Re: [PATCH 1/3] benchtests: Add malloc microbenchmark

[Siddhesh Poyarekar <siddhesh at redhat dot com>]

On Fri, Oct 03, 2014 at 04:11:24PM +0100, Will Newton wrote:
> Add a microbenchmark for measuring malloc and free performance. The
> benchmark allocates and frees buffers of random sizes in a random order
> and measures the overall execution time and RSS.
> 
> The random block sizes used follow an inverse square distribution
> which is intended to mimic the behaviour of real applications which
> tend to allocate many more small blocks than large ones.
> 
> ChangeLog:
> 
> 2014-10-03  Will Newton  <will.newton@linaro.org>
> 
> 	* benchtests/Makefile (stdlib-bench): Add malloc benchmark.
> 	* benchtests/bench-malloc.c: New file.

Looks OK to me with one minor nit (pointed out below) fixed.

> ---
>  benchtests/Makefile       |   2 +-
>  benchtests/bench-malloc.c | 219 ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 220 insertions(+), 1 deletion(-)
>  create mode 100644 benchtests/bench-malloc.c
> 
> diff --git a/benchtests/Makefile b/benchtests/Makefile
> index fd3036d..1f8eb82 100644
> --- a/benchtests/Makefile
> +++ b/benchtests/Makefile
> @@ -37,7 +37,7 @@ string-bench := bcopy bzero memccpy memchr memcmp memcpy memmem memmove \
>  		strspn strstr strcpy_chk stpcpy_chk memrchr strsep strtok
>  string-bench-all := $(string-bench)
>  
> -stdlib-bench := strtod
> +stdlib-bench := strtod malloc
>  
>  benchset := $(string-bench-all) $(stdlib-bench)
>  
> diff --git a/benchtests/bench-malloc.c b/benchtests/bench-malloc.c
> new file mode 100644
> index 0000000..54631ed
> --- /dev/null
> +++ b/benchtests/bench-malloc.c
> @@ -0,0 +1,219 @@
> +/* Benchmark malloc and free 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 <errno.h>
> +#include <math.h>
> +#include <signal.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/time.h>
> +#include <sys/resource.h>
> +#include <unistd.h>
> +
> +#include "bench-timing.h"
> +#include "json-lib.h"
> +
> +/* Benchmark duration in seconds.  */
> +#define BENCHMARK_DURATION	60
> +#define RAND_SEED		88
> +
> +/* Maximum memory that can be allocated at any one time is:
> +
> +   WORKING_SET_SIZE * MAX_ALLOCATION_SIZE
> +
> +   However due to the distribution of the random block sizes
> +   the typical amount allocated will be much smaller.  */
> +#define WORKING_SET_SIZE	1024
> +
> +#define MIN_ALLOCATION_SIZE	4
> +#define MAX_ALLOCATION_SIZE	32768
> +
> +/* Get a random block size with an inverse square distribution.  */
> +static unsigned int
> +get_block_size (unsigned int rand_data)
> +{
> +  /* Inverse square.  */
> +  const float exponent = -2;
> +  /* Minimum value of distribution.  */
> +  const float dist_min = MIN_ALLOCATION_SIZE;
> +  /* Maximum value of distribution.  */
> +  const float dist_max = MAX_ALLOCATION_SIZE;
> +
> +  float min_pow = powf (dist_min, exponent + 1);
> +  float max_pow = powf (dist_max, exponent + 1);
> +
> +  float r = (float) rand_data / RAND_MAX;
> +
> +  return (unsigned int) powf ((max_pow - min_pow) * r + min_pow, 1 / (exponent + 1));
> +}
> +
> +#define NUM_BLOCK_SIZES	8000
> +#define NUM_OFFSETS	((WORKING_SET_SIZE) * 4)
> +
> +static unsigned int random_block_sizes[NUM_BLOCK_SIZES];
> +static unsigned int random_offsets[NUM_OFFSETS];
> +
> +static void
> +init_random_values (void)
> +{
> +  for (size_t i = 0; i < NUM_BLOCK_SIZES; i++)
> +    random_block_sizes[i] = get_block_size (rand ());
> +
> +  for (size_t i = 0; i < NUM_OFFSETS; i++)
> +    random_offsets[i] = rand () % WORKING_SET_SIZE;
> +}
> +
> +static unsigned int
> +get_random_block_size (unsigned int *state)
> +{
> +  unsigned int idx = *state;
> +
> +  if (idx >= NUM_BLOCK_SIZES - 1)
> +    idx = 0;
> +  else
> +    idx++;
> +
> +  *state = idx;
> +
> +  return random_block_sizes[idx];
> +}
> +
> +static unsigned int
> +get_random_offset (unsigned int *state)
> +{
> +  unsigned int idx = *state;
> +
> +  if (idx >= NUM_OFFSETS - 1)
> +    idx = 0;
> +  else
> +    idx++;
> +
> +  *state = idx;
> +
> +  return random_offsets[idx];
> +}
> +
> +static volatile bool timeout;
> +
> +static void alarm_handler (int signum)

Line break after void.

> +{
> +  timeout = true;
> +}
> +
> +/* Allocate and free blocks in a random order.  */
> +static size_t
> +malloc_benchmark_loop (void **ptr_arr)
> +{
> +  unsigned int offset_state = 0, block_state = 0;
> +  size_t iters = 0;
> +
> +  while (!timeout)
> +    {
> +      unsigned int next_idx = get_random_offset (&offset_state);
> +      unsigned int next_block = get_random_block_size (&block_state);
> +
> +      free (ptr_arr[next_idx]);
> +
> +      ptr_arr[next_idx] = malloc (next_block);
> +
> +      iters++;
> +    }
> +
> +  return iters;
> +}
> +
> +static timing_t
> +do_benchmark (size_t *iters)
> +{
> +  timing_t elapsed, start, stop;
> +  void *working_set[WORKING_SET_SIZE];
> +
> +  memset (working_set, 0, sizeof (working_set));
> +
> +  TIMING_NOW (start);
> +  *iters = malloc_benchmark_loop (working_set);
> +  TIMING_NOW (stop);
> +
> +  TIMING_DIFF (elapsed, start, stop);
> +
> +  return elapsed;
> +}
> +
> +int
> +main (int argc, char **argv)
> +{
> +  timing_t cur;
> +  size_t iters = 0;
> +  unsigned long res;
> +  json_ctx_t json_ctx;
> +  double d_total_s, d_total_i;
> +  struct sigaction act;
> +
> +  init_random_values ();
> +
> +  json_init (&json_ctx, 0, stdout);
> +
> +  json_document_begin (&json_ctx);
> +
> +  json_attr_string (&json_ctx, "timing_type", TIMING_TYPE);
> +
> +  json_attr_object_begin (&json_ctx, "functions");
> +
> +  json_attr_object_begin (&json_ctx, "malloc");
> +
> +  json_attr_object_begin (&json_ctx, "");
> +
> +  TIMING_INIT (res);
> +
> +  (void) res;
> +
> +  memset (&act, 0, sizeof (act));
> +  act.sa_handler = &alarm_handler;
> +
> +  sigaction (SIGALRM, &act, NULL);
> +
> +  alarm (BENCHMARK_DURATION);
> +
> +  cur = do_benchmark (&iters);
> +
> +  struct rusage usage;
> +  getrusage(RUSAGE_SELF, &usage);
> +
> +  d_total_s = cur;
> +  d_total_i = iters;
> +
> +  json_attr_double (&json_ctx, "duration", d_total_s);
> +  json_attr_double (&json_ctx, "iterations", d_total_i);
> +  json_attr_double (&json_ctx, "time_per_iteration", d_total_s / d_total_i);
> +  json_attr_double (&json_ctx, "max_rss", usage.ru_maxrss);
> +
> +  json_attr_double (&json_ctx, "min_size", MIN_ALLOCATION_SIZE);
> +  json_attr_double (&json_ctx, "max_size", MAX_ALLOCATION_SIZE);
> +  json_attr_double (&json_ctx, "random_seed", RAND_SEED);
> +
> +  json_attr_object_end (&json_ctx);
> +
> +  json_attr_object_end (&json_ctx);
> +
> +  json_attr_object_end (&json_ctx);
> +
> +  json_document_end (&json_ctx);
> +
> +  return 0;
> +}
> -- 
> 1.9.3
>

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