Commit-ID: 0fb298cf95c0d8119557b7d4657724a146e0622e Gitweb: http://git.kernel.org/tip/0fb298cf95c0d8119557b7d4657724a146e0622e Author: Davidlohr Bueso <davidl...@hp.com> AuthorDate: Sat, 14 Dec 2013 20:31:57 -0800 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Fri, 14 Mar 2014 11:20:44 -0300
perf bench: Add futex-requeue microbenchmark Block a bunch of threads on a futex and requeue them on another, N at a time. This program is particularly useful to measure the latency of nthread requeues without waking up any tasks -- thus mimicking a regular futex_wait. An example run: $ perf bench futex requeue -r 100 -t 64 Run summary [PID 151011]: Requeuing 64 threads (from 0x7d15c4 to 0x7d15c8), 1 at a time. [Run 1]: Requeued 64 of 64 threads in 0.0400 ms [Run 2]: Requeued 64 of 64 threads in 0.0390 ms [Run 3]: Requeued 64 of 64 threads in 0.0400 ms ... [Run 100]: Requeued 64 of 64 threads in 0.0390 ms Requeued 64 of 64 threads in 0.0399 ms (+-0.37%) Signed-off-by: Davidlohr Bueso <davidl...@hp.com> Acked-by: Darren Hart <dvh...@linux.intel.com> Cc: Aswin Chandramouleeswaran <as...@hp.com> Cc: Darren Hart <dvh...@linux.intel.com> Cc: Ingo Molnar <mi...@redhat.com> Cc: Jason Low <jason.l...@hp.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Scott J Norton <scott.nor...@hp.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Waiman Long <waiman.l...@hp.com> Link: http://lkml.kernel.org/r/1387081917-9102-4-git-send-email-davidl...@hp.com Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/Makefile.perf | 1 + tools/perf/bench/bench.h | 1 + tools/perf/bench/{futex-wake.c => futex-requeue.c} | 108 +++++++++++---------- tools/perf/bench/futex.h | 13 +++ tools/perf/builtin-bench.c | 1 + 5 files changed, 75 insertions(+), 49 deletions(-) diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index 6fa5d8b..50d875d 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -428,6 +428,7 @@ BUILTIN_OBJS += $(OUTPUT)bench/mem-memcpy.o BUILTIN_OBJS += $(OUTPUT)bench/mem-memset.o BUILTIN_OBJS += $(OUTPUT)bench/futex-hash.o BUILTIN_OBJS += $(OUTPUT)bench/futex-wake.o +BUILTIN_OBJS += $(OUTPUT)bench/futex-requeue.o BUILTIN_OBJS += $(OUTPUT)builtin-diff.o BUILTIN_OBJS += $(OUTPUT)builtin-evlist.o diff --git a/tools/perf/bench/bench.h b/tools/perf/bench/bench.h index 6ac3f1d..eba4670 100644 --- a/tools/perf/bench/bench.h +++ b/tools/perf/bench/bench.h @@ -33,6 +33,7 @@ extern int bench_mem_memcpy(int argc, const char **argv, extern int bench_mem_memset(int argc, const char **argv, const char *prefix); extern int bench_futex_hash(int argc, const char **argv, const char *prefix); extern int bench_futex_wake(int argc, const char **argv, const char *prefix); +extern int bench_futex_requeue(int argc, const char **argv, const char *prefix); #define BENCH_FORMAT_DEFAULT_STR "default" #define BENCH_FORMAT_DEFAULT 0 diff --git a/tools/perf/bench/futex-wake.c b/tools/perf/bench/futex-requeue.c similarity index 57% copy from tools/perf/bench/futex-wake.c copy to tools/perf/bench/futex-requeue.c index d096169..a1625587 100644 --- a/tools/perf/bench/futex-wake.c +++ b/tools/perf/bench/futex-requeue.c @@ -1,11 +1,11 @@ /* * Copyright (C) 2013 Davidlohr Bueso <davidl...@hp.com> * - * futex-wake: Block a bunch of threads on a futex and wake'em up, N at a time. + * 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 wakeups - * in non-error situations: all waiters are queued and all wake calls wakeup - * one or more tasks, and thus the waitqueue is never empty. + * This program is particularly useful to measure the latency of nthread + * requeues without waking up any tasks -- thus mimicking a regular futex_wait. */ #include "../perf.h" @@ -21,14 +21,13 @@ #include <sys/time.h> #include <pthread.h> -/* all threads will block on the same futex */ -static u_int32_t futex1 = 0; +static u_int32_t futex1 = 0, futex2 = 0; /* - * How many wakeups to do at a time. + * How many tasks to requeue at a time. * Default to 1 in order to make the kernel work more. */ -static unsigned int nwakes = 1; +static unsigned int nrequeue = 1; /* * There can be significant variance from run to run, @@ -37,26 +36,39 @@ static unsigned int nwakes = 1; */ static unsigned int repeat = 10; -pthread_t *worker; +static pthread_t *worker; static bool done = 0, silent = 0; static pthread_mutex_t thread_lock; static pthread_cond_t thread_parent, thread_worker; -static struct stats waketime_stats, wakeup_stats; +static struct stats requeuetime_stats, requeued_stats; static unsigned int ncpus, threads_starting, nthreads = 0; static const struct option options[] = { - OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"), - OPT_UINTEGER('w', "nwakes", &nwakes, "Specify amount of threads to wake at once"), - OPT_UINTEGER('r', "repeat", &repeat, "Specify amount of times to repeat the run"), - OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"), + OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"), + OPT_UINTEGER('q', "nrequeue", &nrequeue, "Specify amount of threads to requeue at once"), + OPT_UINTEGER('r', "repeat", &repeat, "Specify amount of times to repeat the run"), + OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"), OPT_END() }; -static const char * const bench_futex_wake_usage[] = { - "perf bench futex wake <options>", +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, + nthreads, + requeuetime_avg/1e3, + rel_stddev_stats(requeuetime_stddev, requeuetime_avg)); +} + static void *workerfn(void *arg __maybe_unused) { pthread_mutex_lock(&thread_lock); @@ -70,19 +82,6 @@ static void *workerfn(void *arg __maybe_unused) return NULL; } -static void print_summary(void) -{ - double waketime_avg = avg_stats(&waketime_stats); - double waketime_stddev = stddev_stats(&waketime_stats); - unsigned int wakeup_avg = avg_stats(&wakeup_stats); - - printf("Wokeup %d of %d threads in %.4f ms (+-%.2f%%)\n", - wakeup_avg, - nthreads, - waketime_avg/1e3, - rel_stddev_stats(waketime_stddev, waketime_avg)); -} - static void block_threads(pthread_t *w, pthread_attr_t thread_attr) { @@ -111,19 +110,17 @@ static void toggle_done(int sig __maybe_unused, done = true; } -int bench_futex_wake(int argc, const char **argv, - const char *prefix __maybe_unused) +int bench_futex_requeue(int argc, const char **argv, + const char *prefix __maybe_unused) { int ret = 0; unsigned int i, j; struct sigaction act; pthread_attr_t thread_attr; - argc = parse_options(argc, argv, options, bench_futex_wake_usage, 0); - if (argc) { - usage_with_options(bench_futex_wake_usage, options); - exit(EXIT_FAILURE); - } + argc = parse_options(argc, argv, options, bench_futex_requeue_usage, 0); + if (argc) + goto err; ncpus = sysconf(_SC_NPROCESSORS_ONLN); @@ -138,19 +135,19 @@ int bench_futex_wake(int argc, const char **argv, if (!worker) err(EXIT_FAILURE, "calloc"); - printf("Run summary [PID %d]: blocking on %d threads (at futex %p), " - "waking up %d at a time.\n\n", - getpid(), nthreads, &futex1, nwakes); + printf("Run summary [PID %d]: Requeuing %d threads (from %p to %p), " + "%d at a time.\n\n", + getpid(), nthreads, &futex1, &futex2, nrequeue); - init_stats(&wakeup_stats); - init_stats(&waketime_stats); + init_stats(&requeued_stats); + init_stats(&requeuetime_stats); pthread_attr_init(&thread_attr); pthread_mutex_init(&thread_lock, NULL); pthread_cond_init(&thread_parent, NULL); pthread_cond_init(&thread_worker, NULL); for (j = 0; j < repeat && !done; j++) { - unsigned int nwoken = 0; + unsigned int nrequeued = 0; struct timeval start, end, runtime; /* create, launch & block all threads */ @@ -165,21 +162,31 @@ int bench_futex_wake(int argc, const char **argv, usleep(100000); - /* Ok, all threads are patiently blocked, start waking folks up */ + /* Ok, all threads are patiently blocked, start requeueing */ gettimeofday(&start, NULL); - while (nwoken != nthreads) - nwoken += futex_wake(&futex1, nwakes, FUTEX_PRIVATE_FLAG); + for (nrequeued = 0; nrequeued < nthreads; nrequeued += nrequeue) + /* + * Do not wakeup any tasks blocked on futex1, allowing + * us to really measure futex_wait functionality. + */ + futex_cmp_requeue(&futex1, 0, &futex2, 0, nrequeue, + FUTEX_PRIVATE_FLAG); gettimeofday(&end, NULL); timersub(&end, &start, &runtime); - update_stats(&wakeup_stats, nwoken); - update_stats(&waketime_stats, runtime.tv_usec); + update_stats(&requeued_stats, nrequeued); + update_stats(&requeuetime_stats, runtime.tv_usec); if (!silent) { - printf("[Run %d]: Wokeup %d of %d threads in %.4f ms\n", - j + 1, nwoken, nthreads, runtime.tv_usec/1e3); + printf("[Run %d]: Requeued %d of %d threads in %.4f ms\n", + j + 1, nrequeued, nthreads, runtime.tv_usec/1e3); } + /* everybody should be blocked on futex2, wake'em up */ + nrequeued = futex_wake(&futex2, nthreads, FUTEX_PRIVATE_FLAG); + if (nthreads != nrequeued) + warnx("couldn't wakeup all tasks (%d/%d)", nrequeued, nthreads); + for (i = 0; i < nthreads; i++) { ret = pthread_join(worker[i], NULL); if (ret) @@ -198,4 +205,7 @@ int bench_futex_wake(int argc, const char **argv, free(worker); return ret; +err: + usage_with_options(bench_futex_requeue_usage, options); + exit(EXIT_FAILURE); } diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h index 6ac4509..71f2844 100644 --- a/tools/perf/bench/futex.h +++ b/tools/perf/bench/futex.h @@ -55,4 +55,17 @@ futex_wake(u_int32_t *uaddr, int nr_wake, int opflags) return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags); } +/** +* futex_cmp_requeue() - requeue tasks from uaddr to uaddr2 +* @nr_wake: wake up to this many tasks +* @nr_requeue: requeue up to this many tasks +*/ +static inline int +futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake, + int nr_requeue, int opflags) +{ + return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2, + val, opflags); +} + #endif /* _FUTEX_H */ diff --git a/tools/perf/builtin-bench.c b/tools/perf/builtin-bench.c index 743a30a..f600b74 100644 --- a/tools/perf/builtin-bench.c +++ b/tools/perf/builtin-bench.c @@ -58,6 +58,7 @@ static struct bench mem_benchmarks[] = { static struct bench futex_benchmarks[] = { { "hash", "Benchmark for futex hash table", bench_futex_hash }, { "wake", "Benchmark for futex wake calls", bench_futex_wake }, + { "requeue", "Benchmark for futex requeue calls", bench_futex_requeue }, { "all", "Test all futex benchmarks", NULL }, { NULL, NULL, NULL } }; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
