benchtests/bench-strcmp.c

   1 /* Measure strcmp and wcscmp 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 "wcscmp"
  22 #else
  23 # define TEST_NAME "strcmp"
  24 #endif
  25 #include "bench-string.h"
  26
  27 #ifdef WIDE
  28 # include <wchar.h>
  29
  30 # define L(str) L##str
  31 # define STRCMP wcscmp
  32 # define STRCPY wcscpy
  33 # define STRLEN wcslen
  34 # define MEMCPY wmemcpy
  35 # define SIMPLE_STRCMP simple_wcscmp
  36 # define STUPID_STRCMP stupid_wcscmp
  37 # define CHAR wchar_t
  38 # define UCHAR wchar_t
  39 # define CHARBYTES 4
  40 # define CHARBYTESLOG 2
  41 # define CHARALIGN __alignof__ (CHAR)
  42 # define MIDCHAR 0x7fffffff
  43 # define LARGECHAR 0xfffffffe
  44 # define CHAR__MAX WCHAR_MAX
  45 # define CHAR__MIN WCHAR_MIN
  46
  47 /* Wcscmp uses signed semantics for comparison, not unsigned */
  48 /* Avoid using substraction since possible overflow */
  49
  50 int
  51 simple_wcscmp (const wchar_t *s1, const wchar_t *s2)
  52 {
  53   wchar_t c1, c2;
  54   do
  55     {
  56       c1 = *s1++;
  57       c2 = *s2++;
  58       if (c2 == L'\0')
  59       return c1 - c2;
  60     }
  61   while (c1 == c2);
  62
  63   return c1 < c2 ? -1 : 1;
  64 }
  65
  66 int
  67 stupid_wcscmp (const wchar_t *s1, const wchar_t *s2)
  68 {
  69   size_t ns1 = wcslen (s1) + 1;
  70   size_t ns2 = wcslen (s2) + 1;
  71   size_t n = ns1 < ns2 ? ns1 : ns2;
  72   int ret = 0;
  73
  74   wchar_t c1, c2;
  75
  76   while (n--) {
  77     c1 = *s1++;
  78     c2 = *s2++;
  79     if ((ret = c1 < c2 ? -1 : c1 == c2 ? 0 : 1) != 0)
  80       break;
  81   }
  82   return ret;
  83 }
  84
  85 #else
  86 # include <limits.h>
  87
  88 # define L(str) str
  89 # define STRCMP strcmp
  90 # define STRCPY strcpy
  91 # define STRLEN strlen
  92 # define MEMCPY memcpy
  93 # define SIMPLE_STRCMP simple_strcmp
  94 # define STUPID_STRCMP stupid_strcmp
  95 # define CHAR char
  96 # define UCHAR unsigned char
  97 # define CHARBYTES 1
  98 # define CHARBYTESLOG 0
  99 # define CHARALIGN 1
 100 # define MIDCHAR 0x7f
 101 # define LARGECHAR 0xfe
 102 # define CHAR__MAX CHAR_MAX
 103 # define CHAR__MIN CHAR_MIN
 104
 105 /* Strcmp uses unsigned semantics for comparison. */
 106 int
 107 simple_strcmp (const char *s1, const char *s2)
 108 {
 109   int ret;
 110
 111   while ((ret = *(unsigned char *) s1 - *(unsigned char*) s2++) == 0 && *s1++);
 112   return ret;
 113 }
 114
 115 int
 116 stupid_strcmp (const char *s1, const char *s2)
 117 {
 118   size_t ns1 = strlen (s1) + 1;
 119   size_t ns2 = strlen (s2) + 1;
 120   size_t n = ns1 < ns2 ? ns1 : ns2;
 121   int ret = 0;
 122
 123   while (n--)
 124     if ((ret = *(unsigned char *) s1++ - *(unsigned char *) s2++) != 0)
 125       break;
 126   return ret;
 127 }
 128 #endif
 129
 130 typedef int (*proto_t) (const CHAR *, const CHAR *);
 131
 132 IMPL (STUPID_STRCMP, 1)
 133 IMPL (SIMPLE_STRCMP, 1)
 134 IMPL (STRCMP, 1)
 135
 136 static void
 137 do_one_test (impl_t *impl,
 138              const CHAR *s1, const CHAR *s2,
 139              int exp_result)
 140 {
 141   size_t i, iters = INNER_LOOP_ITERS;
 142   timing_t start, stop, cur;
 143
 144   TIMING_NOW (start);
 145   for (i = 0; i < iters; ++i)
 146     {
 147       CALL (impl, s1, s2);
 148     }
 149   TIMING_NOW (stop);
 150
 151   TIMING_DIFF (cur, start, stop);
 152
 153   TIMING_PRINT_MEAN ((double) cur, (double) iters);
 154 }
 155
 156 static void
 157 do_test (size_t align1, size_t align2, size_t len, int max_char,
 158          int exp_result)
 159 {
 160   size_t i;
 161
 162   CHAR *s1, *s2;
 163
 164   if (len == 0)
 165     return;
 166
 167   align1 &= 63;
 168   if (align1 + (len + 1) * CHARBYTES >= page_size)
 169     return;
 170
 171   align2 &= 63;
 172   if (align2 + (len + 1) * CHARBYTES >= page_size)
 173     return;
 174
 175   /* Put them close to the end of page.  */
 176   i = align1 + CHARBYTES * (len + 2);
 177   s1 = (CHAR *) (buf1 + ((page_size - i) / 16 * 16) + align1);
 178   i = align2 + CHARBYTES * (len + 2);
 179   s2 = (CHAR *) (buf2 + ((page_size - i) / 16 * 16)  + align2);
 180
 181   for (i = 0; i < len; i++)
 182     s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % max_char;
 183
 184   s1[len] = s2[len] = 0;
 185   s1[len + 1] = 23;
 186   s2[len + 1] = 24 + exp_result;
 187   s2[len - 1] -= exp_result;
 188
 189   printf ("Length %4zd, alignment %2zd/%2zd:", len, align1, align2);
 190
 191   FOR_EACH_IMPL (impl, 0)
 192     do_one_test (impl, s1, s2, exp_result);
 193
 194   putchar ('\n');
 195 }
 196
 197 int
 198 test_main (void)
 199 {
 200   size_t i;
 201
 202   test_init ();
 203
 204   printf ("%23s", "");
 205   FOR_EACH_IMPL (impl, 0)
 206     printf ("\t%s", impl->name);
 207   putchar ('\n');
 208
 209   for (i = 1; i < 32; ++i)
 210     {
 211       do_test (CHARBYTES * i, CHARBYTES * i, i, MIDCHAR, 0);
 212       do_test (CHARBYTES * i, CHARBYTES * i, i, MIDCHAR, 1);
 213       do_test (CHARBYTES * i, CHARBYTES * i, i, MIDCHAR, -1);
 214     }
 215
 216   for (i = 1; i < 10 + CHARBYTESLOG; ++i)
 217     {
 218       do_test (0, 0, 2 << i, MIDCHAR, 0);
 219       do_test (0, 0, 2 << i, LARGECHAR, 0);
 220       do_test (0, 0, 2 << i, MIDCHAR, 1);
 221       do_test (0, 0, 2 << i, LARGECHAR, 1);
 222       do_test (0, 0, 2 << i, MIDCHAR, -1);
 223       do_test (0, 0, 2 << i, LARGECHAR, -1);
 224       do_test (0, CHARBYTES * i, 2 << i, MIDCHAR, 1);
 225       do_test (CHARBYTES * i, CHARBYTES * (i + 1), 2 << i, LARGECHAR, 1);
 226     }
 227
 228   for (i = 1; i < 8; ++i)
 229     {
 230       do_test (CHARBYTES * i, 2 * CHARBYTES * i, 8 << i, MIDCHAR, 0);
 231       do_test (2 * CHARBYTES * i, CHARBYTES * i, 8 << i, LARGECHAR, 0);
 232       do_test (CHARBYTES * i, 2 * CHARBYTES * i, 8 << i, MIDCHAR, 1);
 233       do_test (2 * CHARBYTES * i, CHARBYTES * i, 8 << i, LARGECHAR, 1);
 234       do_test (CHARBYTES * i, 2 * CHARBYTES * i, 8 << i, MIDCHAR, -1);
 235       do_test (2 * CHARBYTES * i, CHARBYTES * i, 8 << i, LARGECHAR, -1);
 236     }
 237
 238   return ret;
 239 }
 240
 241 #include <support/test-driver.c>