mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
314 lines
8.0 KiB
314 lines
8.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Copyright (C) 2013 Davidlohr Bueso <[email protected]> |
|
* |
|
* futex-requeue: Block a bunch of threads on futex1 and requeue them |
|
* on futex2, N at a time. |
|
* |
|
* This program is particularly useful to measure the latency of nthread |
|
* requeues without waking up any tasks (in the non-pi case) -- thus |
|
* mimicking a regular futex_wait. |
|
*/ |
|
|
|
/* For the CLR_() macros */ |
|
#include <string.h> |
|
#include <pthread.h> |
|
|
|
#include <signal.h> |
|
#include "../util/mutex.h" |
|
#include "../util/stat.h" |
|
#include <subcmd/parse-options.h> |
|
#include <linux/compiler.h> |
|
#include <linux/kernel.h> |
|
#include <linux/time64.h> |
|
#include <errno.h> |
|
#include <perf/cpumap.h> |
|
#include "bench.h" |
|
#include "futex.h" |
|
|
|
#include <err.h> |
|
#include <stdlib.h> |
|
#include <sys/time.h> |
|
#include <sys/mman.h> |
|
|
|
static u_int32_t futex1 = 0, futex2 = 0; |
|
|
|
static pthread_t *worker; |
|
static bool done = false; |
|
static struct mutex thread_lock; |
|
static struct cond thread_parent, thread_worker; |
|
static struct stats requeuetime_stats, requeued_stats; |
|
static unsigned int threads_starting; |
|
static int futex_flag = 0; |
|
|
|
static struct bench_futex_parameters params = { |
|
/* |
|
* How many tasks to requeue at a time. |
|
* Default to 1 in order to make the kernel work more. |
|
*/ |
|
.nrequeue = 1, |
|
}; |
|
|
|
static const struct option options[] = { |
|
OPT_UINTEGER('t', "threads", ¶ms.nthreads, "Specify amount of threads"), |
|
OPT_UINTEGER('q', "nrequeue", ¶ms.nrequeue, "Specify amount of threads to requeue at once"), |
|
OPT_BOOLEAN( 's', "silent", ¶ms.silent, "Silent mode: do not display data/details"), |
|
OPT_BOOLEAN( 'S', "shared", ¶ms.fshared, "Use shared futexes instead of private ones"), |
|
OPT_BOOLEAN( 'm', "mlockall", ¶ms.mlockall, "Lock all current and future memory"), |
|
OPT_BOOLEAN( 'B', "broadcast", ¶ms.broadcast, "Requeue all threads at once"), |
|
OPT_BOOLEAN( 'p', "pi", ¶ms.pi, "Use PI-aware variants of FUTEX_CMP_REQUEUE"), |
|
|
|
OPT_END() |
|
}; |
|
|
|
static const char * const bench_futex_requeue_usage[] = { |
|
"perf bench futex requeue <options>", |
|
NULL |
|
}; |
|
|
|
static void print_summary(void) |
|
{ |
|
double requeuetime_avg = avg_stats(&requeuetime_stats); |
|
double requeuetime_stddev = stddev_stats(&requeuetime_stats); |
|
unsigned int requeued_avg = avg_stats(&requeued_stats); |
|
|
|
printf("Requeued %d of %d threads in %.4f ms (+-%.2f%%)\n", |
|
requeued_avg, |
|
params.nthreads, |
|
requeuetime_avg / USEC_PER_MSEC, |
|
rel_stddev_stats(requeuetime_stddev, requeuetime_avg)); |
|
} |
|
|
|
static void *workerfn(void *arg __maybe_unused) |
|
{ |
|
int ret; |
|
|
|
mutex_lock(&thread_lock); |
|
threads_starting--; |
|
if (!threads_starting) |
|
cond_signal(&thread_parent); |
|
cond_wait(&thread_worker, &thread_lock); |
|
mutex_unlock(&thread_lock); |
|
|
|
while (1) { |
|
if (!params.pi) { |
|
ret = futex_wait(&futex1, 0, NULL, futex_flag); |
|
if (!ret) |
|
break; |
|
|
|
if (ret && errno != EAGAIN) { |
|
if (!params.silent) |
|
warnx("futex_wait"); |
|
break; |
|
} |
|
} else { |
|
ret = futex_wait_requeue_pi(&futex1, 0, &futex2, |
|
NULL, futex_flag); |
|
if (!ret) { |
|
/* got the lock at futex2 */ |
|
futex_unlock_pi(&futex2, futex_flag); |
|
break; |
|
} |
|
|
|
if (ret && errno != EAGAIN) { |
|
if (!params.silent) |
|
warnx("futex_wait_requeue_pi"); |
|
break; |
|
} |
|
} |
|
} |
|
|
|
return NULL; |
|
} |
|
|
|
static void block_threads(pthread_t *w, |
|
pthread_attr_t thread_attr, struct perf_cpu_map *cpu) |
|
{ |
|
cpu_set_t *cpuset; |
|
unsigned int i; |
|
int nrcpus = perf_cpu_map__nr(cpu); |
|
size_t size; |
|
|
|
threads_starting = params.nthreads; |
|
|
|
cpuset = CPU_ALLOC(nrcpus); |
|
BUG_ON(!cpuset); |
|
size = CPU_ALLOC_SIZE(nrcpus); |
|
|
|
/* create and block all threads */ |
|
for (i = 0; i < params.nthreads; i++) { |
|
CPU_ZERO_S(size, cpuset); |
|
CPU_SET_S(perf_cpu_map__cpu(cpu, i % perf_cpu_map__nr(cpu)).cpu, size, cpuset); |
|
|
|
if (pthread_attr_setaffinity_np(&thread_attr, size, cpuset)) { |
|
CPU_FREE(cpuset); |
|
err(EXIT_FAILURE, "pthread_attr_setaffinity_np"); |
|
} |
|
|
|
if (pthread_create(&w[i], &thread_attr, workerfn, NULL)) { |
|
CPU_FREE(cpuset); |
|
err(EXIT_FAILURE, "pthread_create"); |
|
} |
|
} |
|
CPU_FREE(cpuset); |
|
} |
|
|
|
static void toggle_done(int sig __maybe_unused, |
|
siginfo_t *info __maybe_unused, |
|
void *uc __maybe_unused) |
|
{ |
|
done = true; |
|
} |
|
|
|
int bench_futex_requeue(int argc, const char **argv) |
|
{ |
|
int ret = 0; |
|
unsigned int i, j; |
|
struct sigaction act; |
|
pthread_attr_t thread_attr; |
|
struct perf_cpu_map *cpu; |
|
|
|
argc = parse_options(argc, argv, options, bench_futex_requeue_usage, 0); |
|
if (argc) |
|
goto err; |
|
|
|
cpu = perf_cpu_map__new(NULL); |
|
if (!cpu) |
|
err(EXIT_FAILURE, "cpu_map__new"); |
|
|
|
memset(&act, 0, sizeof(act)); |
|
sigfillset(&act.sa_mask); |
|
act.sa_sigaction = toggle_done; |
|
sigaction(SIGINT, &act, NULL); |
|
|
|
if (params.mlockall) { |
|
if (mlockall(MCL_CURRENT | MCL_FUTURE)) |
|
err(EXIT_FAILURE, "mlockall"); |
|
} |
|
|
|
if (!params.nthreads) |
|
params.nthreads = perf_cpu_map__nr(cpu); |
|
|
|
worker = calloc(params.nthreads, sizeof(*worker)); |
|
if (!worker) |
|
err(EXIT_FAILURE, "calloc"); |
|
|
|
if (!params.fshared) |
|
futex_flag = FUTEX_PRIVATE_FLAG; |
|
|
|
if (params.nrequeue > params.nthreads) |
|
params.nrequeue = params.nthreads; |
|
|
|
if (params.broadcast) |
|
params.nrequeue = params.nthreads; |
|
|
|
printf("Run summary [PID %d]: Requeuing %d threads (from [%s] %p to %s%p), " |
|
"%d at a time.\n\n", getpid(), params.nthreads, |
|
params.fshared ? "shared":"private", &futex1, |
|
params.pi ? "PI ": "", &futex2, params.nrequeue); |
|
|
|
init_stats(&requeued_stats); |
|
init_stats(&requeuetime_stats); |
|
pthread_attr_init(&thread_attr); |
|
mutex_init(&thread_lock); |
|
cond_init(&thread_parent); |
|
cond_init(&thread_worker); |
|
|
|
for (j = 0; j < bench_repeat && !done; j++) { |
|
unsigned int nrequeued = 0, wakeups = 0; |
|
struct timeval start, end, runtime; |
|
|
|
/* create, launch & block all threads */ |
|
block_threads(worker, thread_attr, cpu); |
|
|
|
/* make sure all threads are already blocked */ |
|
mutex_lock(&thread_lock); |
|
while (threads_starting) |
|
cond_wait(&thread_parent, &thread_lock); |
|
cond_broadcast(&thread_worker); |
|
mutex_unlock(&thread_lock); |
|
|
|
usleep(100000); |
|
|
|
/* Ok, all threads are patiently blocked, start requeueing */ |
|
gettimeofday(&start, NULL); |
|
while (nrequeued < params.nthreads) { |
|
int r; |
|
|
|
/* |
|
* For the regular non-pi case, do not wakeup any tasks |
|
* blocked on futex1, allowing us to really measure |
|
* futex_wait functionality. For the PI case the first |
|
* waiter is always awoken. |
|
*/ |
|
if (!params.pi) { |
|
r = futex_cmp_requeue(&futex1, 0, &futex2, 0, |
|
params.nrequeue, |
|
futex_flag); |
|
} else { |
|
r = futex_cmp_requeue_pi(&futex1, 0, &futex2, |
|
params.nrequeue, |
|
futex_flag); |
|
wakeups++; /* assume no error */ |
|
} |
|
|
|
if (r < 0) |
|
err(EXIT_FAILURE, "couldn't requeue from %p to %p", |
|
&futex1, &futex2); |
|
|
|
nrequeued += r; |
|
} |
|
|
|
gettimeofday(&end, NULL); |
|
timersub(&end, &start, &runtime); |
|
|
|
update_stats(&requeued_stats, nrequeued); |
|
update_stats(&requeuetime_stats, runtime.tv_usec); |
|
|
|
if (!params.silent) { |
|
if (!params.pi) |
|
printf("[Run %d]: Requeued %d of %d threads in " |
|
"%.4f ms\n", j + 1, nrequeued, |
|
params.nthreads, |
|
runtime.tv_usec / (double)USEC_PER_MSEC); |
|
else { |
|
nrequeued -= wakeups; |
|
printf("[Run %d]: Awoke and Requeued (%d+%d) of " |
|
"%d threads in %.4f ms\n", |
|
j + 1, wakeups, nrequeued, |
|
params.nthreads, |
|
runtime.tv_usec / (double)USEC_PER_MSEC); |
|
} |
|
|
|
} |
|
|
|
if (!params.pi) { |
|
/* everybody should be blocked on futex2, wake'em up */ |
|
nrequeued = futex_wake(&futex2, nrequeued, futex_flag); |
|
if (params.nthreads != nrequeued) |
|
warnx("couldn't wakeup all tasks (%d/%d)", |
|
nrequeued, params.nthreads); |
|
} |
|
|
|
for (i = 0; i < params.nthreads; i++) { |
|
ret = pthread_join(worker[i], NULL); |
|
if (ret) |
|
err(EXIT_FAILURE, "pthread_join"); |
|
} |
|
} |
|
|
|
/* cleanup & report results */ |
|
cond_destroy(&thread_parent); |
|
cond_destroy(&thread_worker); |
|
mutex_destroy(&thread_lock); |
|
pthread_attr_destroy(&thread_attr); |
|
|
|
print_summary(); |
|
|
|
free(worker); |
|
perf_cpu_map__put(cpu); |
|
return ret; |
|
err: |
|
usage_with_options(bench_futex_requeue_usage, options); |
|
exit(EXIT_FAILURE); |
|
}
|
|
|