blob: d11c89a97b24782ea56e9f920a9cd873417f4b5f [file] [log] [blame]
/*
* Copyright (C) 2013 Davidlohr Bueso <davidlohr@hp.com>
*
* futex-hash: Stress the hell out of the Linux kernel futex uaddr hashing.
*
* This program is particularly useful for measuring the kernel's futex hash
* table/function implementation. In order for it to make sense, use with as
* many threads and futexes as possible.
*/
/* For the CLR_() macros */
#include <pthread.h>
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <sys/time.h>
#include "../util/stat.h"
#include <subcmd/parse-options.h>
#include "bench.h"
#include "futex.h"
#include <err.h>
#include <sys/time.h>
#ifdef CONFIG_NUMA
#include <numa.h>
#endif
#define FUTEX_ATTACH 13
#define FUTEX_ATTACHED 512
static unsigned int nthreads = 0;
static unsigned int nsecs = 10;
/* amount of futexes per thread */
static unsigned int nfutexes = 1024;
static bool fshared = false, done = false, silent = false;
static int futex_flag = 0;
static int numa_node = -1;
struct timeval start, end, runtime;
static pthread_mutex_t thread_lock;
static unsigned int threads_starting;
static struct stats throughput_stats;
static pthread_cond_t thread_parent, thread_worker;
struct worker {
int tid;
u_int32_t *futex;
pthread_t thread;
unsigned long ops;
} __attribute__((aligned(128)));
static const struct option options[] = {
OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"),
OPT_UINTEGER('f', "futexes", &nfutexes, "Specify amount of futexes per threads"),
OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"),
OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"),
#ifdef CONFIG_NUMA
OPT_INTEGER( 'n', "numa", &numa_node, "Specify the NUMA node"),
#endif
OPT_END()
};
#ifndef CONFIG_NUMA
static int numa_run_on_node(int node __maybe_unused) { return 0; }
static int numa_node_of_cpu(int node __maybe_unused) { return 0; }
static void *numa_alloc_local(size_t size) { return malloc(size); }
static void numa_free(void *p, size_t size __maybe_unused) { return free(p); }
#endif
static bool cpu_is_local(int cpu)
{
if (numa_node < 0)
return true;
if (numa_node_of_cpu(cpu) == numa_node)
return true;
return false;
}
static const char * const bench_futex_hash_usage[] = {
"perf bench futex hash <options>",
NULL
};
static void *workerfn(void *arg)
{
int ret;
unsigned int i;
struct worker *w = (struct worker *) arg;
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 {
for (i = 0; i < nfutexes; i++, w->ops++) {
/*
* We want the futex calls to fail in order to stress
* the hashing of uaddr and not measure other steps,
* such as internal waitqueue handling, thus enlarging
* the critical region protected by hb->lock.
*/
ret = futex_wait(&w->futex[i], 1234, NULL, futex_flag);
if (!silent &&
(!ret || errno != EAGAIN || errno != EWOULDBLOCK))
warn("Non-expected futex return call");
}
} while (!done);
return NULL;
}
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(&end, NULL);
timersub(&end, &start, &runtime);
}
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) runtime.tv_sec);
}
static int futex_attach(u_int32_t *uaddr, unsigned int opflags)
{
return futex(uaddr, FUTEX_ATTACH, 0, 0, NULL, 0, opflags);
}
int bench_futex_hash(int argc, const char **argv,
const char *prefix __maybe_unused)
{
int ret = 0;
cpu_set_t cpu;
struct sigaction act;
unsigned int i, ncpus;
pthread_attr_t thread_attr;
struct worker *worker = NULL;
char *node_str = NULL;
unsigned int cpunum;
argc = parse_options(argc, argv, options, bench_futex_hash_usage, 0);
if (argc) {
usage_with_options(bench_futex_hash_usage, options);
exit(EXIT_FAILURE);
}
ncpus = sysconf(_SC_NPROCESSORS_ONLN);
sigfillset(&act.sa_mask);
act.sa_sigaction = toggle_done;
sigaction(SIGINT, &act, NULL);
if (!nthreads) {
/* default to the number of CPUs per NUMA node */
if (numa_node < 0) {
nthreads = ncpus;
} else {
for (i = 0; i < ncpus; i++) {
if (cpu_is_local(i))
nthreads++;
}
if (!nthreads)
err(EXIT_FAILURE, "No online CPUs for this node");
}
} else {
int cpu_available = 0;
for (i = 0; i < ncpus && !cpu_available; i++) {
if (cpu_is_local(i))
cpu_available = 1;
}
if (!cpu_available)
err(EXIT_FAILURE, "No online CPUs for this node");
}
if (numa_node >= 0) {
ret = numa_run_on_node(numa_node);
if (ret < 0)
err(EXIT_FAILURE, "numa_run_on_node");
ret = asprintf(&node_str, " on node %d", numa_node);
if (ret < 0)
err(EXIT_FAILURE, "numa_node, asprintf");
}
worker = numa_alloc_local(nthreads * sizeof(*worker));
if (!worker)
goto errmem;
if (!fshared)
futex_flag = FUTEX_PRIVATE_FLAG | FUTEX_ATTACHED;
printf("Run summary [PID %d]: %d threads%s, each operating on %d [%s] futexes for %d secs.\n\n",
getpid(), nthreads,
node_str ? : "",
nfutexes, fshared ? "shared":"private",
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(&start, NULL);
for (cpunum = 0, i = 0; i < nthreads; i++, cpunum++) {
unsigned int f_init;
do {
if (cpu_is_local(cpunum))
break;
cpunum++;
if (cpunum > ncpus)
cpunum = 0;
} while (1);
worker[i].tid = i;
worker[i].futex = numa_alloc_local(nfutexes *
sizeof(*worker[i].futex));
if (!worker[i].futex)
goto errmem;
if (futex_flag & FUTEX_ATTACHED) {
for (f_init = 0; f_init < nfutexes; f_init++) {
ret = futex_attach(&worker[i].futex[f_init], futex_flag);
if (ret)
err(EXIT_FAILURE, "Can't attached futex cpu%d futex%d",
i, f_init);
}
}
CPU_ZERO(&cpu);
CPU_SET(cpunum % ncpus, &cpu);
ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu);
if (ret)
err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
ret = pthread_create(&worker[i].thread, &thread_attr, workerfn,
(void *)(struct worker *) &worker[i]);
if (ret)
err(EXIT_FAILURE, "pthread_create");
}
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/runtime.tv_sec;
update_stats(&throughput_stats, t);
if (!silent) {
if (nfutexes == 1)
printf("[thread %2d] futex: %p [ %ld ops/sec ]\n",
worker[i].tid, &worker[i].futex[0], t);
else
printf("[thread %2d] futexes: %p ... %p [ %ld ops/sec ]\n",
worker[i].tid, &worker[i].futex[0],
&worker[i].futex[nfutexes-1], t);
}
numa_free(worker[i].futex, nfutexes * sizeof(*worker[i].futex));
}
print_summary();
numa_free(worker, nthreads * sizeof(*worker));
return ret;
errmem:
err(EXIT_FAILURE, "calloc");
}