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

[Will Newton <will dot newton at linaro dot org>]

On 7 July 2014 21:23, Gratian Crisan <gratian.crisan@ni.com> wrote:
> 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

This patch (and the others in the series) appear to me to be line
wrapped. Is it possible to use git-send-email to send the patches?

As it stands I cannot apply the patch to test it.

> 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

Is this required or a debugging leftover?

>  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));

memset is generally preferred to bzero.

> +}
> +
> +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;

Spaces around / please.

> +
> +  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;

iters is size_t so i should be too.

> +
> +  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;

Again size_t seems preferable.

> +  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;

Unused?

> +
> +  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
>



-- 
Will Newton
Toolchain Working Group, Linaro