perf bench futex: Support parallel waker threads (d65817b4) · Commits · e / devices / android_kernel_teracube_emerald

tools/perf/Documentation/perf-bench.txt

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		@@ -210,6 +210,9 @@ Suite for evaluating hash tables.
		wake::
		Suite for evaluating wake calls.

		wake-parallel::
		Suite for evaluating parallel wake calls.

		requeue::
		Suite for evaluating requeue calls.

tools/perf/bench/Build

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		@@ -3,6 +3,7 @@ perf-y += sched-pipe.o
		perf-y += mem-memcpy.o
		perf-y += futex-hash.o
		perf-y += futex-wake.o
		perf-y += futex-wake-parallel.o
		perf-y += futex-requeue.o

		perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-asm.o

tools/perf/bench/bench.h

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		@@ -33,6 +33,8 @@ 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_wake_parallel(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"

tools/perf/bench/futex-wake-parallel.c

0 → 100644

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Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2015 Davidlohr Bueso.
		*
		* Block a bunch of threads and let parallel waker threads wakeup an
		* equal amount of them. The program output reflects the avg latency
		* for each individual thread to service its share of work. Ultimately
		* it can be used to measure futex_wake() changes.
		*/

		#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>

		struct thread_data {
		pthread_t worker;
		unsigned int nwoken;
		struct timeval runtime;
		};

		static unsigned int nwakes = 1;

		/* all threads will block on the same futex -- hash bucket chaos ;) */
		static u_int32_t futex = 0;

		static pthread_t *blocked_worker;
		static bool done = false, silent = false, fshared = false;
		static unsigned int nblocked_threads = 0, nwaking_threads = 0;
		static pthread_mutex_t thread_lock;
		static pthread_cond_t thread_parent, thread_worker;
		static struct stats waketime_stats, wakeup_stats;
		static unsigned int ncpus, threads_starting;
		static int futex_flag = 0;

		static const struct option options[] = {
		OPT_UINTEGER('t', "threads", &nblocked_threads, "Specify amount of threads"),
		OPT_UINTEGER('w', "nwakers", &nwaking_threads, "Specify amount of waking 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"),
		OPT_END()
		};

		static const char * const bench_futex_wake_parallel_usage[] = {
		"perf bench futex wake-parallel <options>",
		NULL
		};

		static void waking_workerfn(void arg)
		{
		struct thread_data waker = (struct thread_data ) arg;
		struct timeval start, end;

		gettimeofday(&start, NULL);

		waker->nwoken = futex_wake(&futex, nwakes, futex_flag);
		if (waker->nwoken != nwakes)
		warnx("couldn't wakeup all tasks (%d/%d)",
		waker->nwoken, nwakes);

		gettimeofday(&end, NULL);
		timersub(&end, &start, &waker->runtime);

		pthread_exit(NULL);
		return NULL;
		}

		static void wakeup_threads(struct thread_data *td, pthread_attr_t thread_attr)
		{
		unsigned int i;

		pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_JOINABLE);

		/* create and block all threads */
		for (i = 0; i < nwaking_threads; i++) {
		/*
		* Thread creation order will impact per-thread latency
		* as it will affect the order to acquire the hb spinlock.
		* For now let the scheduler decide.
		*/
		if (pthread_create(&td[i].worker, &thread_attr,
		waking_workerfn, (void *)&td[i]))
		err(EXIT_FAILURE, "pthread_create");
		}

		for (i = 0; i < nwaking_threads; i++)
		if (pthread_join(td[i].worker, NULL))
		err(EXIT_FAILURE, "pthread_join");
		}

		static void blocked_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);

		while (1) { /* handle spurious wakeups */
		if (futex_wait(&futex, 0, NULL, futex_flag) != EINTR)
		break;
		}

		pthread_exit(NULL);
		return NULL;
		}

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

		threads_starting = nblocked_threads;

		/* create and block all threads */
		for (i = 0; i < nblocked_threads; 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, blocked_workerfn, NULL))
		err(EXIT_FAILURE, "pthread_create");
		}
		}

		static void print_run(struct thread_data *waking_worker, unsigned int run_num)
		{
		unsigned int i, wakeup_avg;
		double waketime_avg, waketime_stddev;
		struct stats __waketime_stats, __wakeup_stats;

		init_stats(&__wakeup_stats);
		init_stats(&__waketime_stats);

		for (i = 0; i < nwaking_threads; i++) {
		update_stats(&__waketime_stats, waking_worker[i].runtime.tv_usec);
		update_stats(&__wakeup_stats, waking_worker[i].nwoken);
		}

		waketime_avg = avg_stats(&__waketime_stats);
		waketime_stddev = stddev_stats(&__waketime_stats);
		wakeup_avg = avg_stats(&__wakeup_stats);

		printf("[Run %d]: Avg per-thread latency (waking %d/%d threads) "
		"in %.4f ms (+-%.2f%%)\n", run_num + 1, wakeup_avg,
		nblocked_threads, waketime_avg/1e3,
		rel_stddev_stats(waketime_stddev, waketime_avg));
		}

		static void print_summary(void)
		{
		unsigned int wakeup_avg;
		double waketime_avg, waketime_stddev;

		waketime_avg = avg_stats(&waketime_stats);
		waketime_stddev = stddev_stats(&waketime_stats);
		wakeup_avg = avg_stats(&wakeup_stats);

		printf("Avg per-thread latency (waking %d/%d threads) in %.4f ms (+-%.2f%%)\n",
		wakeup_avg,
		nblocked_threads,
		waketime_avg/1e3,
		rel_stddev_stats(waketime_stddev, waketime_avg));
		}


		static void do_run_stats(struct thread_data *waking_worker)
		{
		unsigned int i;

		for (i = 0; i < nwaking_threads; i++) {
		update_stats(&waketime_stats, waking_worker[i].runtime.tv_usec);
		update_stats(&wakeup_stats, waking_worker[i].nwoken);
		}

		}

		static void toggle_done(int sig __maybe_unused,
		siginfo_t *info __maybe_unused,
		void *uc __maybe_unused)
		{
		done = true;
		}

		int bench_futex_wake_parallel(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;
		struct thread_data *waking_worker;

		argc = parse_options(argc, argv, options,
		bench_futex_wake_parallel_usage, 0);
		if (argc) {
		usage_with_options(bench_futex_wake_parallel_usage, options);
		exit(EXIT_FAILURE);
		}

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

		ncpus = sysconf(_SC_NPROCESSORS_ONLN);
		if (!nblocked_threads)
		nblocked_threads = ncpus;

		/* some sanity checks */
		if (nwaking_threads > nblocked_threads \|\| !nwaking_threads)
		nwaking_threads = nblocked_threads;

		if (nblocked_threads % nwaking_threads)
		errx(EXIT_FAILURE, "Must be perfectly divisible");
		/*
		* Each thread will wakeup nwakes tasks in
		* a single futex_wait call.
		*/
		nwakes = nblocked_threads/nwaking_threads;

		blocked_worker = calloc(nblocked_threads, sizeof(*blocked_worker));
		if (!blocked_worker)
		err(EXIT_FAILURE, "calloc");

		if (!fshared)
		futex_flag = FUTEX_PRIVATE_FLAG;

		printf("Run summary [PID %d]: blocking on %d threads (at [%s] "
		"futex %p), %d threads waking up %d at a time.\n\n",
		getpid(), nblocked_threads, fshared ? "shared":"private",
		&futex, nwaking_threads, nwakes);

		init_stats(&wakeup_stats);
		init_stats(&waketime_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 < bench_repeat && !done; j++) {
		waking_worker = calloc(nwaking_threads, sizeof(*waking_worker));
		if (!waking_worker)
		err(EXIT_FAILURE, "calloc");

		/* create, launch & block all threads */
		block_threads(blocked_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 waking folks up */
		wakeup_threads(waking_worker, thread_attr);

		for (i = 0; i < nblocked_threads; i++) {
		ret = pthread_join(blocked_worker[i], NULL);
		if (ret)
		err(EXIT_FAILURE, "pthread_join");
		}

		do_run_stats(waking_worker);
		if (!silent)
		print_run(waking_worker, j);

		free(waking_worker);
		}

		/* 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(blocked_worker);
		return ret;
		}

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 },
		{ "wake-parallel", "Benchmark for parallel futex wake calls", bench_futex_wake_parallel },
		{ "requeue", "Benchmark for futex requeue calls", bench_futex_requeue },
		{ "all", "Test all futex benchmarks", NULL },
		{ NULL, NULL, NULL }