Re: [PATCH v2] benchtests: Add pthread-mutex-locks bench

[Noah Goldstein <goldstein.w.n@gmail.com>]

On Thu, Apr 21, 2022 at 5:58 PM Guo, Wangyang <wangyang.guo@intel.com> wrote:
>
> On 4/21/2022 9:13 PM, Noah Goldstein via Libc-alpha wrote:
> > On Wed, Apr 20, 2022 at 10:29 PM Wangyang Guo <wangyang.guo@intel.com> wrote:
> >>
> >> Benchmark for testing pthread mutex locks performance with different
> >> threads and critical sections.
> >>
> >> The test configuration consists of 3 parts:
> >> 1. thread number
> >> 2. critical-section length
> >> 3. non-critical-section length
> >>
> >> Thread number starts from 1 and increased by 2x until num of CPU cores
> >> (nprocs). An additional over-saturation case (1.25 * nprocs) is also
> >> included.
> >> Critical-section is represented by a loop of shared do_filler(),
> >> length can be determined by the loop iters.
> >> Non-critical-section is similiar to the critical-section, except it's
> >> based on non-shared do_filler().
> >>
> >> Currently, adaptive pthread_mutex lock is tested.
> >>
> >> v2: Fix benchout json schema validation error.
> >> ---
> >>   benchtests/Makefile                    |   2 +
> >>   benchtests/bench-pthread-mutex-locks.c | 288 +++++++++++++++++++++++++
> >>   2 files changed, 290 insertions(+)
> >>   create mode 100644 benchtests/bench-pthread-mutex-locks.c
> >>
> >> diff --git a/benchtests/Makefile b/benchtests/Makefile
> >> index 8dfca592fd..b477042e6c 100644
> >> --- a/benchtests/Makefile
> >> +++ b/benchtests/Makefile
> >> @@ -102,6 +102,7 @@ endif
> >>
> >>   bench-pthread := \
> >>     pthread-locks \
> >> +  pthread-mutex-locks \
> >>     pthread_once \
> >>     thread_create \
> >>   # bench-pthread
> >> @@ -281,6 +282,7 @@ $(addprefix $(objpfx)bench-,$(math-benchset)): $(libm-benchtests)
> >>   $(addprefix $(objpfx)bench-,$(bench-pthread)): $(thread-library-benchtests)
> >>   $(addprefix $(objpfx)bench-,$(bench-malloc)): $(thread-library-benchtests)
> >>   $(addprefix $(objpfx)bench-,pthread-locks): $(libm-benchtests)
> >> +$(addprefix $(objpfx)bench-,pthread-mutex-locks): $(libm-benchtests)
> >>
> >>
> >>
> >> diff --git a/benchtests/bench-pthread-mutex-locks.c b/benchtests/bench-pthread-mutex-locks.c
> >> new file mode 100644
> >> index 0000000000..e934b0001a
> >> --- /dev/null
> >> +++ b/benchtests/bench-pthread-mutex-locks.c
> >> @@ -0,0 +1,288 @@
> >> +/* Measure mutex_lock for different threads and critical sections.
> >> +   Copyright (C) 2020-2022 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
> >> +   <https://www.gnu.org/licenses/>.  */
> >> +
> >> +#define TEST_MAIN
> >> +#define TEST_NAME "pthread-mutex-locks"
> >> +#define TIMEOUT (20 * 60)
> >> +
> >> +#include <stdio.h>
> >> +#include <stdlib.h>
> >> +#include <string.h>
> >> +#include <unistd.h>
> >> +#include <math.h>
> >> +#include <pthread.h>
> >> +#include <sys/time.h>
> >> +#include <sys/sysinfo.h>
> >> +#include "bench-timing.h"
> >> +#include "json-lib.h"
> >> +
> >> +static pthread_mutex_t lock;
> >> +static pthread_mutexattr_t attr;
> >> +static pthread_barrier_t barrier;
> >> +
> >> +#define START_ITERS 1000
> >> +
> >> +#pragma GCC push_options
> >> +#pragma GCC optimize(1)
> >> +
> >> +static int __attribute__ ((noinline)) fibonacci (int i)
> >> +{
> >> +  asm("");
> >> +  if (i > 2)
> >> +    return fibonacci (i - 1) + fibonacci (i - 2);
> >> +  return 10 + i;
> >> +}
> >> +
> >> +static void
> >> +do_filler (void)
> >> +{
> >> +  char buf1[512], buf2[512];
> >> +  int f = fibonacci (4);
> >> +  memcpy (buf1, buf2, f);
> >> +}
> >> +
> >> +static void
> >> +do_filler_shared (void)
> >> +{
> >> +  static char buf1[512], buf2[512];
> >> +  int f = fibonacci (4);
> >> +  memcpy (buf1, buf2, f);
> >> +}
> >> +
> >> +#pragma GCC pop_options
> >> +
> >> +#define UNIT_WORK_CRT do_filler_shared ()
> >> +#define UNIT_WORK_NON_CRT do_filler ()
> >> +
> >> +static inline void
> >> +critical_section (int length)
> >> +{
> >> +  for (int i = length; i >= 0; i--)
> >> +    UNIT_WORK_CRT;
> >> +}
> >> +
> >> +static inline void
> >> +non_critical_section (int length)
> >> +{
> >> +  for (int i = length; i >= 0; i--)
> >> +    UNIT_WORK_NON_CRT;
> >> +}
> >> +
> >> +typedef struct Worker_Params
> >> +{
> >> +  long iters;
> >> +  int crt_len;
> >> +  int non_crt_len;
> >> +  timing_t duration;
> >> +} Worker_Params;
> >> +
> >> +static void *
> >> +worker (void *v)
> >> +{
> >> +  timing_t start, stop;
> >> +  Worker_Params *p = (Worker_Params *) v;
> >> +  long iters = p->iters;
> >> +  int crt_len = p->crt_len;
> >> +  int non_crt_len = p->non_crt_len;
> >> +
> >> +  pthread_barrier_wait (&barrier);
> >> +  TIMING_NOW (start);
> >> +  while (iters--)
> >> +    {
> >> +      pthread_mutex_lock (&lock);
> >> +      critical_section (crt_len);
> >> +      pthread_mutex_unlock (&lock);
> >> +      non_critical_section (non_crt_len);
> >> +    }
> >> +  TIMING_NOW (stop);
> >> +
> >> +  TIMING_DIFF (p->duration, start, stop);
> >> +  return NULL;
> >> +}
> >> +
> >> +static double
> >> +do_one_test (int num_threads, int crt_len, int non_crt_len, long iters)
> >> +{
> >> +  int i;
> >> +  timing_t mean;
> >> +  Worker_Params *p, params[num_threads];
> >> +  pthread_t threads[num_threads];
> >> +
> >> +  pthread_mutex_init (&lock, &attr);
> >> +  pthread_barrier_init (&barrier, NULL, num_threads);
> >> +
> >> +  for (i = 0; i < num_threads; i++)
> >> +    {
> >> +      p = &params[i];
> >> +      p->iters = iters;
> >> +      p->crt_len = crt_len;
> >> +      p->non_crt_len = non_crt_len;
> >> +      pthread_create (&threads[i], NULL, worker, (void *) p);
> >> +    }
> >> +  for (i = 0; i < num_threads; i++)
> >> +    pthread_join (threads[i], NULL);
> >> +
> >> +  pthread_mutex_destroy (&lock);
> >> +  pthread_barrier_destroy (&barrier);
> >> +
> >> +  mean = 0;
> >> +  for (i = 0; i < num_threads; i++)
> >> +    mean += params[i].duration;
> >> +  mean /= num_threads;
> >> +  return mean;
> >> +}
> >> +
> >> +#define RUN_COUNT 10
> >> +#define MIN_TEST_SEC 0.01
> >> +
> >> +static void
> >> +do_bench_one (const char *name, int num_threads, int crt_len, int non_crt_len,
> >> +             json_ctx_t *js)
> >> +{
> >> +  timing_t cur;
> >> +  struct timeval ts, te;
> >> +  double tsd, ted, td;
> >> +  long iters, iters_limit, total_iters;
> >> +  timing_t curs[RUN_COUNT + 2];
> >> +  int i, j;
> >> +  double mean, stdev;
> >> +
> >> +  iters = START_ITERS;
> >> +  iters_limit = LONG_MAX / 100;
> >> +
> >> +  while (1)
> >> +    {
> >> +      gettimeofday (&ts, NULL);
> >> +      cur = do_one_test (num_threads, crt_len, non_crt_len, iters);
> >> +      gettimeofday (&te, NULL);
> >> +      /* Make sure the test to run at least MIN_TEST_SEC.  */
> >> +      tsd = ts.tv_sec + ts.tv_usec / 1000000.0;
> >> +      ted = te.tv_sec + te.tv_usec / 1000000.0;
> >> +      td = ted - tsd;
> >> +      if (td >= MIN_TEST_SEC || iters >= iters_limit)
> >> +       break;
> >> +
> >> +      iters *= 10;
> >> +    }
> >> +
> >> +  curs[0] = cur;
> >> +  for (i = 1; i < RUN_COUNT + 2; i++)
> >> +    curs[i] = do_one_test (num_threads, crt_len, non_crt_len, iters);
> >> +
> >> +  /* Sort the results so we can discard the fastest and slowest
> >> +     times as outliers.  */
> >> +  for (i = 0; i < RUN_COUNT + 1; i++)
> >> +    for (j = i + 1; j < RUN_COUNT + 2; j++)
> >> +      if (curs[i] > curs[j])
> >> +       {
> >> +         timing_t temp = curs[i];
> >> +         curs[i] = curs[j];
> >> +         curs[j] = temp;
> >> +       }
> >> +
> >> +  /* Calculate mean and standard deviation.  */
> >> +  mean = 0.0;
> >> +  total_iters = iters * num_threads;
> >> +  for (i = 1; i < RUN_COUNT + 1; i++)
> >> +    mean += (double) curs[i] / (double) total_iters;
> >> +  mean /= RUN_COUNT;
> >> +
> >> +  stdev = 0.0;
> >> +  for (i = 1; i < RUN_COUNT + 1; i++)
> >> +    {
> >> +      double s = (double) curs[i] / (double) total_iters - mean;
> >> +      stdev += s * s;
> >> +    }
> >> +  stdev = sqrt (stdev / (RUN_COUNT - 1));
> >> +
> >> +  char buf[256];
> >> +  snprintf (buf, sizeof buf, "%s,non_crt_len=%d,crt_len=%d,threads=%d", name,
> >> +           non_crt_len, crt_len, num_threads);
> >> +
> >> +  json_attr_object_begin (js, buf);
> >> +
> >> +  json_attr_double (js, "duration", (double) cur);
> >> +  json_attr_double (js, "iterations", (double) total_iters);
> >> +  json_attr_double (js, "mean", mean);
> >> +  json_attr_double (js, "stdev", stdev);
> >> +  json_attr_double (js, "min-outlier",
> >> +                   (double) curs[0] / (double) total_iters);
> >> +  json_attr_double (js, "min", (double) curs[1] / (double) total_iters);
> >> +  json_attr_double (js, "max",
> >> +                   (double) curs[RUN_COUNT] / (double) total_iters);
> >> +  json_attr_double (js, "max-outlier",
> >> +                   (double) curs[RUN_COUNT + 1] / (double) total_iters);
> >> +
> >> +  json_attr_object_end (js);
> >> +}
> >> +
> >> +#define TH_CONF_MAX 10
> >> +
> >> +int
> >> +do_bench (void)
> >> +{
> >> +  int rv = 0;
> >> +  json_ctx_t json_ctx;
> >> +  int i, j, k;
> >> +  int th_num, th_conf, nprocs;
> >> +  int threads[TH_CONF_MAX];
> >> +  int crt_lens[] = { 0, 1, 2, 4, 8, 16, 32, 64, 128 };
> >> +  int non_crt_lens[] = { 1, 32, 128 };
> >> +  char name[128];
> >> +
> >> +  json_init (&json_ctx, 2, stdout);
> >> +  json_attr_object_begin (&json_ctx, "pthread_mutex_locks");
> >> +
> >> +  /* The thread config begins from 1, and increases by 2x until nprocs.
> >> +     We also wants to test over-saturation case (1.25*nprocs).  */
> >> +  nprocs = get_nprocs ();
> >> +  th_num = 1;
> >> +  for (th_conf = 0; th_conf < (TH_CONF_MAX - 2) && th_num < nprocs; th_conf++)
> >> +    {
> >> +      threads[th_conf] = th_num;
> >> +      th_num <<= 1;
> >> +    }
> >> +  threads[th_conf++] = nprocs;
> >> +  threads[th_conf++] = nprocs + nprocs / 4;
> >> +
> >> +  pthread_mutexattr_init (&attr);
> >> +  pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
> >> +  snprintf (name, sizeof name, "type=adaptive");
> >> +
> >> +  for (k = 0; k < (sizeof (non_crt_lens) / sizeof (int)); k++)
> >> +    {
> >> +      int non_crt_len = non_crt_lens[k];
> >> +      for (j = 0; j < (sizeof (crt_lens) / sizeof (int)); j++)
> >> +       {
> >> +         int crt_len = crt_lens[j];
> >> +         for (i = 0; i < th_conf; i++)
> >> +           {
> >> +             th_num = threads[i];
> >> +             do_bench_one (name, th_num, crt_len, non_crt_len, &json_ctx);
> >> +           }
> >> +       }
> >> +    }
> >> +
> >> +  json_attr_object_end (&json_ctx);
> >> +
> >> +  return rv;
> >> +}
> >> +
> >> +#define TEST_FUNCTION do_bench ()
> >> +
> >> +#include "../test-skeleton.c"
> >> --
> >> 2.35.1
> >>
> >
> > Can you run clang-format on this? Otherwise
> > LGTM.
> >
>
> clang-format done.
> Nothing needs to change for this patch.


Woops.

LGTM.