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230 lines
6.1 KiB
230 lines
6.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2013 Davidlohr Bueso <[email protected]> |
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* |
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* futex-hash: Stress the hell out of the Linux kernel futex uaddr hashing. |
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* |
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* This program is particularly useful for measuring the kernel's futex hash |
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* table/function implementation. In order for it to make sense, use with as |
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* many threads and futexes as possible. |
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*/ |
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/* For the CLR_() macros */ |
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#include <string.h> |
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#include <pthread.h> |
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#include <errno.h> |
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#include <signal.h> |
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#include <stdlib.h> |
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#include <linux/compiler.h> |
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#include <linux/kernel.h> |
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#include <linux/zalloc.h> |
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#include <sys/time.h> |
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#include <perf/cpumap.h> |
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#include "../util/stat.h" |
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#include <subcmd/parse-options.h> |
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#include "bench.h" |
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#include "futex.h" |
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#include <err.h> |
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static unsigned int nthreads = 0; |
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static unsigned int nsecs = 10; |
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/* amount of futexes per thread */ |
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static unsigned int nfutexes = 1024; |
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static bool fshared = false, done = false, silent = false; |
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static int futex_flag = 0; |
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struct timeval bench__start, bench__end, bench__runtime; |
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static pthread_mutex_t thread_lock; |
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static unsigned int threads_starting; |
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static struct stats throughput_stats; |
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static pthread_cond_t thread_parent, thread_worker; |
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struct worker { |
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int tid; |
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u_int32_t *futex; |
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pthread_t thread; |
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unsigned long ops; |
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}; |
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static const struct option options[] = { |
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OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"), |
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OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"), |
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OPT_UINTEGER('f', "futexes", &nfutexes, "Specify amount of futexes per threads"), |
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OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"), |
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OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"), |
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OPT_END() |
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}; |
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static const char * const bench_futex_hash_usage[] = { |
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"perf bench futex hash <options>", |
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NULL |
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}; |
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static void *workerfn(void *arg) |
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{ |
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int ret; |
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struct worker *w = (struct worker *) arg; |
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unsigned int i; |
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unsigned long ops = w->ops; /* avoid cacheline bouncing */ |
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pthread_mutex_lock(&thread_lock); |
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threads_starting--; |
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if (!threads_starting) |
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pthread_cond_signal(&thread_parent); |
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pthread_cond_wait(&thread_worker, &thread_lock); |
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pthread_mutex_unlock(&thread_lock); |
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do { |
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for (i = 0; i < nfutexes; i++, ops++) { |
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/* |
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* We want the futex calls to fail in order to stress |
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* the hashing of uaddr and not measure other steps, |
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* such as internal waitqueue handling, thus enlarging |
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* the critical region protected by hb->lock. |
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*/ |
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ret = futex_wait(&w->futex[i], 1234, NULL, futex_flag); |
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if (!silent && |
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(!ret || errno != EAGAIN || errno != EWOULDBLOCK)) |
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warn("Non-expected futex return call"); |
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} |
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} while (!done); |
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w->ops = ops; |
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return NULL; |
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} |
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static void toggle_done(int sig __maybe_unused, |
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siginfo_t *info __maybe_unused, |
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void *uc __maybe_unused) |
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{ |
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/* inform all threads that we're done for the day */ |
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done = true; |
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gettimeofday(&bench__end, NULL); |
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timersub(&bench__end, &bench__start, &bench__runtime); |
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} |
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static void print_summary(void) |
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{ |
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unsigned long avg = avg_stats(&throughput_stats); |
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double stddev = stddev_stats(&throughput_stats); |
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printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n", |
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!silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg), |
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(int)bench__runtime.tv_sec); |
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} |
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int bench_futex_hash(int argc, const char **argv) |
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{ |
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int ret = 0; |
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cpu_set_t cpuset; |
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struct sigaction act; |
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unsigned int i; |
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pthread_attr_t thread_attr; |
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struct worker *worker = NULL; |
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struct perf_cpu_map *cpu; |
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argc = parse_options(argc, argv, options, bench_futex_hash_usage, 0); |
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if (argc) { |
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usage_with_options(bench_futex_hash_usage, options); |
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exit(EXIT_FAILURE); |
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} |
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cpu = perf_cpu_map__new(NULL); |
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if (!cpu) |
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goto errmem; |
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memset(&act, 0, sizeof(act)); |
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sigfillset(&act.sa_mask); |
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act.sa_sigaction = toggle_done; |
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sigaction(SIGINT, &act, NULL); |
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if (!nthreads) /* default to the number of CPUs */ |
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nthreads = cpu->nr; |
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worker = calloc(nthreads, sizeof(*worker)); |
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if (!worker) |
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goto errmem; |
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if (!fshared) |
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futex_flag = FUTEX_PRIVATE_FLAG; |
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printf("Run summary [PID %d]: %d threads, each operating on %d [%s] futexes for %d secs.\n\n", |
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getpid(), nthreads, nfutexes, fshared ? "shared":"private", nsecs); |
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init_stats(&throughput_stats); |
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pthread_mutex_init(&thread_lock, NULL); |
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pthread_cond_init(&thread_parent, NULL); |
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pthread_cond_init(&thread_worker, NULL); |
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threads_starting = nthreads; |
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pthread_attr_init(&thread_attr); |
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gettimeofday(&bench__start, NULL); |
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for (i = 0; i < nthreads; i++) { |
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worker[i].tid = i; |
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worker[i].futex = calloc(nfutexes, sizeof(*worker[i].futex)); |
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if (!worker[i].futex) |
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goto errmem; |
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CPU_ZERO(&cpuset); |
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CPU_SET(cpu->map[i % cpu->nr], &cpuset); |
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ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset); |
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if (ret) |
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err(EXIT_FAILURE, "pthread_attr_setaffinity_np"); |
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ret = pthread_create(&worker[i].thread, &thread_attr, workerfn, |
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(void *)(struct worker *) &worker[i]); |
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if (ret) |
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err(EXIT_FAILURE, "pthread_create"); |
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} |
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pthread_attr_destroy(&thread_attr); |
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pthread_mutex_lock(&thread_lock); |
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while (threads_starting) |
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pthread_cond_wait(&thread_parent, &thread_lock); |
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pthread_cond_broadcast(&thread_worker); |
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pthread_mutex_unlock(&thread_lock); |
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sleep(nsecs); |
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toggle_done(0, NULL, NULL); |
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for (i = 0; i < nthreads; i++) { |
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ret = pthread_join(worker[i].thread, NULL); |
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if (ret) |
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err(EXIT_FAILURE, "pthread_join"); |
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} |
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/* cleanup & report results */ |
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pthread_cond_destroy(&thread_parent); |
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pthread_cond_destroy(&thread_worker); |
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pthread_mutex_destroy(&thread_lock); |
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for (i = 0; i < nthreads; i++) { |
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unsigned long t = bench__runtime.tv_sec > 0 ? |
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worker[i].ops / bench__runtime.tv_sec : 0; |
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update_stats(&throughput_stats, t); |
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if (!silent) { |
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if (nfutexes == 1) |
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printf("[thread %2d] futex: %p [ %ld ops/sec ]\n", |
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worker[i].tid, &worker[i].futex[0], t); |
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else |
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printf("[thread %2d] futexes: %p ... %p [ %ld ops/sec ]\n", |
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worker[i].tid, &worker[i].futex[0], |
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&worker[i].futex[nfutexes-1], t); |
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} |
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zfree(&worker[i].futex); |
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} |
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print_summary(); |
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free(worker); |
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free(cpu); |
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return ret; |
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errmem: |
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err(EXIT_FAILURE, "calloc"); |
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}
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