This microbenchmark simulates how the use of different futex types
can affect the actual performanace of userspace mutex locks. The
usage is:
perf bench futex mutex <options>
Three sets of simple mutex lock and unlock functions are implemented
using the wait-wake, PI and TP futexes respectively. This
microbenchmark then runs the locking rate measurement tests using
either one of those mutexes or all of them consecutively.
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
tools/perf/bench/Build | 1 +
tools/perf/bench/bench.h | 1 +
tools/perf/bench/futex-locks.c | 844 +++++++++++++++++++++++++++++++++++++++++
tools/perf/bench/futex.h | 23 ++
tools/perf/builtin-bench.c | 10 +
tools/perf/check-headers.sh | 4 +
6 files changed, 883 insertions(+)
create mode 100644 tools/perf/bench/futex-locks.c
diff --git a/tools/perf/bench/Build b/tools/perf/bench/Build
index 60bf119..7ce1cd7 100644
--- a/tools/perf/bench/Build
+++ b/tools/perf/bench/Build
@@ -6,6 +6,7 @@ perf-y += futex-wake.o
perf-y += futex-wake-parallel.o
perf-y += futex-requeue.o
perf-y += futex-lock-pi.o
+perf-y += futex-locks.o
perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-asm.o
perf-$(CONFIG_X86_64) += mem-memset-x86-64-asm.o
diff --git a/tools/perf/bench/bench.h b/tools/perf/bench/bench.h
index 579a592..b0632df 100644
--- a/tools/perf/bench/bench.h
+++ b/tools/perf/bench/bench.h
@@ -36,6 +36,7 @@
int bench_futex_requeue(int argc, const char **argv, const char *prefix);
/* pi futexes */
int bench_futex_lock_pi(int argc, const char **argv, const char *prefix);
+int bench_futex_mutex(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-locks.c b/tools/perf/bench/futex-locks.c
new file mode 100644
index 0000000..ec1e627
--- /dev/null
+++ b/tools/perf/bench/futex-locks.c
@@ -0,0 +1,844 @@
+/*
+ * Copyright (C) 2016 Waiman Long <longman@xxxxxxxxxx>
+ *
+ * This microbenchmark simulates how the use of different futex types can
+ * affect the actual performanace of userspace locking primitives like mutex.
+ *
+ * The raw throughput of the futex lock and unlock calls is not a good
+ * indication of actual throughput of the mutex code as it may not really
+ * need to call into the kernel. Therefore, 3 sets of simple mutex lock and
+ * unlock functions are written to implenment a mutex lock using the
+ * wait-wake, PI and TP futexes respectively. These functions serve as the
+ * basis for measuring the locking throughput.
+ */
+
+#include <pthread.h>
+
+#include <signal.h>
+#include <string.h>
+#include "../util/stat.h"
+#include "../perf-sys.h"
+#include <subcmd/parse-options.h>
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <errno.h>
+#include "bench.h"
+#include "futex.h"
+
+#include <err.h>
+#include <stdlib.h>
+#include <sys/time.h>
+
+#define CACHELINE_SIZE 64
+#define gettid() syscall(SYS_gettid)
+#define __cacheline_aligned __attribute__((__aligned__(CACHELINE_SIZE)))
+
+typedef u32 futex_t;
+typedef void (*lock_fn_t)(futex_t *futex, int tid);
+typedef void (*unlock_fn_t)(futex_t *futex, int tid);
+
+/*
+ * Statistical count list
+ */
+enum {
+ STAT_OPS, /* # of exclusive locking operations */
+ STAT_LOCKS, /* # of exclusive lock futex calls */
+ STAT_UNLOCKS, /* # of exclusive unlock futex calls */
+ STAT_SLEEPS, /* # of exclusive lock sleeps */
+ STAT_EAGAINS, /* # of EAGAIN errors */
+ STAT_WAKEUPS, /* # of wakeups (unlock return) */
+ STAT_HANDOFFS, /* # of lock handoff (TP only) */
+ STAT_STEALS, /* # of lock steals (TP only) */
+ STAT_LOCKERRS, /* # of exclusive lock errors */
+ STAT_UNLKERRS, /* # of exclusive unlock errors */
+ STAT_NUM /* Total # of statistical count */
+};
+
+/*
+ * Syscall time list
+ */
+enum {
+ TIME_LOCK, /* Total exclusive lock syscall time */
+ TIME_UNLK, /* Total exclusive unlock syscall time */
+ TIME_NUM,
+};
+
+struct worker {
+ futex_t *futex;
+ pthread_t thread;
+
+ /*
+ * Per-thread operation statistics
+ */
+ u32 stats[STAT_NUM];
+
+ /*
+ * Lock/unlock times
+ */
+ u64 times[TIME_NUM];
+} __cacheline_aligned;
+
+/*
+ * Global cache-aligned futex
+ */
+static futex_t __cacheline_aligned global_futex;
+static futex_t *pfutex = &global_futex;
+
+static __thread futex_t thread_id; /* Thread ID */
+static __thread int counter; /* Sleep counter */
+
+static struct worker *worker, *worker_alloc;
+static unsigned int nsecs = 10;
+static bool verbose, done, fshared, exit_now, timestat;
+static unsigned int ncpus, nthreads;
+static int flags;
+static const char *ftype;
+static int loadlat = 1;
+static int locklat = 1;
+static int wratio;
+struct timeval start, end, runtime;
+static unsigned int worker_start;
+static unsigned int threads_starting;
+static unsigned int threads_stopping;
+static struct stats throughput_stats;
+static lock_fn_t mutex_lock_fn;
+static unlock_fn_t mutex_unlock_fn;
+
+/*
+ * Lock/unlock syscall time macro
+ */
+static inline void systime_add(int tid, int item, struct timespec *begin,
+ struct timespec *_end)
+{
+ worker[tid].times[item] += (_end->tv_sec - begin->tv_sec)*1000000000 +
+ _end->tv_nsec - begin->tv_nsec;
+}
+
+static inline double stat_percent(struct worker *w, int top, int bottom)
+{
+ return (double)w->stats[top] * 100 / w->stats[bottom];
+}
+
+/*
+ * Inline functions to update the statistical counts
+ *
+ * Enable statistics collection may sometimes impact the locking rates
+ * to be measured. So we can specify the DISABLE_STAT macro to disable
+ * statistic counts collection for all except the core locking rate counts.
+ *
+ * #define DISABLE_STAT
+ */
+#ifndef DISABLE_STAT
+static inline void stat_add(int tid, int item, int num)
+{
+ worker[tid].stats[item] += num;
+}
+
+static inline void stat_inc(int tid, int item)
+{
+ stat_add(tid, item, 1);
+}
+#else
+static inline void stat_add(int tid __maybe_unused, int item __maybe_unused,
+ int num __maybe_unused)
+{
+}
+
+static inline void stat_inc(int tid __maybe_unused, int item __maybe_unused)
+{
+}
+#endif
+
+/*
+ * The latency value within a lock critical section (load) and between locking
+ * operations is in term of the number of cpu_relax() calls that are being
+ * issued.
+ */
+static const struct option mutex_options[] = {
+ OPT_INTEGER ('d', "locklat", &locklat, "Specify inter-locking latency (default = 1)"),
+ OPT_STRING ('f', "ftype", &ftype, "type", "Specify futex type: WW, PI, TP, all (default)"),
+ OPT_INTEGER ('L', "loadlat", &loadlat, "Specify load latency (default = 1)"),
+ OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds, default = 10s)"),
+ OPT_BOOLEAN ('S', "shared", &fshared, "Use shared futexes instead of private ones"),
+ OPT_BOOLEAN ('T', "timestat", ×tat, "Track lock/unlock syscall times"),
+ OPT_UINTEGER('t', "threads", &nthreads, "Specify number of threads, default = # of CPUs"),
+ OPT_BOOLEAN ('v', "verbose", &verbose, "Verbose mode: display thread-level details"),
+ OPT_INTEGER ('w', "wait-ratio", &wratio, "Specify <n>/1024 of load is 1us sleep, default = 0"),
+ OPT_END()
+};
+
+static const char * const bench_futex_mutex_usage[] = {
+ "perf bench futex mutex <options>",
+ NULL
+};
+
+/**
+ * futex_cmpxchg() - atomic compare and exchange
+ * @uaddr: The address of the futex to be modified
+ * @oldval: The expected value of the futex
+ * @newval: The new value to try and assign to the futex
+ *
+ * Implement cmpxchg using gcc atomic builtins.
+ *
+ * Return: the old futex value.
+ */
+static inline futex_t futex_cmpxchg(futex_t *uaddr, futex_t old, futex_t new)
+{
+ return __sync_val_compare_and_swap(uaddr, old, new);
+}
+
+/**
+ * futex_xchg() - atomic exchange
+ * @uaddr: The address of the futex to be modified
+ * @newval: The new value to assign to the futex
+ *
+ * Implement cmpxchg using gcc atomic builtins.
+ *
+ * Return: the old futex value.
+ */
+static inline futex_t futex_xchg(futex_t *uaddr, futex_t new)
+{
+ return __sync_lock_test_and_set(uaddr, new);
+}
+
+/**
+ * atomic_dec_return - atomically decrement & return the new value
+ * @uaddr: The address of the futex to be decremented
+ * Return: The new value
+ */
+static inline int atomic_dec_return(futex_t *uaddr)
+{
+ return __sync_sub_and_fetch(uaddr, 1);
+}
+
+/**
+ * atomic_inc_return - atomically increment & return the new value
+ * @uaddr: The address of the futex to be incremented
+ * Return: The new value
+ */
+static inline int atomic_inc_return(futex_t *uaddr)
+{
+ return __sync_add_and_fetch(uaddr, 1);
+}
+
+/**********************[ MUTEX lock/unlock functions ]*********************/
+
+/*
+ * Wait-wake futex lock/unlock functions (Glibc implementation)
+ * futex value: 0 - unlocked
+ * 1 - locked
+ * 2 - locked with waiters (contended)
+ */
+static void ww_mutex_lock(futex_t *futex, int tid)
+{
+ struct timespec stime, etime;
+ futex_t val = *futex;
+ int ret;
+
+ if (!val) {
+ val = futex_cmpxchg(futex, 0, 1);
+ if (val == 0)
+ return;
+ }
+
+ for (;;) {
+ if (val != 2) {
+ /*
+ * Force value to 2 to indicate waiter
+ */
+ val = futex_xchg(futex, 2);
+ if (val == 0)
+ return;
+ }
+ if (timestat) {
+ clock_gettime(CLOCK_REALTIME, &stime);
+ ret = futex_wait(futex, 2, NULL, flags);
+ clock_gettime(CLOCK_REALTIME, &etime);
+ systime_add(tid, TIME_LOCK, &stime, &etime);
+ } else {
+ ret = futex_wait(futex, 2, NULL, flags);
+ }
+
+ stat_inc(tid, STAT_LOCKS);
+ if (ret < 0) {
+ if (errno == EAGAIN)
+ stat_inc(tid, STAT_EAGAINS);
+ else
+ stat_inc(tid, STAT_LOCKERRS);
+ }
+
+ val = *futex;
+ }
+}
+
+static void ww_mutex_unlock(futex_t *futex, int tid)
+{
+ struct timespec stime, etime;
+ futex_t val;
+ int ret;
+
+ val = futex_xchg(futex, 0);
+
+ if (val == 2) {
+ stat_inc(tid, STAT_UNLOCKS);
+ if (timestat) {
+ clock_gettime(CLOCK_REALTIME, &stime);
+ ret = futex_wake(futex, 1, flags);
+ clock_gettime(CLOCK_REALTIME, &etime);
+ systime_add(tid, TIME_UNLK, &stime, &etime);
+ } else {
+ ret = futex_wake(futex, 1, flags);
+ }
+ if (ret < 0)
+ stat_inc(tid, STAT_UNLKERRS);
+ else
+ stat_add(tid, STAT_WAKEUPS, ret);
+ }
+}
+
+/*
+ * Alternate wait-wake futex lock/unlock functions with thread_id lock word
+ */
+static void ww2_mutex_lock(futex_t *futex, int tid)
+{
+ struct timespec stime, etime;
+ futex_t val = *futex;
+ int ret;
+
+ if (!val) {
+ val = futex_cmpxchg(futex, 0, thread_id);
+ if (val == 0)
+ return;
+ }
+
+ for (;;) {
+ /*
+ * Set the FUTEX_WAITERS bit, if not set yet.
+ */
+ while (!(val & FUTEX_WAITERS)) {
+ futex_t old;
+
+ if (!val) {
+ val = futex_cmpxchg(futex, 0, thread_id);
+ if (val == 0)
+ return;
+ continue;
+ }
+ old = futex_cmpxchg(futex, val, val | FUTEX_WAITERS);
+ if (old == val) {
+ val |= FUTEX_WAITERS;
+ break;
+ }
+ val = old;
+ }
+ if (timestat) {
+ clock_gettime(CLOCK_REALTIME, &stime);
+ ret = futex_wait(futex, val, NULL, flags);
+ clock_gettime(CLOCK_REALTIME, &etime);
+ systime_add(tid, TIME_LOCK, &stime, &etime);
+ } else {
+ ret = futex_wait(futex, val, NULL, flags);
+ }
+ stat_inc(tid, STAT_LOCKS);
+ if (ret < 0) {
+ if (errno == EAGAIN)
+ stat_inc(tid, STAT_EAGAINS);
+ else
+ stat_inc(tid, STAT_LOCKERRS);
+ }
+
+ val = *futex;
+ }
+}
+
+static void ww2_mutex_unlock(futex_t *futex, int tid)
+{
+ struct timespec stime, etime;
+ futex_t val;
+ int ret;
+
+ val = futex_xchg(futex, 0);
+
+ if ((val & FUTEX_TID_MASK) != thread_id)
+ stat_inc(tid, STAT_UNLKERRS);
+
+ if (val & FUTEX_WAITERS) {
+ stat_inc(tid, STAT_UNLOCKS);
+ if (timestat) {
+ clock_gettime(CLOCK_REALTIME, &stime);
+ ret = futex_wake(futex, 1, flags);
+ clock_gettime(CLOCK_REALTIME, &etime);
+ systime_add(tid, TIME_UNLK, &stime, &etime);
+ } else {
+ ret = futex_wake(futex, 1, flags);
+ }
+ if (ret < 0)
+ stat_inc(tid, STAT_UNLKERRS);
+ else
+ stat_add(tid, STAT_WAKEUPS, ret);
+ }
+}
+
+/*
+ * PI futex lock/unlock functions
+ */
+static void pi_mutex_lock(futex_t *futex, int tid)
+{
+ struct timespec stime, etime;
+ futex_t val;
+ int ret;
+
+ val = futex_cmpxchg(futex, 0, thread_id);
+ if (val == 0)
+ return;
+
+ /*
+ * Retry if an error happens
+ */
+ for (;;) {
+ if (timestat) {
+ clock_gettime(CLOCK_REALTIME, &stime);
+ ret = futex_lock_pi(futex, NULL, flags);
+ clock_gettime(CLOCK_REALTIME, &etime);
+ systime_add(tid, TIME_LOCK, &stime, &etime);
+ } else {
+ ret = futex_lock_pi(futex, NULL, flags);
+ }
+ stat_inc(tid, STAT_LOCKS);
+ if (ret >= 0)
+ break;
+ stat_inc(tid, STAT_LOCKERRS);
+ }
+}
+
+static void pi_mutex_unlock(futex_t *futex, int tid)
+{
+ struct timespec stime, etime;
+ futex_t val;
+ int ret;
+
+ val = futex_cmpxchg(futex, thread_id, 0);
+ if (val == thread_id)
+ return;
+
+ if (timestat) {
+ clock_gettime(CLOCK_REALTIME, &stime);
+ ret = futex_unlock_pi(futex, flags);
+ clock_gettime(CLOCK_REALTIME, &etime);
+ systime_add(tid, TIME_UNLK, &stime, &etime);
+ } else {
+ ret = futex_unlock_pi(futex, flags);
+ }
+ if (ret < 0)
+ stat_inc(tid, STAT_UNLKERRS);
+ else
+ stat_add(tid, STAT_WAKEUPS, ret);
+ stat_inc(tid, STAT_UNLOCKS);
+}
+
+/*
+ * TP futex lock/unlock functions
+ */
+static void tp_mutex_lock(futex_t *futex, int tid)
+{
+ struct timespec stime, etime;
+ futex_t val;
+ int ret;
+
+ val = futex_cmpxchg(futex, 0, thread_id);
+ if (val == 0)
+ return;
+
+ /*
+ * Retry if an error happens
+ */
+ for (;;) {
+ if (timestat) {
+ clock_gettime(CLOCK_REALTIME, &stime);
+ ret = futex_lock(futex, NULL, flags);
+ clock_gettime(CLOCK_REALTIME, &etime);
+ systime_add(tid, TIME_LOCK, &stime, &etime);
+ } else {
+ ret = futex_lock(futex, NULL, flags);
+ }
+ stat_inc(tid, STAT_LOCKS);
+ if (ret >= 0)
+ break;
+ stat_inc(tid, STAT_LOCKERRS);
+ }
+ /*
+ * Get # of sleeps & locking method
+ */
+ stat_add(tid, STAT_SLEEPS, ret >> 16);
+ ret &= 0xff;
+ if (!ret)
+ stat_inc(tid, STAT_STEALS);
+ else if (ret == 2)
+ stat_inc(tid, STAT_HANDOFFS);
+}
+
+static void tp_mutex_unlock(futex_t *futex, int tid)
+{
+ struct timespec stime, etime;
+ futex_t val;
+ int ret;
+
+ val = futex_cmpxchg(futex, thread_id, 0);
+ if (val == thread_id)
+ return;
+
+ if (timestat) {
+ clock_gettime(CLOCK_REALTIME, &stime);
+ ret = futex_unlock(futex, flags);
+ clock_gettime(CLOCK_REALTIME, &etime);
+ systime_add(tid, TIME_UNLK, &stime, &etime);
+ } else {
+ ret = futex_unlock(futex, flags);
+ }
+ stat_inc(tid, STAT_UNLOCKS);
+ if (ret < 0)
+ stat_inc(tid, STAT_UNLKERRS);
+ else
+ stat_add(tid, STAT_WAKEUPS, ret);
+}
+
+/**************************************************************************/
+
+/*
+ * Load function
+ */
+static inline void load(int tid)
+{
+ int n = loadlat;
+
+ /*
+ * Optionally does a 1us sleep instead if wratio is defined and
+ * is within bound.
+ */
+ if (wratio && (((counter++ + tid) & 0x3ff) < wratio)) {
+ usleep(1);
+ return;
+ }
+
+ while (n-- > 0)
+ cpu_relax();
+}
+
+static inline void csdelay(void)
+{
+ int n = locklat;
+
+ while (n-- > 0)
+ cpu_relax();
+}
+
+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);
+ if (sig)
+ exit_now = true;
+}
+
+static void *mutex_workerfn(void *arg)
+{
+ long tid = (long)arg;
+ struct worker *w = &worker[tid];
+ lock_fn_t lock_fn = mutex_lock_fn;
+ unlock_fn_t unlock_fn = mutex_unlock_fn;
+
+ thread_id = gettid();
+ counter = 0;
+
+ atomic_dec_return(&threads_starting);
+
+ /*
+ * Busy wait until asked to start
+ */
+ while (!worker_start)
+ cpu_relax();
+
+ do {
+ lock_fn(w->futex, tid);
+ load(tid);
+ unlock_fn(w->futex, tid);
+ w->stats[STAT_OPS]++; /* One more locking operation */
+ csdelay();
+ } while (!done);
+
+ if (verbose)
+ printf("[thread %3ld (%d)] exited.\n", tid, thread_id);
+ atomic_inc_return(&threads_stopping);
+ return NULL;
+}
+
+static void create_threads(struct worker *w, pthread_attr_t *thread_attr,
+ void *(*workerfn)(void *arg), long tid)
+{
+ cpu_set_t cpu;
+
+ /*
+ * Bind each thread to a CPU
+ */
+ CPU_ZERO(&cpu);
+ CPU_SET(tid % ncpus, &cpu);
+ w->futex = pfutex;
+
+ if (pthread_attr_setaffinity_np(thread_attr, sizeof(cpu_set_t), &cpu))
+ err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
+
+ if (pthread_create(&w->thread, thread_attr, workerfn, (void *)tid))
+ err(EXIT_FAILURE, "pthread_create");
+}
+
+static int futex_mutex_type(const char **ptype)
+{
+ const char *type = *ptype;
+
+ if (!strcasecmp(type, "WW")) {
+ *ptype = "WW";
+ mutex_lock_fn = ww_mutex_lock;
+ mutex_unlock_fn = ww_mutex_unlock;
+ } else if (!strcasecmp(type, "WW2")) {
+ *ptype = "WW2";
+ mutex_lock_fn = ww2_mutex_lock;
+ mutex_unlock_fn = ww2_mutex_unlock;
+ } else if (!strcasecmp(type, "PI")) {
+ *ptype = "PI";
+ mutex_lock_fn = pi_mutex_lock;
+ mutex_unlock_fn = pi_mutex_unlock;
+ } else if (!strcasecmp(type, "TP")) {
+ *ptype = "TP";
+ mutex_lock_fn = tp_mutex_lock;
+ mutex_unlock_fn = tp_mutex_unlock;
+
+ /*
+ * Check if TP futex is supported.
+ */
+ futex_unlock(&global_futex, 0);
+ if (errno == ENOSYS) {
+ fprintf(stderr,
+ "\nTP futexes are not supported by the kernel!\n");
+ return -1;
+ }
+ } else {
+ return -1;
+ }
+ return 0;
+}
+
+static void futex_test_driver(const char *futex_type,
+ int (*proc_type)(const char **ptype),
+ void *(*workerfn)(void *arg))
+{
+ u64 us;
+ int i, j;
+ struct worker total;
+ double avg, stddev;
+ pthread_attr_t thread_attr;
+
+ /*
+ * There is an extra blank line before the error counts to highlight
+ * them.
+ */
+ const char *desc[STAT_NUM] = {
+ [STAT_OPS] = "Total exclusive locking ops",
+ [STAT_LOCKS] = "Exclusive lock futex calls",
+ [STAT_UNLOCKS] = "Exclusive unlock futex calls",
+ [STAT_SLEEPS] = "Exclusive lock sleeps",
+ [STAT_WAKEUPS] = "Process wakeups",
+ [STAT_EAGAINS] = "EAGAIN lock errors",
+ [STAT_HANDOFFS] = "Lock handoffs",
+ [STAT_STEALS] = "Lock stealings",
+ [STAT_LOCKERRS] = "\nExclusive lock errors",
+ [STAT_UNLKERRS] = "\nExclusive unlock errors",
+ };
+
+ if (exit_now)
+ return;
+
+ if (proc_type(&futex_type) < 0) {
+ fprintf(stderr, "Unknown futex type '%s'!\n", futex_type);
+ exit(1);
+ }
+
+ printf("\n=====================================\n");
+ printf("[PID %d]: %d threads doing %s futex lockings (load=%d) for %d secs.\n\n",
+ getpid(), nthreads, futex_type, loadlat, nsecs);
+
+ init_stats(&throughput_stats);
+
+ *pfutex = 0;
+ done = false;
+ threads_starting = nthreads;
+ pthread_attr_init(&thread_attr);
+
+ for (i = 0; i < (int)nthreads; i++)
+ create_threads(&worker[i], &thread_attr, workerfn, i);
+
+ while (threads_starting)
+ usleep(1);
+
+ gettimeofday(&start, NULL);
+
+ /*
+ * Start the test
+ *
+ * Unlike the other futex benchmarks, this one uses busy waiting
+ * instead of pthread APIs to make sure that all the threads (except
+ * the one that shares CPU with the parent) will start more or less
+ * simultaineously.
+ */
+ atomic_inc_return(&worker_start);
+ sleep(nsecs);
+ toggle_done(0, NULL, NULL);
+
+ /*
+ * In verbose mode, we check if all the threads have been stopped
+ * after 1ms and report the status if some are still running.
+ */
+ if (verbose) {
+ usleep(1000);
+ if (threads_stopping != nthreads) {
+ printf("%d threads still running 1ms after timeout"
+ " - futex = 0x%x\n",
+ nthreads - threads_stopping, *pfutex);
+ /*
+ * If the threads are still running after 10s,
+ * go directly to statistics printing and exit.
+ */
+ for (i = 10; i > 0; i--) {
+ sleep(1);
+ if (threads_stopping == nthreads)
+ break;
+ }
+ if (!i) {
+ printf("*** Threads waiting ABORTED!! ***\n\n");
+ goto print_stat;
+ }
+ }
+ }
+
+ for (i = 0; i < (int)nthreads; i++) {
+ int ret = pthread_join(worker[i].thread, NULL);
+
+ if (ret)
+ err(EXIT_FAILURE, "pthread_join");
+ }
+
+print_stat:
+ pthread_attr_destroy(&thread_attr);
+
+ us = runtime.tv_sec * 1000000 + runtime.tv_usec;
+ memset(&total, 0, sizeof(total));
+ for (i = 0; i < (int)nthreads; i++) {
+ /*
+ * Get a rounded estimate of the # of locking ops/sec.
+ */
+ u64 tp = (u64)worker[i].stats[STAT_OPS] * 1000000 / us;
+
+ for (j = 0; j < STAT_NUM; j++)
+ total.stats[j] += worker[i].stats[j];
+
+ update_stats(&throughput_stats, tp);
+ if (verbose)
+ printf("[thread %3d] futex: %p [ %'ld ops/sec ]\n",
+ i, worker[i].futex, (long)tp);
+ }
+
+ avg = avg_stats(&throughput_stats);
+ stddev = stddev_stats(&throughput_stats);
+
+ printf("Locking statistics:\n");
+ printf("%-28s = %'.2fs\n", "Test run time", (double)us/1000000);
+ for (i = 0; i < STAT_NUM; i++)
+ if (total.stats[i])
+ printf("%-28s = %'d\n", desc[i], total.stats[i]);
+
+ if (timestat && total.times[TIME_LOCK]) {
+ printf("\nSyscall times:\n");
+ if (total.stats[STAT_LOCKS])
+ printf("Avg exclusive lock syscall = %'ldns\n",
+ total.times[TIME_LOCK]/total.stats[STAT_LOCKS]);
+ if (total.stats[STAT_UNLOCKS])
+ printf("Avg exclusive unlock syscall = %'ldns\n",
+ total.times[TIME_UNLK]/total.stats[STAT_UNLOCKS]);
+ }
+
+ printf("\nPercentages:\n");
+ if (total.stats[STAT_LOCKS])
+ printf("Exclusive lock futex calls = %.1f%%\n",
+ stat_percent(&total, STAT_LOCKS, STAT_OPS));
+ if (total.stats[STAT_UNLOCKS])
+ printf("Exclusive unlock futex calls = %.1f%%\n",
+ stat_percent(&total, STAT_UNLOCKS, STAT_OPS));
+ if (total.stats[STAT_EAGAINS])
+ printf("EAGAIN lock errors = %.1f%%\n",
+ stat_percent(&total, STAT_EAGAINS, STAT_LOCKS));
+ if (total.stats[STAT_WAKEUPS])
+ printf("Process wakeups = %.1f%%\n",
+ stat_percent(&total, STAT_WAKEUPS, STAT_UNLOCKS));
+
+ printf("\nPer-thread Locking Rates:\n");
+ printf("Avg = %'d ops/sec (+- %.2f%%)\n", (int)(avg + 0.5),
+ rel_stddev_stats(stddev, avg));
+ printf("Min = %'d ops/sec\n", (int)throughput_stats.min);
+ printf("Max = %'d ops/sec\n", (int)throughput_stats.max);
+
+ if (*pfutex != 0)
+ printf("\nResidual futex value = 0x%x\n", *pfutex);
+
+ /* Clear the workers area */
+ memset(worker, 0, sizeof(*worker) * nthreads);
+}
+
+int bench_futex_mutex(int argc, const char **argv,
+ const char *prefix __maybe_unused)
+{
+ struct sigaction act;
+
+ argc = parse_options(argc, argv, mutex_options,
+ bench_futex_mutex_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;
+
+ /*
+ * Since the allocated memory buffer may not be properly cacheline
+ * aligned, we need to allocate one more than needed and manually
+ * adjust array boundary to be cacheline aligned.
+ */
+ worker_alloc = calloc(nthreads + 1, sizeof(*worker));
+ if (!worker_alloc)
+ err(EXIT_FAILURE, "calloc");
+ worker = (void *)((unsigned long)&worker_alloc[1] &
+ ~(CACHELINE_SIZE - 1));
+
+ if (!fshared)
+ flags = FUTEX_PRIVATE_FLAG;
+
+ if (!ftype || !strcmp(ftype, "all")) {
+ futex_test_driver("WW", futex_mutex_type, mutex_workerfn);
+ futex_test_driver("PI", futex_mutex_type, mutex_workerfn);
+ futex_test_driver("TP", futex_mutex_type, mutex_workerfn);
+ } else {
+ futex_test_driver(ftype, futex_mutex_type, mutex_workerfn);
+ }
+ free(worker_alloc);
+ return 0;
+err:
+ usage_with_options(bench_futex_mutex_usage, mutex_options);
+ exit(EXIT_FAILURE);
+}
diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h
index ba7c735..be1eb7a 100644
--- a/tools/perf/bench/futex.h
+++ b/tools/perf/bench/futex.h
@@ -87,6 +87,29 @@
val, opflags);
}
+#ifndef FUTEX_LOCK
+#define FUTEX_LOCK 0xff /* Disable the use of TP futexes */
+#define FUTEX_UNLOCK 0xff
+#endif /* FUTEX_LOCK */
+
+/**
+ * futex_lock() - lock the TP futex
+ */
+static inline int
+futex_lock(u_int32_t *uaddr, struct timespec *timeout, int opflags)
+{
+ return futex(uaddr, FUTEX_LOCK, 0, timeout, NULL, 0, opflags);
+}
+
+/**
+ * futex_unlock() - unlock the TP futex
+ */
+static inline int
+futex_unlock(u_int32_t *uaddr, int opflags)
+{
+ return futex(uaddr, FUTEX_UNLOCK, 0, NULL, NULL, 0, opflags);
+}
+
#ifndef HAVE_PTHREAD_ATTR_SETAFFINITY_NP
#include <pthread.h>
static inline int pthread_attr_setaffinity_np(pthread_attr_t *attr,
diff --git a/tools/perf/builtin-bench.c b/tools/perf/builtin-bench.c
index a1cddc6..bf4418d 100644
--- a/tools/perf/builtin-bench.c
+++ b/tools/perf/builtin-bench.c
@@ -20,6 +20,7 @@
#include "builtin.h"
#include "bench/bench.h"
+#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -62,6 +63,7 @@ struct bench {
{ "requeue", "Benchmark for futex requeue calls", bench_futex_requeue },
/* pi-futexes */
{ "lock-pi", "Benchmark for futex lock_pi calls", bench_futex_lock_pi },
+ { "mutex", "Benchmark for mutex locks using futexes", bench_futex_mutex },
{ "all", "Run all futex benchmarks", NULL },
{ NULL, NULL, NULL }
};
@@ -215,6 +217,7 @@ int cmd_bench(int argc, const char **argv, const char *prefix __maybe_unused)
{
struct collection *coll;
int ret = 0;
+ char *locale;
if (argc < 2) {
/* No collection specified. */
@@ -222,6 +225,13 @@ int cmd_bench(int argc, const char **argv, const char *prefix __maybe_unused)
goto end;
}
+ /*
+ * Enable better number formatting.
+ */
+ locale = setlocale(LC_NUMERIC, "");
+ if (!strcmp(locale, "C"))
+ setlocale(LC_NUMERIC, "en_US");
+
argc = parse_options(argc, argv, bench_options, bench_usage,
PARSE_OPT_STOP_AT_NON_OPTION);
diff --git a/tools/perf/check-headers.sh b/tools/perf/check-headers.sh
index c747bfd..6ec5f2d 100755
--- a/tools/perf/check-headers.sh
+++ b/tools/perf/check-headers.sh
@@ -57,3 +57,7 @@ check arch/x86/lib/memcpy_64.S -B -I "^EXPORT_SYMBOL" -I "^#include <asm/
check arch/x86/lib/memset_64.S -B -I "^EXPORT_SYMBOL" -I "^#include <asm/export.h>"
check include/uapi/asm-generic/mman.h -B -I "^#include <\(uapi/\)*asm-generic/mman-common.h>"
check include/uapi/linux/mman.h -B -I "^#include <\(uapi/\)*asm/mman.h>"
+
+# need to link to the latest futex.h header
+[[ -f ../../include/uapi/linux/futex.h ]] &&
+ ln -sf ../../../../../include/uapi/linux/futex.h util/include/linux
--
1.8.3.1
--
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