perf bench: Add futex-requeue microbenchmark (0fb298cf) · Commits · e / devices / android_kernel_oneplus_sm7250

tools/perf/Makefile.perf

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		@@ -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

tools/perf/bench/bench.h

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		@@ -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

tools/perf/bench/futex-requeue.c

0 → 100644

+211 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2013 Davidlohr Bueso <davidlohr@hp.com>
		*
		* 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 -- thus mimicking a regular futex_wait.
		*/

		#include "../perf.h"
		#include "../util/util.h"
		#include "../util/stat.h"
		#include "../util/parse-options.h"
		#include "../util/header.h"
		#include "bench.h"
		#include "futex.h"

		#include <err.h>
		#include <stdlib.h>
		#include <sys/time.h>
		#include <pthread.h>

		static u_int32_t futex1 = 0, futex2 = 0;

		/*
		* How many tasks to requeue at a time.
		* Default to 1 in order to make the kernel work more.
		*/
		static unsigned int nrequeue = 1;

		/*
		* There can be significant variance from run to run,
		* the more repeats, the more exact the overall avg and
		* the better idea of the futex latency.
		*/
		static unsigned int repeat = 10;

		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 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('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_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);
		threads_starting--;
		if (!threads_starting)
		pthread_cond_signal(&thread_parent);
		pthread_cond_wait(&thread_worker, &thread_lock);
		pthread_mutex_unlock(&thread_lock);

		futex_wait(&futex1, 0, NULL, FUTEX_PRIVATE_FLAG);
		return NULL;
		}

		static void block_threads(pthread_t *w,
		pthread_attr_t thread_attr)
		{
		cpu_set_t cpu;
		unsigned int i;

		threads_starting = nthreads;

		/* create and block all threads */
		for (i = 0; i < nthreads; i++) {
		CPU_ZERO(&cpu);
		CPU_SET(i % ncpus, &cpu);

		if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu))
		err(EXIT_FAILURE, "pthread_attr_setaffinity_np");

		if (pthread_create(&w[i], &thread_attr, workerfn, NULL))
		err(EXIT_FAILURE, "pthread_create");
		}
		}

		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,
		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_requeue_usage, 0);
		if (argc)
		goto err;

		ncpus = sysconf(_SC_NPROCESSORS_ONLN);

		sigfillset(&act.sa_mask);
		act.sa_sigaction = toggle_done;
		sigaction(SIGINT, &act, NULL);

		if (!nthreads)
		nthreads = ncpus;

		worker = calloc(nthreads, sizeof(*worker));
		if (!worker)
		err(EXIT_FAILURE, "calloc");

		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(&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 nrequeued = 0;
		struct timeval start, end, runtime;

		/* create, launch & block all threads */
		block_threads(worker, thread_attr);

		/* make sure all threads are already blocked */
		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);

		usleep(100000);

		/* Ok, all threads are patiently blocked, start requeueing */
		gettimeofday(&start, NULL);
		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(&requeued_stats, nrequeued);
		update_stats(&requeuetime_stats, runtime.tv_usec);

		if (!silent) {
		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)
		err(EXIT_FAILURE, "pthread_join");
		}

		}

		/* cleanup & report results */
		pthread_cond_destroy(&thread_parent);
		pthread_cond_destroy(&thread_worker);
		pthread_mutex_destroy(&thread_lock);
		pthread_attr_destroy(&thread_attr);

		print_summary();

		free(worker);
		return ret;
		err:
		usage_with_options(bench_futex_requeue_usage, options);
		exit(EXIT_FAILURE);
		}

tools/perf/bench/futex.h

+13 −0

Original line number	Diff line number	Diff line
		@@ -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 */

tools/perf/builtin-bench.c

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		@@ -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 }
		};