glibc/benchtests/bench-memcmp.c

/* Measure memcmp functions.
   Copyright (C) 2013-2017 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/>.  */

#define TEST_MAIN
#ifdef WIDE
# define TEST_NAME "wmemcmp"
#else
# define TEST_NAME "memcmp"
#endif
#include "bench-string.h"
#ifdef WIDE
# include <inttypes.h>
# include <wchar.h>

# define MEMCMP wmemcmp
# define MEMCPY wmemcpy
# define SIMPLE_MEMCMP simple_wmemcmp
# define CHAR wchar_t
# define UCHAR wchar_t
# define CHARBYTES 4
# define CHAR__MIN WCHAR_MIN
# define CHAR__MAX WCHAR_MAX
int
simple_wmemcmp (const wchar_t *s1, const wchar_t *s2, size_t n)
{
  int ret = 0;
  /* Warning!
	wmemcmp has to use SIGNED comparison for elements.
	memcmp has to use UNSIGNED comparison for elemnts.
  */
  while (n-- && (ret = *s1 < *s2 ? -1 : *s1 == *s2 ? 0 : 1) == 0) {s1++; s2++;}
  return ret;
}
#else
# include <limits.h>

# define MEMCMP memcmp
# define MEMCPY memcpy
# define SIMPLE_MEMCMP simple_memcmp
# define CHAR char
# define MAX_CHAR 255
# define UCHAR unsigned char
# define CHARBYTES 1
# define CHAR__MIN CHAR_MIN
# define CHAR__MAX CHAR_MAX

int
simple_memcmp (const char *s1, const char *s2, size_t n)
{
  int ret = 0;

  while (n-- && (ret = *(unsigned char *) s1++ - *(unsigned char *) s2++) == 0);
  return ret;
}
#endif

typedef int (*proto_t) (const CHAR *, const CHAR *, size_t);

IMPL (SIMPLE_MEMCMP, 0)
IMPL (MEMCMP, 1)

static void
do_one_test (impl_t *impl, const CHAR *s1, const CHAR *s2, size_t len,
	     int exp_result)
{
  size_t i, iters = INNER_LOOP_ITERS;
  timing_t start, stop, cur;

  TIMING_NOW (start);
  for (i = 0; i < iters; ++i)
    {
      CALL (impl, s1, s2, len);
    }
  TIMING_NOW (stop);

  TIMING_DIFF (cur, start, stop);

  TIMING_PRINT_MEAN ((double) cur, (double) iters);
}

static void
do_test (size_t align1, size_t align2, size_t len, int exp_result)
{
  size_t i;
  CHAR *s1, *s2;

  if (len == 0)
    return;

  align1 &= 63;
  if (align1 + (len + 1) * CHARBYTES >= page_size)
    return;

  align2 &= 63;
  if (align2 + (len + 1) * CHARBYTES >= page_size)
    return;

  s1 = (CHAR *) (buf1 + align1);
  s2 = (CHAR *) (buf2 + align2);

  for (i = 0; i < len; i++)
    s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % CHAR__MAX;

  s1[len] = align1;
  s2[len] = align2;
  s2[len - 1] -= exp_result;

  printf ("Length %4zd, alignment %2zd/%2zd:", len, align1, align2);

  FOR_EACH_IMPL (impl, 0)
    do_one_test (impl, s1, s2, len, exp_result);

  putchar ('\n');
}

int
test_main (void)
{
  size_t i;

  test_init ();

  printf ("%23s", "");
  FOR_EACH_IMPL (impl, 0)
    printf ("\t%s", impl->name);
  putchar ('\n');

  for (i = 1; i < 16; ++i)
    {
      do_test (i * CHARBYTES, i * CHARBYTES, i, 0);
      do_test (i * CHARBYTES, i * CHARBYTES, i, 1);
      do_test (i * CHARBYTES, i * CHARBYTES, i, -1);
    }

  for (i = 0; i < 16; ++i)
    {
      do_test (0, 0, i, 0);
      do_test (0, 0, i, 1);
      do_test (0, 0, i, -1);
    }

  for (i = 1; i < 10; ++i)
    {
      do_test (0, 0, 2 << i, 0);
      do_test (0, 0, 2 << i, 1);
      do_test (0, 0, 2 << i, -1);
      do_test (0, 0, 16 << i, 0);
      do_test ((8 - i) * CHARBYTES, (2 * i) * CHARBYTES, 16 << i, 0);
      do_test (0, 0, 16 << i, 1);
      do_test (0, 0, 16 << i, -1);
    }

  for (i = 1; i < 8; ++i)
    {
      do_test (i * CHARBYTES, 2 * (i * CHARBYTES), 8 << i, 0);
      do_test (i * CHARBYTES, 2 * (i * CHARBYTES), 8 << i, 1);
      do_test (i * CHARBYTES, 2 * (i * CHARBYTES), 8 << i, -1);
    }

  return ret;
}

#include <support/test-driver.c>