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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015 Davidlohr Bueso.
*/
/* For the CLR_() macros */
#include <string.h>
#include <pthread.h>
#include <signal.h>
#include "../util/stat.h"
#include <subcmd/parse-options.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
#include <errno.h>
#include <internal/cpumap.h>
#include <perf/cpumap.h>
#include "bench.h"
#include "futex.h"
#include <err.h>
#include <stdlib.h>
#include <sys/time.h>
struct worker {
int tid;
u_int32_t *futex;
pthread_t thread;
unsigned long ops;
};
static u_int32_t global_futex = 0;
static struct worker *worker;
static unsigned int nsecs = 10;
static bool silent = false, multi = false;
static bool done = false, fshared = false;
static unsigned int nthreads = 0;
static int futex_flag = 0;
static pthread_mutex_t thread_lock;
static unsigned int threads_starting;
static struct stats throughput_stats;
static pthread_cond_t thread_parent, thread_worker;
static const struct option options[] = {
OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"),
OPT_BOOLEAN( 'M', "multi", &multi, "Use multiple futexes"),
OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"),
OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"),
OPT_END()
};
static const char * const bench_futex_lock_pi_usage[] = {
"perf bench futex lock-pi <options>",
NULL
};
static void print_summary(void)
{
unsigned long avg = avg_stats(&throughput_stats);
double stddev = stddev_stats(&throughput_stats);
printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
!silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
(int)bench__runtime.tv_sec);
}
static void toggle_done(int sig __maybe_unused,
siginfo_t *info __maybe_unused,
void *uc __maybe_unused)
{
/* inform all threads that we're done for the day */
done = true;
gettimeofday(&bench__end, NULL);
timersub(&bench__end, &bench__start, &bench__runtime);
}
static void *workerfn(void *arg)
{
struct worker *w = (struct worker *) arg;
unsigned long ops = w->ops;
pthread_mutex_lock(&thread_lock);
threads_starting--;
if (!threads_starting)
pthread_cond_signal(&thread_parent);
pthread_cond_wait(&thread_worker, &thread_lock);
pthread_mutex_unlock(&thread_lock);
do {
int ret;
again:
ret = futex_lock_pi(w->futex, NULL, futex_flag);
if (ret) { /* handle lock acquisition */
if (!silent)
warn("thread %d: Could not lock pi-lock for %p (%d)",
w->tid, w->futex, ret);
if (done)
break;
goto again;
}
usleep(1);
ret = futex_unlock_pi(w->futex, futex_flag);
if (ret && !silent)
warn("thread %d: Could not unlock pi-lock for %p (%d)",
w->tid, w->futex, ret);
ops++; /* account for thread's share of work */
} while (!done);
w->ops = ops;
return NULL;
}
static void create_threads(struct worker *w, pthread_attr_t thread_attr,
struct perf_cpu_map *cpu)
{
cpu_set_t cpuset;
unsigned int i;
threads_starting = nthreads;
for (i = 0; i < nthreads; i++) {
worker[i].tid = i;
if (multi) {
worker[i].futex = calloc(1, sizeof(u_int32_t));
if (!worker[i].futex)
err(EXIT_FAILURE, "calloc");
} else
worker[i].futex = &global_futex;
CPU_ZERO(&cpuset);
CPU_SET(cpu->map[i % cpu->nr], &cpuset);
if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
err(EXIT_FAILURE, "pthread_create");
}
}
int bench_futex_lock_pi(int argc, const char **argv)
{
int ret = 0;
unsigned int i;
struct sigaction act;
pthread_attr_t thread_attr;
struct perf_cpu_map *cpu;
argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
if (argc)
goto err;
cpu = perf_cpu_map__new(NULL);
if (!cpu)
err(EXIT_FAILURE, "calloc");
sigfillset(&act.sa_mask);
act.sa_sigaction = toggle_done;
sigaction(SIGINT, &act, NULL);
if (!nthreads)
nthreads = cpu->nr;
worker = calloc(nthreads, sizeof(*worker));
if (!worker)
err(EXIT_FAILURE, "calloc");
if (!fshared)
futex_flag = FUTEX_PRIVATE_FLAG;
printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
getpid(), nthreads, nsecs);
init_stats(&throughput_stats);
pthread_mutex_init(&thread_lock, NULL);
pthread_cond_init(&thread_parent, NULL);
pthread_cond_init(&thread_worker, NULL);
threads_starting = nthreads;
pthread_attr_init(&thread_attr);
gettimeofday(&bench__start, NULL);
create_threads(worker, thread_attr, cpu);
pthread_attr_destroy(&thread_attr);
pthread_mutex_lock(&thread_lock);
while (threads_starting)
pthread_cond_wait(&thread_parent, &thread_lock);
pthread_cond_broadcast(&thread_worker);
pthread_mutex_unlock(&thread_lock);
sleep(nsecs);
toggle_done(0, NULL, NULL);
for (i = 0; i < nthreads; i++) {
ret = pthread_join(worker[i].thread, NULL);
if (ret)
err(EXIT_FAILURE, "pthread_join");
}
/* cleanup & report results */
pthread_cond_destroy(&thread_parent);
pthread_cond_destroy(&thread_worker);
pthread_mutex_destroy(&thread_lock);
for (i = 0; i < nthreads; i++) {
unsigned long t = worker[i].ops / bench__runtime.tv_sec;
update_stats(&throughput_stats, t);
if (!silent)
printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
worker[i].tid, worker[i].futex, t);
if (multi)
zfree(&worker[i].futex);
}
print_summary();
free(worker);
return ret;
err:
usage_with_options(bench_futex_lock_pi_usage, options);
exit(EXIT_FAILURE);
}
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