[PATCH 4/6][BZ #11588] benchtests: Add benchmarks for pthread_cond_* functions

[Gratian Crisan <gratian dot crisan at ni dot com>]

Add a benchmark set that measures the average execution time, min, max, 
running
variance and standard deviation for:

 - N threads calling pthread_cond_signal/pthread_cond_broadcast w/o any 
waiters
consuming the signal.

 - time it takes to execute pthread_cond_signal/pthread_cond_broadcast in 
the
presence of a waiter.

 - round trip time from the ptread_cond_signal call to pthread_cond_wait 
or
pthread_cond_timedwait return for N threads.

 - round trip time from the ptread_cond_broadcast call to 
pthread_cond_wait or
pthread_cond_timedwait return for N threads.

Signed-off-by: Gratian Crisan <gratian.crisan@ni.com>

---
ChangeLog:

2014-07-07  Gratian Crisan  <gratian.crisan@ni.com>

        [BZ #11588]
        * benchtests/bench-pthread_cond.c: New file.
        * benchtests/Makefile: Add pthread_cond benchmark.
---
 benchtests/Makefile             |   5 +-
 benchtests/bench-pthread_cond.c | 389 
++++++++++++++++++++++++++++++++++++++++
 2 files changed, 393 insertions(+), 1 deletion(-)
 create mode 100644 benchtests/bench-pthread_cond.c

diff --git a/benchtests/Makefile b/benchtests/Makefile
index fd3036d..f2b5f4c 100644
--- a/benchtests/Makefile
+++ b/benchtests/Makefile
@@ -26,6 +26,7 @@ bench-math := acos acosh asin asinh atan atanh cos cosh 
exp exp2 ffs ffsll \
              log log2 modf pow rint sin sincos sinh sqrt tan tanh
 
 bench-pthread := pthread_once
+bench-pthread-set := pthread_cond
 
 bench := $(bench-math) $(bench-pthread)
 
@@ -39,13 +40,15 @@ string-bench-all := $(string-bench)
 
 stdlib-bench := strtod
 
-benchset := $(string-bench-all) $(stdlib-bench)
+benchset := $(string-bench-all) $(stdlib-bench) $(bench-pthread-set)
 
+CFLAGS-bench-pthread_cond.c += -g
 CFLAGS-bench-ffs.c += -fno-builtin
 CFLAGS-bench-ffsll.c += -fno-builtin
 
 $(addprefix $(objpfx)bench-,$(bench-math)): $(libm)
 $(addprefix $(objpfx)bench-,$(bench-pthread)): $(shared-thread-library)
+$(addprefix $(objpfx)bench-,$(bench-pthread-set)): 
$(shared-thread-library) $(libm)
 
 
 
diff --git a/benchtests/bench-pthread_cond.c 
b/benchtests/bench-pthread_cond.c
new file mode 100644
index 0000000..fd08a9b
--- /dev/null
+++ b/benchtests/bench-pthread_cond.c
@@ -0,0 +1,389 @@
+/* Measure the performance of pthread_cond_* family of functions.
+   Copyright (C) 2013-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+
+#include <error.h>
+#include <errno.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <sched.h>
+#include <time.h>
+#include <math.h>
+
+#include "bench-timing.h"
+
+typedef enum
+  {
+    COND_START,
+    COND_WAITING,
+    COND_SIGNALED,
+    COND_STOP
+  } state_t;
+
+/* Uncomment to run benchmarks at RT priority */
+/* #define REALTIME 1  */
+
+#define TIMEDWAIT_FLAG (1<<0)
+#define BROADCAST_FLAG (1<<1)
+#define ROUNDTRIP_FLAG (1<<2)
+
+typedef struct
+{
+  pthread_t tid;
+  pthread_cond_t cond;
+  pthread_mutex_t mutex;
+  volatile state_t state;
+  uint32_t flags;
+  size_t iters;
+  timing_t start;
+  timing_t stop;
+} params_t;
+
+typedef struct
+{
+  timing_t sum;
+  timing_t min;
+  timing_t max;
+  size_t n;
+  double rmean;
+  double rvar;
+} stats_t;
+
+static stats_t g_stats;
+static pthread_mutex_t g_stats_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static void
+init_stats (void)
+{
+  bzero (&g_stats, sizeof (stats_t));
+}
+
+static void
+update_stats (params_t *p)
+{
+  timing_t diff;
+  double delta;
+
+  pthread_mutex_lock (&g_stats_mutex);
+
+  g_stats.n++;
+  TIMING_DIFF (diff, p->start, p->stop);
+  TIMING_ACCUM (g_stats.sum, diff);
+  if (diff > g_stats.max)
+    g_stats.max = diff;
+  if (diff < g_stats.min || g_stats.min == 0)
+    g_stats.min = diff;
+  delta = diff - g_stats.rmean;
+  g_stats.rmean += delta / g_stats.n;
+  g_stats.rvar += delta * (diff - g_stats.rmean);
+
+  pthread_mutex_unlock (&g_stats_mutex);
+}
+
+static void
+print_stats (size_t niters, size_t nthreads)
+{
+  double variance;
+
+  variance = (g_stats.n > 1) ? g_stats.rvar/(g_stats.n - 1) : 0.0;
+
+  printf ("%-14u%-11u", (unsigned int) niters, (unsigned int) nthreads);
+  printf ("%-11g", (double) g_stats.sum / (double) g_stats.n);
+  printf ("%-8u%-12u", (unsigned int) g_stats.min, (unsigned int) 
g_stats.max);
+  printf ("%-15e%g\n", variance, sqrt (variance));
+}
+
+static void
+create_thread (params_t *p, void *(*function) (void *))
+{
+  pthread_attr_t attr;
+  pthread_condattr_t cond_attr;
+#ifdef REALTIME
+  int priority;
+  struct sched_param schedp;
+#endif
+
+  p->state = COND_START;
+  p->start = 0;
+  p->stop = 0;
+
+  if (pthread_mutex_init (&p->mutex, NULL) != 0)
+    error (EXIT_FAILURE, errno, "pthread_mutex_init failed");
+
+  if (pthread_condattr_init (&cond_attr) != 0)
+    error (EXIT_FAILURE, errno, "pthread_condattr_init failed");
+
+  if (p->flags & TIMEDWAIT_FLAG)
+    if (pthread_condattr_setclock (&cond_attr, CLOCK_MONOTONIC) !
= 0)
+      error (EXIT_FAILURE, errno, "pthread_condattr_setclock failed");
+
+  if (pthread_cond_init (&p->cond, &cond_attr) != 0)
+    error (EXIT_FAILURE, errno, "pthread_cond_init failed");
+
+  if (pthread_attr_init (&attr) != 0)
+    error (EXIT_FAILURE, errno, "pthread_attr_init failed");
+
+#ifdef REALTIME
+  priority = sched_get_priority_max (SCHED_FIFO);
+  if (priority == -1)
+    error (EXIT_FAILURE, errno, "sched_get_priority_max failed");
+
+  schedp.sched_priority = priority - 1;
+  if (sched_setscheduler (getpid (), SCHED_FIFO, &schedp) != 0)
+    error (EXIT_FAILURE, errno, "sched_setscheduler failed");
+
+  if (pthread_attr_setschedpolicy (&attr, SCHED_FIFO) != 0)
+    error (EXIT_FAILURE, errno, "sched_setscheduler failed");
+
+  if (pthread_attr_setschedparam (&attr, &schedp) != 0)
+    error (EXIT_FAILURE, errno, "sched_setscheduler failed");
+#endif
+
+  if (pthread_create (&p->tid, &attr, function, (void *) p) != 0)
+    error (EXIT_FAILURE, errno, "pthread_create failed");
+}
+
+static void *
+signaler (void *arg)
+{
+  params_t *p = (params_t *) arg;
+  uint32_t i;
+
+  for (i = 0; i < p->iters; i++)
+    {
+      pthread_mutex_lock (&p->mutex);
+      if (p->flags & BROADCAST_FLAG)
+       {
+         TIMING_NOW (p->start);
+         if (pthread_cond_broadcast (&p->cond) != 0)
+           error (EXIT_FAILURE, errno, "pthread_cond_broadcast failed");
+       }
+      else
+       {
+         TIMING_NOW (p->start);
+         if (pthread_cond_signal (&p->cond) != 0)
+           error (EXIT_FAILURE, errno, "pthread_cond_signal failed");
+       }
+      TIMING_NOW (p->stop);
+      update_stats (p);
+      pthread_mutex_unlock (&p->mutex);
+    }
+
+  return NULL;
+}
+
+static void
+do_signal_test (size_t niters, size_t nthreads, uint32_t flags)
+{
+  uint32_t i;
+  params_t *params;
+
+  init_stats ();
+
+  params = (params_t *) malloc (sizeof (params_t) * nthreads);
+  if (params == NULL)
+    error (EXIT_FAILURE, errno, "out of memory");
+
+  for (i = 0; i < nthreads; i++)
+    {
+      params[i].iters = niters;
+      params[i].flags = flags;
+      create_thread (&params[i], signaler);
+    }
+
+  for (i = 0; i < nthreads; i++)
+    pthread_join (params[i].tid, NULL);
+
+  printf ("%s\t",
+         (flags & BROADCAST_FLAG) ?
+         "broadcast (w/o waiters)" : "signal (w/o waiters)");
+  print_stats (niters, nthreads);
+
+  free (params);
+}
+
+static void *
+waiter (void *arg)
+{
+  params_t *p = (params_t *) arg;
+  struct timespec ts;
+
+  while (p->state == COND_START)
+    {
+      pthread_mutex_lock (&p->mutex);
+      p->state = COND_WAITING;
+      if (p->flags & TIMEDWAIT_FLAG)
+       {
+         if (clock_gettime (CLOCK_MONOTONIC, &ts) != 0)
+           error (EXIT_FAILURE, errno, "clock_gettime failed");
+
+         /* Long timeout value, for this benchmark
+            we do not want to time out. */
+         ts.tv_sec += 60;
+         if (pthread_cond_timedwait (&p->cond, &p->mutex, &ts) != 0)
+           error (EXIT_FAILURE, errno, "pthread_cond_timedwait failed");
+       }
+      else
+       {
+         if (pthread_cond_wait (&p->cond, &p->mutex) != 0)
+           error (EXIT_FAILURE, errno, "pthread_cond_wait failed");
+       }
+      if (p->flags & ROUNDTRIP_FLAG)
+       {
+         TIMING_NOW (p->stop);
+         update_stats (p);
+       }
+      if (p->state == COND_STOP)
+       {
+         pthread_mutex_unlock (&p->mutex);
+         break;
+       }
+      p->state = COND_SIGNALED;
+      pthread_mutex_unlock (&p->mutex);
+
+      while (p->state == COND_SIGNALED)
+       sched_yield ();
+    }
+
+  return NULL;
+}
+
+static void
+signal_waiter (params_t *p)
+{
+  pthread_mutex_lock (&p->mutex);
+  while (p->state == COND_START)
+    {
+      pthread_mutex_unlock (&p->mutex);
+      sched_yield ();
+      pthread_mutex_lock (&p->mutex);
+    }
+
+  if (p->flags & BROADCAST_FLAG)
+    {
+      TIMING_NOW (p->start);
+      if (pthread_cond_broadcast (&p->cond) != 0)
+       error (EXIT_FAILURE, errno, "pthread_cond_broadcast failed");
+    }
+  else
+    {
+      TIMING_NOW (p->start);
+      if (pthread_cond_signal (&p->cond) != 0)
+       error (EXIT_FAILURE, errno, "pthread_cond_signal failed");
+    }
+  if (!(p->flags & ROUNDTRIP_FLAG))
+    {
+      TIMING_NOW (p->stop);
+      update_stats (p);
+    }
+
+  do
+    {
+      pthread_mutex_unlock (&p->mutex);
+      sched_yield ();
+      pthread_mutex_lock (&p->mutex);
+    }
+  while (p->state != COND_SIGNALED);
+
+  p->state = COND_START;
+  pthread_mutex_unlock (&p->mutex);
+}
+
+static void
+stop_waiter (params_t *p)
+{
+  pthread_mutex_lock (&p->mutex);
+  while (p->state != COND_WAITING)
+    {
+      pthread_mutex_unlock (&p->mutex);
+      sched_yield ();
+      pthread_mutex_lock (&p->mutex);
+    }
+  p->state = COND_STOP;
+  pthread_cond_signal (&p->cond);
+  pthread_mutex_unlock (&p->mutex);
+
+  pthread_join (p->tid, NULL);
+}
+
+static void
+do_test (size_t niters, size_t nthreads, uint32_t flags)
+{
+  size_t i, j;
+  params_t *params;
+
+  init_stats ();
+
+  params = (params_t *) malloc (sizeof (params_t) * nthreads);
+  if (params == NULL)
+    error (EXIT_FAILURE, errno, "out of memory");
+
+  for (i = 0; i < nthreads; i++)
+    {
+      params[i].flags = flags;
+      create_thread (&params[i], waiter);
+    }
+
+  for (i = 0; i < niters; i++)
+    for (j = 0; j < nthreads; j++)
+      signal_waiter (&params[j]);
+
+  for (i = 0; i < nthreads; i++)
+    stop_waiter (&params[i]);
+
+  if (flags & ROUNDTRIP_FLAG)
+    printf ("%s/%s\t",
+           (flags & BROADCAST_FLAG) ? "broadcast" : "signal",
+           (flags & TIMEDWAIT_FLAG) ? "timedwait" : "wait\t");
+  else
+    printf ("%s\t\t",
+           (flags & BROADCAST_FLAG) ? "broadcast" : "signal\t");
+  print_stats (niters, nthreads);
+
+  free (params);
+}
+
+int
+test_main (void)
+{
+  int ret;
+
+  printf ("pthread_cond_[test]\titerations    threads    mean       min  
"
+         "max         variance       std. deviation\n");
+  printf 
("-----------------------------------------------------------------"
+         "--------------------------------------------\n");
+  do_signal_test (1000000, 100, 0);
+  do_signal_test (1000000, 100, BROADCAST_FLAG);
+  do_test (1000000, 1, 0);
+  do_test (1000000, 1, BROADCAST_FLAG);
+  do_test (100000, 100, ROUNDTRIP_FLAG);
+  do_test (100000, 100, TIMEDWAIT_FLAG | ROUNDTRIP_FLAG);
+  do_test (100000, 100, BROADCAST_FLAG | ROUNDTRIP_FLAG);
+  do_test (100000, 100, BROADCAST_FLAG | TIMEDWAIT_FLAG | 
ROUNDTRIP_FLAG);
+
+  return EXIT_SUCCESS;
+}
+
+#define TIMEOUT (4 * 60)
+#define TEST_FUNCTION test_main ()
+#include "../test-skeleton.c"
-- 
1.8.5.2