perf bench futex: Support operations for shared futexes

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>

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);