
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unsigned long long i;
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for (i = 0; i < niters; ++i) {
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pthread_mutex_lock(&main_thread_mutex);
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global++;
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pthread_mutex_unlock(&main_thread_mutex);
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}
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return NULL;
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}
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int main(int argc, char **argv) {
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pthread_t *threads;
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unsigned long long i, niters, nthreads;
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/* CLI arguments. */
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if (argc > 1) {
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nthreads = strtoull(argv[1], NULL, 0);
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} else {
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nthreads = 2;
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}
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if (argc > 2) {
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niters = strtoull(argv[2], NULL, 0);
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} else {
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niters = 10;
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}
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threads = malloc(sizeof(pthread_t) * nthreads);
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/* Action */
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for (i = 0; i < nthreads; ++i)
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pthread_create(&threads[i], NULL, main_thread, &niters);
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for (i = 0; i < nthreads; ++i)
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pthread_join(threads[i], NULL);
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assert(global == nthreads * niters);
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/* Cleanup. */
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free(threads);
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return EXIT_SUCCESS;
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}
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