benchtests/bench-memcmp.c

   1 /* Measure memcmp functions.
   2    Copyright (C) 2013-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #define TEST_MAIN
  20 #ifdef WIDE
  21 # define TEST_NAME "wmemcmp"
  22 #else
  23 # define TEST_NAME "memcmp"
  24 #endif
  25 #include "bench-string.h"
  26 #ifdef WIDE
  27 # include <inttypes.h>
  28 # include <wchar.h>
  29
  30 # define MEMCMP wmemcmp
  31 # define MEMCPY wmemcpy
  32 # define SIMPLE_MEMCMP simple_wmemcmp
  33 # define CHAR wchar_t
  34 # define UCHAR wchar_t
  35 # define CHARBYTES 4
  36 # define CHAR__MIN WCHAR_MIN
  37 # define CHAR__MAX WCHAR_MAX
  38 int
  39 simple_wmemcmp (const wchar_t *s1, const wchar_t *s2, size_t n)
  40 {
  41   int ret = 0;
  42   /* Warning!
  43         wmemcmp has to use SIGNED comparison for elements.
  44         memcmp has to use UNSIGNED comparison for elemnts.
  45   */
  46   while (n-- && (ret = *s1 < *s2 ? -1 : *s1 == *s2 ? 0 : 1) == 0) {s1++; s2++;}
  47   return ret;
  48 }
  49 #else
  50 # include <limits.h>
  51
  52 # define MEMCMP memcmp
  53 # define MEMCPY memcpy
  54 # define SIMPLE_MEMCMP simple_memcmp
  55 # define CHAR char
  56 # define MAX_CHAR 255
  57 # define UCHAR unsigned char
  58 # define CHARBYTES 1
  59 # define CHAR__MIN CHAR_MIN
  60 # define CHAR__MAX CHAR_MAX
  61
  62 int
  63 simple_memcmp (const char *s1, const char *s2, size_t n)
  64 {
  65   int ret = 0;
  66
  67   while (n-- && (ret = *(unsigned char *) s1++ - *(unsigned char *) s2++) == 0);
  68   return ret;
  69 }
  70 #endif
  71
  72 typedef int (*proto_t) (const CHAR *, const CHAR *, size_t);
  73
  74 IMPL (SIMPLE_MEMCMP, 0)
  75 IMPL (MEMCMP, 1)
  76
  77 static void
  78 do_one_test (impl_t *impl, const CHAR *s1, const CHAR *s2, size_t len,
  79              int exp_result)
  80 {
  81   size_t i, iters = INNER_LOOP_ITERS;
  82   timing_t start, stop, cur;
  83
  84   TIMING_NOW (start);
  85   for (i = 0; i < iters; ++i)
  86     {
  87       CALL (impl, s1, s2, len);
  88     }
  89   TIMING_NOW (stop);
  90
  91   TIMING_DIFF (cur, start, stop);
  92
  93   TIMING_PRINT_MEAN ((double) cur, (double) iters);
  94 }
  95
  96 static void
  97 do_test (size_t align1, size_t align2, size_t len, int exp_result)
  98 {
  99   size_t i;
 100   CHAR *s1, *s2;
 101
 102   if (len == 0)
 103     return;
 104
 105   align1 &= 63;
 106   if (align1 + (len + 1) * CHARBYTES >= page_size)
 107     return;
 108
 109   align2 &= 63;
 110   if (align2 + (len + 1) * CHARBYTES >= page_size)
 111     return;
 112
 113   s1 = (CHAR *) (buf1 + align1);
 114   s2 = (CHAR *) (buf2 + align2);
 115
 116   for (i = 0; i < len; i++)
 117     s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % CHAR__MAX;
 118
 119   s1[len] = align1;
 120   s2[len] = align2;
 121   s2[len - 1] -= exp_result;
 122
 123   printf ("Length %4zd, alignment %2zd/%2zd:", len, align1, align2);
 124
 125   FOR_EACH_IMPL (impl, 0)
 126     do_one_test (impl, s1, s2, len, exp_result);
 127
 128   putchar ('\n');
 129 }
 130
 131 int
 132 test_main (void)
 133 {
 134   size_t i;
 135
 136   test_init ();
 137
 138   printf ("%23s", "");
 139   FOR_EACH_IMPL (impl, 0)
 140     printf ("\t%s", impl->name);
 141   putchar ('\n');
 142
 143   for (i = 1; i < 16; ++i)
 144     {
 145       do_test (i * CHARBYTES, i * CHARBYTES, i, 0);
 146       do_test (i * CHARBYTES, i * CHARBYTES, i, 1);
 147       do_test (i * CHARBYTES, i * CHARBYTES, i, -1);
 148     }
 149
 150   for (i = 0; i < 16; ++i)
 151     {
 152       do_test (0, 0, i, 0);
 153       do_test (0, 0, i, 1);
 154       do_test (0, 0, i, -1);
 155     }
 156
 157   for (i = 1; i < 10; ++i)
 158     {
 159       do_test (0, 0, 2 << i, 0);
 160       do_test (0, 0, 2 << i, 1);
 161       do_test (0, 0, 2 << i, -1);
 162       do_test (0, 0, 16 << i, 0);
 163       do_test ((8 - i) * CHARBYTES, (2 * i) * CHARBYTES, 16 << i, 0);
 164       do_test (0, 0, 16 << i, 1);
 165       do_test (0, 0, 16 << i, -1);
 166     }
 167
 168   for (i = 1; i < 8; ++i)
 169     {
 170       do_test (i * CHARBYTES, 2 * (i * CHARBYTES), 8 << i, 0);
 171       do_test (i * CHARBYTES, 2 * (i * CHARBYTES), 8 << i, 1);
 172       do_test (i * CHARBYTES, 2 * (i * CHARBYTES), 8 << i, -1);
 173     }
 174
 175   return ret;
 176 }
 177
 178 #include <support/test-driver.c>