From a043971141f163f9845324a2f83502d15011485d Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Sat, 14 Dec 2013 20:31:55 -0800 Subject: 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 Acked-by: Darren Hart Cc: Aswin Chandramouleeswaran Cc: Darren Hart Cc: Ingo Molnar Cc: Jason Low Cc: Peter Zijlstra Cc: Scott J Norton Cc: Thomas Gleixner Cc: Waiman Long Link: http://lkml.kernel.org/r/1387081917-9102-2-git-send-email-davidlohr@hp.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Makefile.perf | 1 + tools/perf/bench/bench.h | 1 + tools/perf/bench/futex-hash.c | 212 ++++++++++++++++++++++++++++++++++++++++++ tools/perf/bench/futex.h | 48 ++++++++++ tools/perf/builtin-bench.c | 10 +- tools/perf/perf.h | 6 ++ 6 files changed, 277 insertions(+), 1 deletion(-) create mode 100644 tools/perf/bench/futex-hash.c create mode 100644 tools/perf/bench/futex.h (limited to 'tools/perf') diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index 1f7ec48ac95..54ae547b4bc 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -426,6 +426,7 @@ BUILTIN_OBJS += $(OUTPUT)bench/mem-memset-x86-64-asm.o endif BUILTIN_OBJS += $(OUTPUT)bench/mem-memcpy.o BUILTIN_OBJS += $(OUTPUT)bench/mem-memset.o +BUILTIN_OBJS += $(OUTPUT)bench/futex-hash.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 0fdc85269c4..34edb5c34db 100644 --- a/tools/perf/bench/bench.h +++ b/tools/perf/bench/bench.h @@ -31,6 +31,7 @@ extern int bench_sched_pipe(int argc, const char **argv, const char *prefix); extern int bench_mem_memcpy(int argc, const char **argv, const char *prefix __maybe_unused); 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); #define BENCH_FORMAT_DEFAULT_STR "default" #define BENCH_FORMAT_DEFAULT 0 diff --git a/tools/perf/bench/futex-hash.c b/tools/perf/bench/futex-hash.c new file mode 100644 index 00000000000..a84206e9c4a --- /dev/null +++ b/tools/perf/bench/futex-hash.c @@ -0,0 +1,212 @@ +/* + * Copyright (C) 2013 Davidlohr Bueso + * + * futex-hash: Stress the hell out of the Linux kernel futex uaddr hashing. + * + * This program is particularly useful for measuring the kernel's futex hash + * table/function implementation. In order for it to make sense, use with as + * many threads and futexes as possible. + */ + +#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 +#include +#include +#include + +static unsigned int nthreads = 0; +static unsigned int nsecs = 10; +/* amount of futexes per thread */ +static unsigned int nfutexes = 1024; +static bool fshared = false, done = false, silent = false; + +struct timeval start, end, runtime; +static pthread_mutex_t thread_lock; +static unsigned int threads_starting; +static struct stats throughput_stats; +static pthread_cond_t thread_parent, thread_worker; + +struct worker { + int tid; + u_int32_t *futex; + pthread_t thread; + unsigned long ops; +}; + +static const struct option options[] = { + OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"), + OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"), + OPT_UINTEGER('f', "futexes", &nfutexes, "Specify amount of futexes per 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_hash_usage[] = { + "perf bench futex hash ", + NULL +}; + +static void *workerfn(void *arg) +{ + int ret; + unsigned int i; + struct worker *w = (struct worker *) arg; + + 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); + + do { + for (i = 0; i < nfutexes; i++, w->ops++) { + /* + * We want the futex calls to fail in order to stress + * the hashing of uaddr and not measure other steps, + * such as internal waitqueue handling, thus enlarging + * the critical region protected by hb->lock. + */ + ret = futex_wait(&w->futex[i], 1234, NULL, + fshared ? 0 : FUTEX_PRIVATE_FLAG); + if (!silent && + (!ret || errno != EAGAIN || errno != EWOULDBLOCK)) + warn("Non-expected futex return call"); + } + } while (!done); + + return NULL; +} + +static void toggle_done(int sig __maybe_unused, + siginfo_t *info __maybe_unused, + void *uc __maybe_unused) +{ + /* inform all threads that we're done for the day */ + done = true; + gettimeofday(&end, NULL); + timersub(&end, &start, &runtime); +} + +static void print_summary(void) +{ + unsigned long avg = avg_stats(&throughput_stats); + double stddev = stddev_stats(&throughput_stats); + + printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n", + !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg), + (int) runtime.tv_sec); +} + +int bench_futex_hash(int argc, const char **argv, + const char *prefix __maybe_unused) +{ + int ret = 0; + cpu_set_t cpu; + struct sigaction act; + unsigned int i, ncpus; + pthread_attr_t thread_attr; + struct worker *worker = NULL; + + argc = parse_options(argc, argv, options, bench_futex_hash_usage, 0); + if (argc) { + usage_with_options(bench_futex_hash_usage, options); + exit(EXIT_FAILURE); + } + + ncpus = sysconf(_SC_NPROCESSORS_ONLN); + + sigfillset(&act.sa_mask); + act.sa_sigaction = toggle_done; + sigaction(SIGINT, &act, NULL); + + if (!nthreads) /* default to the number of CPUs */ + nthreads = ncpus; + + worker = calloc(nthreads, sizeof(*worker)); + if (!worker) + goto errmem; + + printf("Run summary [PID %d]: %d threads, each operating on %d [%s] futexes for %d secs.\n\n", + getpid(), nthreads, nfutexes, fshared ? "shared":"private", nsecs); + + init_stats(&throughput_stats); + pthread_mutex_init(&thread_lock, NULL); + pthread_cond_init(&thread_parent, NULL); + pthread_cond_init(&thread_worker, NULL); + + threads_starting = nthreads; + pthread_attr_init(&thread_attr); + gettimeofday(&start, NULL); + for (i = 0; i < nthreads; i++) { + worker[i].tid = i; + worker[i].futex = calloc(nfutexes, sizeof(*worker[i].futex)); + if (!worker[i].futex) + goto errmem; + + CPU_ZERO(&cpu); + CPU_SET(i % ncpus, &cpu); + + ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu); + if (ret) + err(EXIT_FAILURE, "pthread_attr_setaffinity_np"); + + ret = pthread_create(&worker[i].thread, &thread_attr, workerfn, + (void *)(struct worker *) &worker[i]); + if (ret) + err(EXIT_FAILURE, "pthread_create"); + + } + pthread_attr_destroy(&thread_attr); + + 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); + + sleep(nsecs); + toggle_done(0, NULL, NULL); + + for (i = 0; i < nthreads; i++) { + ret = pthread_join(worker[i].thread, 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); + + for (i = 0; i < nthreads; i++) { + unsigned long t = worker[i].ops/runtime.tv_sec; + update_stats(&throughput_stats, t); + if (!silent) { + if (nfutexes == 1) + printf("[thread %2d] futex: %p [ %ld ops/sec ]\n", + worker[i].tid, &worker[i].futex[0], t); + else + printf("[thread %2d] futexes: %p ... %p [ %ld ops/sec ]\n", + worker[i].tid, &worker[i].futex[0], + &worker[i].futex[nfutexes-1], t); + } + + free(worker[i].futex); + } + + print_summary(); + + free(worker); + return ret; +errmem: + err(EXIT_FAILURE, "calloc"); +} diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h new file mode 100644 index 00000000000..7d0bda543e3 --- /dev/null +++ b/tools/perf/bench/futex.h @@ -0,0 +1,48 @@ +/* + * Glibc independent futex library for testing kernel functionality. + * Shamelessly stolen from Darren Hart + * http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/ + */ + +#ifndef _FUTEX_H +#define _FUTEX_H + +#include +#include +#include +#include + +/** + * futex() - SYS_futex syscall wrapper + * @uaddr: address of first futex + * @op: futex op code + * @val: typically expected value of uaddr, but varies by op + * @timeout: typically an absolute struct timespec (except where noted + * otherwise). Overloaded by some ops + * @uaddr2: address of second futex for some ops\ + * @val3: varies by op + * @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG + * + * futex() is used by all the following futex op wrappers. It can also be + * used for misuse and abuse testing. Generally, the specific op wrappers + * should be used instead. It is a macro instead of an static inline function as + * some of the types over overloaded (timeout is used for nr_requeue for + * example). + * + * These argument descriptions are the defaults for all + * like-named arguments in the following wrappers except where noted below. + */ +#define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \ + syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3) + +/** + * futex_wait() - block on uaddr with optional timeout + * @timeout: relative timeout + */ +static inline int +futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags) +{ + return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags); +} + +#endif /* _FUTEX_H */ diff --git a/tools/perf/builtin-bench.c b/tools/perf/builtin-bench.c index e47f90cc7b9..a8b0138fc6a 100644 --- a/tools/perf/builtin-bench.c +++ b/tools/perf/builtin-bench.c @@ -12,6 +12,7 @@ * sched ... scheduler and IPC performance * mem ... memory access performance * numa ... NUMA scheduling and MM performance + * futex ... Futex performance */ #include "perf.h" #include "util/util.h" @@ -54,6 +55,12 @@ static struct bench mem_benchmarks[] = { { NULL, NULL, NULL } }; +static struct bench futex_benchmarks[] = { + { "hash", "Benchmark for futex hash table", bench_futex_hash }, + { "all", "Test all futex benchmarks", NULL }, + { NULL, NULL, NULL } +}; + struct collection { const char *name; const char *summary; @@ -61,11 +68,12 @@ struct collection { }; static struct collection collections[] = { - { "sched", "Scheduler and IPC benchmarks", sched_benchmarks }, + { "sched", "Scheduler and IPC benchmarks", sched_benchmarks }, { "mem", "Memory access benchmarks", mem_benchmarks }, #ifdef HAVE_LIBNUMA_SUPPORT { "numa", "NUMA scheduling and MM benchmarks", numa_benchmarks }, #endif + {"futex", "Futex stressing benchmarks", futex_benchmarks }, { "all", "All benchmarks", NULL }, { NULL, NULL, NULL } }; diff --git a/tools/perf/perf.h b/tools/perf/perf.h index 6898ad0e199..e18a8b5e695 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -12,6 +12,9 @@ #ifndef __NR_perf_event_open # define __NR_perf_event_open 336 #endif +#ifndef __NR_futex +# define __NR_futex 240 +#endif #endif #if defined(__x86_64__) @@ -23,6 +26,9 @@ #ifndef __NR_perf_event_open # define __NR_perf_event_open 298 #endif +#ifndef __NR_futex +# define __NR_futex 202 +#endif #endif #ifdef __powerpc__ -- cgit v1.2.3-70-g09d2