18c2ecf20Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0 28c2ecf20Sopenharmony_ci/* 38c2ecf20Sopenharmony_ci * Copyright (C) 2013 Davidlohr Bueso <davidlohr@hp.com> 48c2ecf20Sopenharmony_ci * 58c2ecf20Sopenharmony_ci * futex-wake: Block a bunch of threads on a futex and wake'em up, N at a time. 68c2ecf20Sopenharmony_ci * 78c2ecf20Sopenharmony_ci * This program is particularly useful to measure the latency of nthread wakeups 88c2ecf20Sopenharmony_ci * in non-error situations: all waiters are queued and all wake calls wakeup 98c2ecf20Sopenharmony_ci * one or more tasks, and thus the waitqueue is never empty. 108c2ecf20Sopenharmony_ci */ 118c2ecf20Sopenharmony_ci 128c2ecf20Sopenharmony_ci/* For the CLR_() macros */ 138c2ecf20Sopenharmony_ci#include <string.h> 148c2ecf20Sopenharmony_ci#include <pthread.h> 158c2ecf20Sopenharmony_ci 168c2ecf20Sopenharmony_ci#include <signal.h> 178c2ecf20Sopenharmony_ci#include "../util/stat.h" 188c2ecf20Sopenharmony_ci#include <subcmd/parse-options.h> 198c2ecf20Sopenharmony_ci#include <linux/compiler.h> 208c2ecf20Sopenharmony_ci#include <linux/kernel.h> 218c2ecf20Sopenharmony_ci#include <linux/time64.h> 228c2ecf20Sopenharmony_ci#include <errno.h> 238c2ecf20Sopenharmony_ci#include <internal/cpumap.h> 248c2ecf20Sopenharmony_ci#include <perf/cpumap.h> 258c2ecf20Sopenharmony_ci#include "bench.h" 268c2ecf20Sopenharmony_ci#include "futex.h" 278c2ecf20Sopenharmony_ci 288c2ecf20Sopenharmony_ci#include <err.h> 298c2ecf20Sopenharmony_ci#include <stdlib.h> 308c2ecf20Sopenharmony_ci#include <sys/time.h> 318c2ecf20Sopenharmony_ci 328c2ecf20Sopenharmony_ci/* all threads will block on the same futex */ 338c2ecf20Sopenharmony_cistatic u_int32_t futex1 = 0; 348c2ecf20Sopenharmony_ci 358c2ecf20Sopenharmony_ci/* 368c2ecf20Sopenharmony_ci * How many wakeups to do at a time. 378c2ecf20Sopenharmony_ci * Default to 1 in order to make the kernel work more. 388c2ecf20Sopenharmony_ci */ 398c2ecf20Sopenharmony_cistatic unsigned int nwakes = 1; 408c2ecf20Sopenharmony_ci 418c2ecf20Sopenharmony_cipthread_t *worker; 428c2ecf20Sopenharmony_cistatic bool done = false, silent = false, fshared = false; 438c2ecf20Sopenharmony_cistatic pthread_mutex_t thread_lock; 448c2ecf20Sopenharmony_cistatic pthread_cond_t thread_parent, thread_worker; 458c2ecf20Sopenharmony_cistatic struct stats waketime_stats, wakeup_stats; 468c2ecf20Sopenharmony_cistatic unsigned int threads_starting, nthreads = 0; 478c2ecf20Sopenharmony_cistatic int futex_flag = 0; 488c2ecf20Sopenharmony_ci 498c2ecf20Sopenharmony_cistatic const struct option options[] = { 508c2ecf20Sopenharmony_ci OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"), 518c2ecf20Sopenharmony_ci OPT_UINTEGER('w', "nwakes", &nwakes, "Specify amount of threads to wake at once"), 528c2ecf20Sopenharmony_ci OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"), 538c2ecf20Sopenharmony_ci OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"), 548c2ecf20Sopenharmony_ci OPT_END() 558c2ecf20Sopenharmony_ci}; 568c2ecf20Sopenharmony_ci 578c2ecf20Sopenharmony_cistatic const char * const bench_futex_wake_usage[] = { 588c2ecf20Sopenharmony_ci "perf bench futex wake <options>", 598c2ecf20Sopenharmony_ci NULL 608c2ecf20Sopenharmony_ci}; 618c2ecf20Sopenharmony_ci 628c2ecf20Sopenharmony_cistatic void *workerfn(void *arg __maybe_unused) 638c2ecf20Sopenharmony_ci{ 648c2ecf20Sopenharmony_ci pthread_mutex_lock(&thread_lock); 658c2ecf20Sopenharmony_ci threads_starting--; 668c2ecf20Sopenharmony_ci if (!threads_starting) 678c2ecf20Sopenharmony_ci pthread_cond_signal(&thread_parent); 688c2ecf20Sopenharmony_ci pthread_cond_wait(&thread_worker, &thread_lock); 698c2ecf20Sopenharmony_ci pthread_mutex_unlock(&thread_lock); 708c2ecf20Sopenharmony_ci 718c2ecf20Sopenharmony_ci while (1) { 728c2ecf20Sopenharmony_ci if (futex_wait(&futex1, 0, NULL, futex_flag) != EINTR) 738c2ecf20Sopenharmony_ci break; 748c2ecf20Sopenharmony_ci } 758c2ecf20Sopenharmony_ci 768c2ecf20Sopenharmony_ci pthread_exit(NULL); 778c2ecf20Sopenharmony_ci return NULL; 788c2ecf20Sopenharmony_ci} 798c2ecf20Sopenharmony_ci 808c2ecf20Sopenharmony_cistatic void print_summary(void) 818c2ecf20Sopenharmony_ci{ 828c2ecf20Sopenharmony_ci double waketime_avg = avg_stats(&waketime_stats); 838c2ecf20Sopenharmony_ci double waketime_stddev = stddev_stats(&waketime_stats); 848c2ecf20Sopenharmony_ci unsigned int wakeup_avg = avg_stats(&wakeup_stats); 858c2ecf20Sopenharmony_ci 868c2ecf20Sopenharmony_ci printf("Wokeup %d of %d threads in %.4f ms (+-%.2f%%)\n", 878c2ecf20Sopenharmony_ci wakeup_avg, 888c2ecf20Sopenharmony_ci nthreads, 898c2ecf20Sopenharmony_ci waketime_avg / USEC_PER_MSEC, 908c2ecf20Sopenharmony_ci rel_stddev_stats(waketime_stddev, waketime_avg)); 918c2ecf20Sopenharmony_ci} 928c2ecf20Sopenharmony_ci 938c2ecf20Sopenharmony_cistatic void block_threads(pthread_t *w, 948c2ecf20Sopenharmony_ci pthread_attr_t thread_attr, struct perf_cpu_map *cpu) 958c2ecf20Sopenharmony_ci{ 968c2ecf20Sopenharmony_ci cpu_set_t cpuset; 978c2ecf20Sopenharmony_ci unsigned int i; 988c2ecf20Sopenharmony_ci 998c2ecf20Sopenharmony_ci threads_starting = nthreads; 1008c2ecf20Sopenharmony_ci 1018c2ecf20Sopenharmony_ci /* create and block all threads */ 1028c2ecf20Sopenharmony_ci for (i = 0; i < nthreads; i++) { 1038c2ecf20Sopenharmony_ci CPU_ZERO(&cpuset); 1048c2ecf20Sopenharmony_ci CPU_SET(cpu->map[i % cpu->nr], &cpuset); 1058c2ecf20Sopenharmony_ci 1068c2ecf20Sopenharmony_ci if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset)) 1078c2ecf20Sopenharmony_ci err(EXIT_FAILURE, "pthread_attr_setaffinity_np"); 1088c2ecf20Sopenharmony_ci 1098c2ecf20Sopenharmony_ci if (pthread_create(&w[i], &thread_attr, workerfn, NULL)) 1108c2ecf20Sopenharmony_ci err(EXIT_FAILURE, "pthread_create"); 1118c2ecf20Sopenharmony_ci } 1128c2ecf20Sopenharmony_ci} 1138c2ecf20Sopenharmony_ci 1148c2ecf20Sopenharmony_cistatic void toggle_done(int sig __maybe_unused, 1158c2ecf20Sopenharmony_ci siginfo_t *info __maybe_unused, 1168c2ecf20Sopenharmony_ci void *uc __maybe_unused) 1178c2ecf20Sopenharmony_ci{ 1188c2ecf20Sopenharmony_ci done = true; 1198c2ecf20Sopenharmony_ci} 1208c2ecf20Sopenharmony_ci 1218c2ecf20Sopenharmony_ciint bench_futex_wake(int argc, const char **argv) 1228c2ecf20Sopenharmony_ci{ 1238c2ecf20Sopenharmony_ci int ret = 0; 1248c2ecf20Sopenharmony_ci unsigned int i, j; 1258c2ecf20Sopenharmony_ci struct sigaction act; 1268c2ecf20Sopenharmony_ci pthread_attr_t thread_attr; 1278c2ecf20Sopenharmony_ci struct perf_cpu_map *cpu; 1288c2ecf20Sopenharmony_ci 1298c2ecf20Sopenharmony_ci argc = parse_options(argc, argv, options, bench_futex_wake_usage, 0); 1308c2ecf20Sopenharmony_ci if (argc) { 1318c2ecf20Sopenharmony_ci usage_with_options(bench_futex_wake_usage, options); 1328c2ecf20Sopenharmony_ci exit(EXIT_FAILURE); 1338c2ecf20Sopenharmony_ci } 1348c2ecf20Sopenharmony_ci 1358c2ecf20Sopenharmony_ci cpu = perf_cpu_map__new(NULL); 1368c2ecf20Sopenharmony_ci if (!cpu) 1378c2ecf20Sopenharmony_ci err(EXIT_FAILURE, "calloc"); 1388c2ecf20Sopenharmony_ci 1398c2ecf20Sopenharmony_ci memset(&act, 0, sizeof(act)); 1408c2ecf20Sopenharmony_ci sigfillset(&act.sa_mask); 1418c2ecf20Sopenharmony_ci act.sa_sigaction = toggle_done; 1428c2ecf20Sopenharmony_ci sigaction(SIGINT, &act, NULL); 1438c2ecf20Sopenharmony_ci 1448c2ecf20Sopenharmony_ci if (!nthreads) 1458c2ecf20Sopenharmony_ci nthreads = cpu->nr; 1468c2ecf20Sopenharmony_ci 1478c2ecf20Sopenharmony_ci worker = calloc(nthreads, sizeof(*worker)); 1488c2ecf20Sopenharmony_ci if (!worker) 1498c2ecf20Sopenharmony_ci err(EXIT_FAILURE, "calloc"); 1508c2ecf20Sopenharmony_ci 1518c2ecf20Sopenharmony_ci if (!fshared) 1528c2ecf20Sopenharmony_ci futex_flag = FUTEX_PRIVATE_FLAG; 1538c2ecf20Sopenharmony_ci 1548c2ecf20Sopenharmony_ci printf("Run summary [PID %d]: blocking on %d threads (at [%s] futex %p), " 1558c2ecf20Sopenharmony_ci "waking up %d at a time.\n\n", 1568c2ecf20Sopenharmony_ci getpid(), nthreads, fshared ? "shared":"private", &futex1, nwakes); 1578c2ecf20Sopenharmony_ci 1588c2ecf20Sopenharmony_ci init_stats(&wakeup_stats); 1598c2ecf20Sopenharmony_ci init_stats(&waketime_stats); 1608c2ecf20Sopenharmony_ci pthread_attr_init(&thread_attr); 1618c2ecf20Sopenharmony_ci pthread_mutex_init(&thread_lock, NULL); 1628c2ecf20Sopenharmony_ci pthread_cond_init(&thread_parent, NULL); 1638c2ecf20Sopenharmony_ci pthread_cond_init(&thread_worker, NULL); 1648c2ecf20Sopenharmony_ci 1658c2ecf20Sopenharmony_ci for (j = 0; j < bench_repeat && !done; j++) { 1668c2ecf20Sopenharmony_ci unsigned int nwoken = 0; 1678c2ecf20Sopenharmony_ci struct timeval start, end, runtime; 1688c2ecf20Sopenharmony_ci 1698c2ecf20Sopenharmony_ci /* create, launch & block all threads */ 1708c2ecf20Sopenharmony_ci block_threads(worker, thread_attr, cpu); 1718c2ecf20Sopenharmony_ci 1728c2ecf20Sopenharmony_ci /* make sure all threads are already blocked */ 1738c2ecf20Sopenharmony_ci pthread_mutex_lock(&thread_lock); 1748c2ecf20Sopenharmony_ci while (threads_starting) 1758c2ecf20Sopenharmony_ci pthread_cond_wait(&thread_parent, &thread_lock); 1768c2ecf20Sopenharmony_ci pthread_cond_broadcast(&thread_worker); 1778c2ecf20Sopenharmony_ci pthread_mutex_unlock(&thread_lock); 1788c2ecf20Sopenharmony_ci 1798c2ecf20Sopenharmony_ci usleep(100000); 1808c2ecf20Sopenharmony_ci 1818c2ecf20Sopenharmony_ci /* Ok, all threads are patiently blocked, start waking folks up */ 1828c2ecf20Sopenharmony_ci gettimeofday(&start, NULL); 1838c2ecf20Sopenharmony_ci while (nwoken != nthreads) 1848c2ecf20Sopenharmony_ci nwoken += futex_wake(&futex1, nwakes, futex_flag); 1858c2ecf20Sopenharmony_ci gettimeofday(&end, NULL); 1868c2ecf20Sopenharmony_ci timersub(&end, &start, &runtime); 1878c2ecf20Sopenharmony_ci 1888c2ecf20Sopenharmony_ci update_stats(&wakeup_stats, nwoken); 1898c2ecf20Sopenharmony_ci update_stats(&waketime_stats, runtime.tv_usec); 1908c2ecf20Sopenharmony_ci 1918c2ecf20Sopenharmony_ci if (!silent) { 1928c2ecf20Sopenharmony_ci printf("[Run %d]: Wokeup %d of %d threads in %.4f ms\n", 1938c2ecf20Sopenharmony_ci j + 1, nwoken, nthreads, runtime.tv_usec / (double)USEC_PER_MSEC); 1948c2ecf20Sopenharmony_ci } 1958c2ecf20Sopenharmony_ci 1968c2ecf20Sopenharmony_ci for (i = 0; i < nthreads; i++) { 1978c2ecf20Sopenharmony_ci ret = pthread_join(worker[i], NULL); 1988c2ecf20Sopenharmony_ci if (ret) 1998c2ecf20Sopenharmony_ci err(EXIT_FAILURE, "pthread_join"); 2008c2ecf20Sopenharmony_ci } 2018c2ecf20Sopenharmony_ci 2028c2ecf20Sopenharmony_ci } 2038c2ecf20Sopenharmony_ci 2048c2ecf20Sopenharmony_ci /* cleanup & report results */ 2058c2ecf20Sopenharmony_ci pthread_cond_destroy(&thread_parent); 2068c2ecf20Sopenharmony_ci pthread_cond_destroy(&thread_worker); 2078c2ecf20Sopenharmony_ci pthread_mutex_destroy(&thread_lock); 2088c2ecf20Sopenharmony_ci pthread_attr_destroy(&thread_attr); 2098c2ecf20Sopenharmony_ci 2108c2ecf20Sopenharmony_ci print_summary(); 2118c2ecf20Sopenharmony_ci 2128c2ecf20Sopenharmony_ci free(worker); 2138c2ecf20Sopenharmony_ci perf_cpu_map__put(cpu); 2148c2ecf20Sopenharmony_ci return ret; 2158c2ecf20Sopenharmony_ci} 216