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Subject[PATCH 3/8] perf bench futex: Support operations for shared futexes
Date
From: Davidlohr Bueso <dave@stgolabs.net>

Unlike futex-hash, requeuing and wakeup benchmarks do not support shared
futexes, limiting the usefulness of the programs. Correct this, and
allow using the local -S parameter. The default remains using private
futexes.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Link: http://lkml.kernel.org/r/1412008868-22328-1-git-send-email-dave@stgolabs.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/bench/futex-hash.c | 7 +++++--
tools/perf/bench/futex-requeue.c | 24 +++++++++++++++---------
tools/perf/bench/futex-wake.c | 15 ++++++++++-----
3 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/tools/perf/bench/futex-hash.c b/tools/perf/bench/futex-hash.c
index a84206e9c4aa..fc9bebd2cca0 100644
--- a/tools/perf/bench/futex-hash.c
+++ b/tools/perf/bench/futex-hash.c
@@ -26,6 +26,7 @@ static unsigned int nsecs = 10;
/* amount of futexes per thread */
static unsigned int nfutexes = 1024;
static bool fshared = false, done = false, silent = false;
+static int futex_flag = 0;

struct timeval start, end, runtime;
static pthread_mutex_t thread_lock;
@@ -75,8 +76,7 @@ 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,
- fshared ? 0 : FUTEX_PRIVATE_FLAG);
+ ret = futex_wait(&w->futex[i], 1234, NULL, futex_flag);
if (!silent &&
(!ret || errno != EAGAIN || errno != EWOULDBLOCK))
warn("Non-expected futex return call");
@@ -135,6 +135,9 @@ int bench_futex_hash(int argc, const char **argv,
if (!worker)
goto errmem;

+ 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",
getpid(), nthreads, nfutexes, fshared ? "shared":"private", nsecs);

diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c
index 732403bfd31a..9837a8831406 100644
--- a/tools/perf/bench/futex-requeue.c
+++ b/tools/perf/bench/futex-requeue.c
@@ -30,16 +30,18 @@ static u_int32_t futex1 = 0, futex2 = 0;
static unsigned int nrequeue = 1;

static pthread_t *worker;
-static bool done = 0, silent = 0;
+static bool done = false, silent = false, fshared = false;
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 int futex_flag = 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_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()
};

@@ -70,7 +72,7 @@ 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_PRIVATE_FLAG);
+ futex_wait(&futex1, 0, NULL, futex_flag);
return NULL;
}

@@ -127,9 +129,12 @@ int bench_futex_requeue(int argc, const char **argv,
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);
+ if (!fshared)
+ futex_flag = FUTEX_PRIVATE_FLAG;
+
+ 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);

init_stats(&requeued_stats);
init_stats(&requeuetime_stats);
@@ -156,13 +161,14 @@ int bench_futex_requeue(int argc, const char **argv,

/* Ok, all threads are patiently blocked, start requeueing */
gettimeofday(&start, NULL);
- for (nrequeued = 0; nrequeued < nthreads; nrequeued += nrequeue)
+ 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);
+ futex_cmp_requeue(&futex1, 0, &futex2, 0,
+ nrequeue, futex_flag);
+ }
gettimeofday(&end, NULL);
timersub(&end, &start, &runtime);

@@ -175,7 +181,7 @@ int bench_futex_requeue(int argc, const char **argv,
}

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

diff --git a/tools/perf/bench/futex-wake.c b/tools/perf/bench/futex-wake.c
index 50022cbce87e..929f762be47e 100644
--- a/tools/perf/bench/futex-wake.c
+++ b/tools/perf/bench/futex-wake.c
@@ -31,16 +31,18 @@ static u_int32_t futex1 = 0;
static unsigned int nwakes = 1;

pthread_t *worker;
-static bool done = false, silent = false;
+static bool done = false, silent = false, fshared = false;
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, nthreads = 0;
+static int futex_flag = 0;

static const struct option options[] = {
OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
OPT_UINTEGER('w', "nwakes", &nwakes, "Specify amount of threads to wake at once"),
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()
};

@@ -58,7 +60,7 @@ 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_PRIVATE_FLAG);
+ futex_wait(&futex1, 0, NULL, futex_flag);
return NULL;
}

@@ -130,9 +132,12 @@ int bench_futex_wake(int argc, const char **argv,
if (!worker)
err(EXIT_FAILURE, "calloc");

- printf("Run summary [PID %d]: blocking on %d threads (at futex %p), "
+ if (!fshared)
+ futex_flag = FUTEX_PRIVATE_FLAG;
+
+ printf("Run summary [PID %d]: blocking on %d threads (at [%s] futex %p), "
"waking up %d at a time.\n\n",
- getpid(), nthreads, &futex1, nwakes);
+ getpid(), nthreads, fshared ? "shared":"private", &futex1, nwakes);

init_stats(&wakeup_stats);
init_stats(&waketime_stats);
@@ -160,7 +165,7 @@ 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_PRIVATE_FLAG);
+ nwoken += futex_wake(&futex1, nwakes, futex_flag);
gettimeofday(&end, NULL);
timersub(&end, &start, &runtime);

--
1.9.3


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