perf bench: Add futex-hash microbenchmark
Introduce futexes to perf-bench and add a program that stresses and measures the kernel's implementation of the hash table. This is a multi-threaded program that simply measures the amount of failed futex wait calls - we only want to deal with the hashing overhead, so a negative return of futex_wait_setup() is enough to do the trick. An example run: $ perf bench futex hash -t 32 Run summary [PID 10989]: 32 threads, each operating on 1024 [private] futexes for 10 secs. [thread 0] futexes: 0x19d9b10 ... 0x19dab0c [ 418713 ops/sec ] [thread 1] futexes: 0x19daca0 ... 0x19dbc9c [ 469913 ops/sec ] [thread 2] futexes: 0x19dbe30 ... 0x19dce2c [ 479744 ops/sec ] ... [thread 31] futexes: 0x19fbb80 ... 0x19fcb7c [ 464179 ops/sec ] Averaged 454310 operations/sec (+- 0.84%), total secs = 10 Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Acked-by: Darren Hart <dvhart@linux.intel.com> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Darren Hart <dvhart@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Low <jason.low2@hp.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Scott J Norton <scott.norton@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <Waiman.Long@hp.com> Link: http://lkml.kernel.org/r/1387081917-9102-2-git-send-email-davidlohr@hp.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Davidlohr Bueso
Arnaldo Carvalho de Melo
parent
81827ed8d8
commit
a043971141
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@ -426,6 +426,7 @@ BUILTIN_OBJS += $(OUTPUT)bench/mem-memset-x86-64-asm.o
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endif
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BUILTIN_OBJS += $(OUTPUT)bench/mem-memcpy.o
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BUILTIN_OBJS += $(OUTPUT)bench/mem-memset.o
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BUILTIN_OBJS += $(OUTPUT)bench/futex-hash.o
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BUILTIN_OBJS += $(OUTPUT)builtin-diff.o
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BUILTIN_OBJS += $(OUTPUT)builtin-evlist.o
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@ -31,6 +31,7 @@ extern int bench_sched_pipe(int argc, const char **argv, const char *prefix);
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extern int bench_mem_memcpy(int argc, const char **argv,
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const char *prefix __maybe_unused);
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extern int bench_mem_memset(int argc, const char **argv, const char *prefix);
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extern int bench_futex_hash(int argc, const char **argv, const char *prefix);
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#define BENCH_FORMAT_DEFAULT_STR "default"
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#define BENCH_FORMAT_DEFAULT 0
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@ -0,0 +1,212 @@
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/*
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* Copyright (C) 2013 Davidlohr Bueso <davidlohr@hp.com>
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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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#include "../perf.h"
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#include "../util/util.h"
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#include "../util/stat.h"
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#include "../util/parse-options.h"
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#include "../util/header.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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#include <stdlib.h>
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#include <sys/time.h>
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#include <pthread.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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struct timeval start, end, 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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unsigned int i;
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struct worker *w = (struct worker *) arg;
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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++, w->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,
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fshared ? 0 : FUTEX_PRIVATE_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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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(&end, NULL);
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timersub(&end, &start, &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) runtime.tv_sec);
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}
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int bench_futex_hash(int argc, const char **argv,
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const char *prefix __maybe_unused)
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{
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int ret = 0;
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cpu_set_t cpu;
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struct sigaction act;
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unsigned int i, ncpus;
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pthread_attr_t thread_attr;
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struct worker *worker = NULL;
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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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ncpus = sysconf(_SC_NPROCESSORS_ONLN);
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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 = ncpus;
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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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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(&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(&cpu);
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CPU_SET(i % ncpus, &cpu);
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ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu);
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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 = worker[i].ops/runtime.tv_sec;
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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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free(worker[i].futex);
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}
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print_summary();
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free(worker);
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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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@ -0,0 +1,48 @@
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/*
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* Glibc independent futex library for testing kernel functionality.
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* Shamelessly stolen from Darren Hart <dvhltc@us.ibm.com>
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* http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/
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*/
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#ifndef _FUTEX_H
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#define _FUTEX_H
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <sys/types.h>
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#include <linux/futex.h>
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/**
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* futex() - SYS_futex syscall wrapper
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* @uaddr: address of first futex
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* @op: futex op code
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* @val: typically expected value of uaddr, but varies by op
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* @timeout: typically an absolute struct timespec (except where noted
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* otherwise). Overloaded by some ops
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* @uaddr2: address of second futex for some ops\
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* @val3: varies by op
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* @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
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*
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* futex() is used by all the following futex op wrappers. It can also be
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* used for misuse and abuse testing. Generally, the specific op wrappers
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* should be used instead. It is a macro instead of an static inline function as
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* some of the types over overloaded (timeout is used for nr_requeue for
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* example).
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*
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* These argument descriptions are the defaults for all
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* like-named arguments in the following wrappers except where noted below.
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*/
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#define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \
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syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3)
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/**
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* futex_wait() - block on uaddr with optional timeout
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* @timeout: relative timeout
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*/
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static inline int
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futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
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{
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return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
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}
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#endif /* _FUTEX_H */
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@ -12,6 +12,7 @@
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* sched ... scheduler and IPC performance
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* mem ... memory access performance
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* numa ... NUMA scheduling and MM performance
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* futex ... Futex performance
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*/
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#include "perf.h"
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#include "util/util.h"
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@ -54,6 +55,12 @@ static struct bench mem_benchmarks[] = {
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{ NULL, NULL, NULL }
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};
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static struct bench futex_benchmarks[] = {
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{ "hash", "Benchmark for futex hash table", bench_futex_hash },
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{ "all", "Test all futex benchmarks", NULL },
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{ NULL, NULL, NULL }
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};
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struct collection {
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const char *name;
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const char *summary;
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@ -61,11 +68,12 @@ struct collection {
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};
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static struct collection collections[] = {
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{ "sched", "Scheduler and IPC benchmarks", sched_benchmarks },
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{ "sched", "Scheduler and IPC benchmarks", sched_benchmarks },
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{ "mem", "Memory access benchmarks", mem_benchmarks },
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#ifdef HAVE_LIBNUMA_SUPPORT
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{ "numa", "NUMA scheduling and MM benchmarks", numa_benchmarks },
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#endif
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{"futex", "Futex stressing benchmarks", futex_benchmarks },
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{ "all", "All benchmarks", NULL },
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{ NULL, NULL, NULL }
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};
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@ -12,6 +12,9 @@
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#ifndef __NR_perf_event_open
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# define __NR_perf_event_open 336
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#endif
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#ifndef __NR_futex
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# define __NR_futex 240
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#endif
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#endif
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#if defined(__x86_64__)
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@ -23,6 +26,9 @@
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#ifndef __NR_perf_event_open
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# define __NR_perf_event_open 298
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#endif
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#ifndef __NR_futex
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# define __NR_futex 202
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#endif
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#endif
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#ifdef __powerpc__
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