[PATCH v4 14/15] perf bench: Add futex2 benchmark tests

André Almeida
2021-06-03T20:01:40Z

Add support at the existing futex benchmarking code base to enable
futex2 calls. `perf bench` tests can be used not only as a way to
measure the performance of implementation, but also as stress testing
for the kernel infrastructure.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
---
tools/arch/x86/include/asm/unistd_64.h | 12 ++++++
tools/perf/bench/bench.h | 4 ++
tools/perf/bench/futex-hash.c | 24 +++++++++--
tools/perf/bench/futex-requeue.c | 57 ++++++++++++++++++++------
tools/perf/bench/futex-wake-parallel.c | 41 +++++++++++++++---
tools/perf/bench/futex-wake.c | 37 +++++++++++++----
tools/perf/bench/futex.h | 47 +++++++++++++++++++++
tools/perf/builtin-bench.c | 18 ++++++--
8 files changed, 206 insertions(+), 34 deletions(-)

diff --git a/tools/arch/x86/include/asm/unistd_64.h b/tools/arch/x86/include/asm/unistd_64.h
index 4205ed4158bf..191d43d84f04 100644
--- a/tools/arch/x86/include/asm/unistd_64.h
+++ b/tools/arch/x86/include/asm/unistd_64.h
@@ -17,3 +17,15 @@
#ifndef __NR_setns
#define __NR_setns 308
#endif
+
+#ifndef __NR_futex_wait
+# define __NR_futex_wait 447
+#endif
+
+#ifndef __NR_futex_wake
+# define __NR_futex_wake 448
+#endif
+
+#ifndef __NR_futex_requeue
+# define __NR_futex_requeue 450
+#endif
diff --git a/tools/perf/bench/bench.h b/tools/perf/bench/bench.h
index eac36afab2b3..12346844b354 100644
--- a/tools/perf/bench/bench.h
+++ b/tools/perf/bench/bench.h
@@ -38,9 +38,13 @@ int bench_mem_memcpy(int argc, const char **argv);
int bench_mem_memset(int argc, const char **argv);
int bench_mem_find_bit(int argc, const char **argv);
int bench_futex_hash(int argc, const char **argv);
+int bench_futex2_hash(int argc, const char **argv);
int bench_futex_wake(int argc, const char **argv);
+int bench_futex2_wake(int argc, const char **argv);
int bench_futex_wake_parallel(int argc, const char **argv);
+int bench_futex2_wake_parallel(int argc, const char **argv);
int bench_futex_requeue(int argc, const char **argv);
+int bench_futex2_requeue(int argc, const char **argv);
/* pi futexes */
int bench_futex_lock_pi(int argc, const char **argv);
int bench_epoll_wait(int argc, const char **argv);
diff --git a/tools/perf/bench/futex-hash.c b/tools/perf/bench/futex-hash.c
index b65373ce5c4f..1068749af40c 100644
--- a/tools/perf/bench/futex-hash.c
+++ b/tools/perf/bench/futex-hash.c
@@ -33,7 +33,7 @@ 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;
+static bool fshared = false, done = false, silent = false, futex2 = false;
static int futex_flag = 0;

struct timeval bench__start, bench__end, bench__runtime;
@@ -85,7 +85,10 @@ static void *workerfn(void *arg)
* such as internal waitqueue handling, thus enlarging
* the critical region protected by hb->lock.
*/
- ret = futex_wait(&w->futex[i], 1234, NULL, futex_flag);
+ if (!futex2)
+ ret = futex_wait(&w->futex[i], 1234, NULL, futex_flag);
+ else
+ ret = futex2_wait(&w->futex[i], 1234, futex_flag, NULL);
if (!silent &&
(!ret || errno != EAGAIN || errno != EWOULDBLOCK))
warn("Non-expected futex return call");
@@ -116,7 +119,7 @@ static void print_summary(void)
(int)bench__runtime.tv_sec);
}

-int bench_futex_hash(int argc, const char **argv)
+static int __bench_futex_hash(int argc, const char **argv)
{
int ret = 0;
cpu_set_t cpuset;
@@ -148,7 +151,9 @@ int bench_futex_hash(int argc, const char **argv)
if (!worker)
goto errmem;

- if (!fshared)
+ if (futex2)
+ futex_flag = FUTEX_32 | (fshared * FUTEX_SHARED_FLAG);
+ else if (!fshared)
futex_flag = FUTEX_PRIVATE_FLAG;

printf("Run summary [PID %d]: %d threads, each operating on %d [%s] futexes for %d secs.\n\n",
@@ -228,3 +233,14 @@ int bench_futex_hash(int argc, const char **argv)
errmem:
err(EXIT_FAILURE, "calloc");
}
+
+int bench_futex_hash(int argc, const char **argv)
+{
+ return __bench_futex_hash(argc, argv);
+}
+
+int bench_futex2_hash(int argc, const char **argv)
+{
+ futex2 = true;
+ return __bench_futex_hash(argc, argv);
+}
diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c
index 5fa23295ee5f..6cdd649b54f4 100644
--- a/tools/perf/bench/futex-requeue.c
+++ b/tools/perf/bench/futex-requeue.c
@@ -2,8 +2,8 @@
/*
* 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.
+ * futex-requeue: Block a bunch of threads on addr1 and requeue them
+ * on addr2, 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.
@@ -28,7 +28,10 @@
#include <stdlib.h>
#include <sys/time.h>

-static u_int32_t futex1 = 0, futex2 = 0;
+static u_int32_t addr1 = 0, addr2 = 0;
+
+static struct futex_requeue rq1 = { .uaddr = &addr1, .flags = FUTEX_32 };
+static struct futex_requeue rq2 = { .uaddr = &addr2, .flags = FUTEX_32 };

/*
* How many tasks to requeue at a time.
@@ -37,7 +40,7 @@ static u_int32_t futex1 = 0, futex2 = 0;
static unsigned int nrequeue = 1;

static pthread_t *worker;
-static bool done = false, silent = false, fshared = false;
+static bool done = false, silent = false, fshared = false, futex2 = false;
static pthread_mutex_t thread_lock;
static pthread_cond_t thread_parent, thread_worker;
static struct stats requeuetime_stats, requeued_stats;
@@ -79,7 +82,11 @@ static void *workerfn(void *arg __maybe_unused)
pthread_cond_wait(&thread_worker, &thread_lock);
pthread_mutex_unlock(&thread_lock);

- futex_wait(&futex1, 0, NULL, futex_flag);
+ if (!futex2)
+ futex_wait(&addr1, 0, NULL, futex_flag);
+ else
+ futex2_wait(&addr1, 0, futex_flag, NULL);
+
return NULL;
}

@@ -111,7 +118,7 @@ static void toggle_done(int sig __maybe_unused,
done = true;
}

-int bench_futex_requeue(int argc, const char **argv)
+static int __bench_futex_requeue(int argc, const char **argv)
{
int ret = 0;
unsigned int i, j;
@@ -139,15 +146,20 @@ int bench_futex_requeue(int argc, const char **argv)
if (!worker)
err(EXIT_FAILURE, "calloc");

- if (!fshared)
+ if (futex2) {
+ futex_flag = FUTEX_32 | (fshared * FUTEX_SHARED_FLAG);
+ rq1.flags |= FUTEX_SHARED_FLAG * fshared;
+ rq2.flags |= FUTEX_SHARED_FLAG * fshared;
+ } else if (!fshared) {
futex_flag = FUTEX_PRIVATE_FLAG;
+ }

if (nrequeue > nthreads)
nrequeue = nthreads;

printf("Run summary [PID %d]: Requeuing %d threads (from [%s] %p to %p), "
"%d at a time.\n\n", getpid(), nthreads,
- fshared ? "shared":"private", &futex1, &futex2, nrequeue);
+ fshared ? "shared":"private", &addr1, &addr2, nrequeue);

init_stats(&requeued_stats);
init_stats(&requeuetime_stats);
@@ -176,11 +188,15 @@ int bench_futex_requeue(int argc, const char **argv)
gettimeofday(&start, NULL);
while (nrequeued < nthreads) {
/*
- * Do not wakeup any tasks blocked on futex1, allowing
+ * Do not wakeup any tasks blocked on addr1, allowing
* us to really measure futex_wait functionality.
*/
- nrequeued += futex_cmp_requeue(&futex1, 0, &futex2, 0,
- nrequeue, futex_flag);
+ if (!futex2)
+ nrequeued += futex_cmp_requeue(&addr1, 0, &addr2,
+ 0, nrequeue, futex_flag);
+ else
+ nrequeued += futex2_requeue(&rq1, &rq2,
+ 0, nrequeue, 0, 0);
}

gettimeofday(&end, NULL);
@@ -194,8 +210,12 @@ int bench_futex_requeue(int argc, const char **argv)
j + 1, nrequeued, nthreads, runtime.tv_usec / (double)USEC_PER_MSEC);
}

- /* everybody should be blocked on futex2, wake'em up */
- nrequeued = futex_wake(&futex2, nrequeued, futex_flag);
+ /* everybody should be blocked on addr2, wake'em up */
+ if (!futex2)
+ nrequeued = futex_wake(&addr2, nrequeued, futex_flag);
+ else
+ nrequeued = futex2_wake(&addr2, nrequeued, futex_flag);
+
if (nthreads != nrequeued)
warnx("couldn't wakeup all tasks (%d/%d)", nrequeued, nthreads);

@@ -220,3 +240,14 @@ int bench_futex_requeue(int argc, const char **argv)
usage_with_options(bench_futex_requeue_usage, options);
exit(EXIT_FAILURE);
}
+
+int bench_futex_requeue(int argc, const char **argv)
+{
+ return __bench_futex_requeue(argc, argv);
+}
+
+int bench_futex2_requeue(int argc, const char **argv)
+{
+ futex2 = true;
+ return __bench_futex_requeue(argc, argv);
+}
diff --git a/tools/perf/bench/futex-wake-parallel.c b/tools/perf/bench/futex-wake-parallel.c
index 6e6f5247e1fe..cac90fc0bfb3 100644
--- a/tools/perf/bench/futex-wake-parallel.c
+++ b/tools/perf/bench/futex-wake-parallel.c
@@ -17,6 +17,12 @@ int bench_futex_wake_parallel(int argc __maybe_unused, const char **argv __maybe
pr_err("%s: pthread_barrier_t unavailable, disabling this test...\n", __func__);
return 0;
}
+
+int bench_futex2_wake_parallel(int argc __maybe_unused, const char **argv __maybe_unused)
+{
+ pr_err("%s: pthread_barrier_t unavailable, disabling this test...\n", __func__);
+ return 0;
+}
#else /* HAVE_PTHREAD_BARRIER */
/* For the CLR_() macros */
#include <string.h>
@@ -47,7 +53,7 @@ static unsigned int nwakes = 1;
static u_int32_t futex = 0;

static pthread_t *blocked_worker;
-static bool done = false, silent = false, fshared = false;
+static bool done = false, silent = false, fshared = false, futex2 = false;
static unsigned int nblocked_threads = 0, nwaking_threads = 0;
static pthread_mutex_t thread_lock;
static pthread_cond_t thread_parent, thread_worker;
@@ -78,7 +84,11 @@ static void *waking_workerfn(void *arg)

gettimeofday(&start, NULL);

- waker->nwoken = futex_wake(&futex, nwakes, futex_flag);
+ if (!futex2)
+ waker->nwoken = futex_wake(&futex, nwakes, futex_flag);
+ else
+ waker->nwoken = futex2_wake(&futex, nwakes, futex_flag);
+
if (waker->nwoken != nwakes)
warnx("couldn't wakeup all tasks (%d/%d)",
waker->nwoken, nwakes);
@@ -129,8 +139,13 @@ static void *blocked_workerfn(void *arg __maybe_unused)
pthread_mutex_unlock(&thread_lock);

while (1) { /* handle spurious wakeups */
- if (futex_wait(&futex, 0, NULL, futex_flag) != EINTR)
- break;
+ if (!futex2) {
+ if (futex_wait(&futex, 0, NULL, futex_flag) != EINTR)
+ break;
+ } else {
+ if (futex2_wait(&futex, 0, futex_flag, NULL) != EINTR)
+ break;
+ }
}

pthread_exit(NULL);
@@ -217,7 +232,7 @@ static void toggle_done(int sig __maybe_unused,
done = true;
}

-int bench_futex_wake_parallel(int argc, const char **argv)
+static int __bench_futex_wake_parallel(int argc, const char **argv)
{
int ret = 0;
unsigned int i, j;
@@ -261,7 +276,9 @@ int bench_futex_wake_parallel(int argc, const char **argv)
if (!blocked_worker)
err(EXIT_FAILURE, "calloc");

- if (!fshared)
+ if (futex2)
+ futex_flag = FUTEX_32 | (fshared * FUTEX_SHARED_FLAG);
+ else if (!fshared)
futex_flag = FUTEX_PRIVATE_FLAG;

printf("Run summary [PID %d]: blocking on %d threads (at [%s] "
@@ -321,4 +338,16 @@ int bench_futex_wake_parallel(int argc, const char **argv)
free(blocked_worker);
return ret;
}
+
+int bench_futex_wake_parallel(int argc, const char **argv)
+{
+ return __bench_futex_wake_parallel(argc, argv);
+}
+
+int bench_futex2_wake_parallel(int argc, const char **argv)
+{
+ futex2 = true;
+ return __bench_futex_wake_parallel(argc, argv);
+}
+
#endif /* HAVE_PTHREAD_BARRIER */
diff --git a/tools/perf/bench/futex-wake.c b/tools/perf/bench/futex-wake.c
index 6d217868f53c..546d2818eed8 100644
--- a/tools/perf/bench/futex-wake.c
+++ b/tools/perf/bench/futex-wake.c
@@ -38,7 +38,7 @@ static u_int32_t futex1 = 0;
static unsigned int nwakes = 1;

pthread_t *worker;
-static bool done = false, silent = false, fshared = false;
+static bool done = false, silent = false, fshared = false, futex2 = false;
static pthread_mutex_t thread_lock;
static pthread_cond_t thread_parent, thread_worker;
static struct stats waketime_stats, wakeup_stats;
@@ -68,8 +68,13 @@ static void *workerfn(void *arg __maybe_unused)
pthread_mutex_unlock(&thread_lock);

while (1) {
- if (futex_wait(&futex1, 0, NULL, futex_flag) != EINTR)
- break;
+ if (!futex2) {
+ if (futex_wait(&futex1, 0, NULL, futex_flag) != EINTR)
+ break;
+ } else {
+ if (futex2_wait(&futex1, 0, futex_flag, NULL) != EINTR)
+ break;
+ }
}

pthread_exit(NULL);
@@ -117,7 +122,7 @@ static void toggle_done(int sig __maybe_unused,
done = true;
}

-int bench_futex_wake(int argc, const char **argv)
+static int __bench_futex_wake(int argc, const char **argv)
{
int ret = 0;
unsigned int i, j;
@@ -147,7 +152,9 @@ int bench_futex_wake(int argc, const char **argv)
if (!worker)
err(EXIT_FAILURE, "calloc");

- if (!fshared)
+ if (futex2)
+ futex_flag = FUTEX_32 | (fshared * FUTEX_SHARED_FLAG);
+ else if (!fshared)
futex_flag = FUTEX_PRIVATE_FLAG;

printf("Run summary [PID %d]: blocking on %d threads (at [%s] futex %p), "
@@ -179,9 +186,14 @@ int bench_futex_wake(int argc, const char **argv)

/* Ok, all threads are patiently blocked, start waking folks up */
gettimeofday(&start, NULL);
- while (nwoken != nthreads)
- nwoken += futex_wake(&futex1, nwakes, futex_flag);
+ while (nwoken != nthreads) {
+ if (!futex2)
+ nwoken += futex_wake(&futex1, nwakes, futex_flag);
+ else
+ nwoken += futex2_wake(&futex1, nwakes, futex_flag);
+ }
gettimeofday(&end, NULL);
+
timersub(&end, &start, &runtime);

update_stats(&wakeup_stats, nwoken);
@@ -211,3 +223,14 @@ int bench_futex_wake(int argc, const char **argv)
free(worker);
return ret;
}
+
+int bench_futex_wake(int argc, const char **argv)
+{
+ return __bench_futex_wake(argc, argv);
+}
+
+int bench_futex2_wake(int argc, const char **argv)
+{
+ futex2 = true;
+ return __bench_futex_wake(argc, argv);
+}
diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h
index 31b53cc7d5bc..6b2213cf3f64 100644
--- a/tools/perf/bench/futex.h
+++ b/tools/perf/bench/futex.h
@@ -86,4 +86,51 @@ futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wak
return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
val, opflags);
}
+
+/**
+ * futex2_wait - Wait at uaddr if *uaddr == val, until timo.
+ * @uaddr: User address to wait for
+ * @val: Expected value at uaddr
+ * @flags: Operation options
+ * @timo: Optional timeout
+ *
+ * Return: 0 on success, error code otherwise
+ */
+static inline int futex2_wait(volatile void *uaddr, unsigned long val,
+ unsigned long flags, struct timespec *timo)
+{
+ return syscall(__NR_futex_wait, uaddr, val, flags, timo);
+}
+
+/**
+ * futex2_wake - Wake a number of waiters waiting at uaddr
+ * @uaddr: Address to wake
+ * @nr: Number of waiters to wake
+ * @flags: Operation options
+ *
+ * Return: number of waked futexes
+ */
+static inline int futex2_wake(volatile void *uaddr, unsigned int nr, unsigned long flags)
+{
+ return syscall(__NR_futex_wake, uaddr, nr, flags);
+}
+
+/**
+ * futex2_requeue - Requeue waiters from an address to another one
+ * @uaddr1: Address where waiters are currently waiting on
+ * @uaddr2: New address to wait
+ * @nr_wake: Number of waiters at uaddr1 to be wake
+ * @nr_requeue: After waking nr_wake, number of waiters to be requeued
+ * @cmpval: Expected value at uaddr1
+ * @flags: Operation options
+ *
+ * Return: waked futexes + requeued futexes at uaddr1
+ */
+static inline int futex2_requeue(volatile struct futex_requeue *uaddr1,
+ volatile struct futex_requeue *uaddr2,
+ unsigned int nr_wake, unsigned int nr_requeue,
+ unsigned int cmpval, unsigned long flags)
+{
+ return syscall(__NR_futex_requeue, uaddr1, uaddr2, nr_wake, nr_requeue, cmpval, flags);
+}
#endif /* _FUTEX_H */
diff --git a/tools/perf/builtin-bench.c b/tools/perf/builtin-bench.c
index 62a7b7420a44..e41a95ad2db6 100644
--- a/tools/perf/builtin-bench.c
+++ b/tools/perf/builtin-bench.c
@@ -12,10 +12,11 @@
*
* sched ... scheduler and IPC performance
* syscall ... System call performance
- * mem ... memory access performance
- * numa ... NUMA scheduling and MM performance
- * futex ... Futex performance
- * epoll ... Event poll performance
+ * mem ... memory access performance
+ * numa ... NUMA scheduling and MM performance
+ * futex ... Futex performance
+ * futex2 ... Futex2 performance
+ * epoll ... Event poll performance
*/
#include <subcmd/parse-options.h>
#include "builtin.h"
@@ -75,6 +76,14 @@ static struct bench futex_benchmarks[] = {
{ NULL, NULL, NULL }
};

+static struct bench futex2_benchmarks[] = {
+ { "hash", "Benchmark for futex2 hash table", bench_futex2_hash },
+ { "wake", "Benchmark for futex2 wake calls", bench_futex2_wake },
+ { "wake-parallel", "Benchmark for parallel futex2 wake calls", bench_futex2_wake_parallel },
+ { "requeue", "Benchmark for futex2 requeue calls", bench_futex2_requeue },
+ { NULL, NULL, NULL }
+};
+
#ifdef HAVE_EVENTFD_SUPPORT
static struct bench epoll_benchmarks[] = {
{ "wait", "Benchmark epoll concurrent epoll_waits", bench_epoll_wait },
@@ -105,6 +114,7 @@ static struct collection collections[] = {
{ "numa", "NUMA scheduling and MM benchmarks", numa_benchmarks },
#endif
{"futex", "Futex stressing benchmarks", futex_benchmarks },
+ {"futex2", "Futex2 stressing benchmarks", futex2_benchmarks },
#ifdef HAVE_EVENTFD_SUPPORT
{"epoll", "Epoll stressing benchmarks", epoll_benchmarks },
#endif
--
2.31.1