benchtests/bench-memmem.c

   1 /* Measure memmem functions.
   2    Copyright (C) 2013-2024 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #define TEST_MAIN
  20 #define TEST_NAME "memmem"
  21 #define BUF1PAGES 20
  22 #define ITERATIONS 100
  23 #include "bench-string.h"
  24 #include "json-lib.h"
  25
  26 typedef char *(*proto_t) (const void *, size_t, const void *, size_t);
  27
  28 void *
  29 basic_memmem (const void *haystack, size_t hs_len, const void *needle,
  30               size_t ne_len)
  31 {
  32   const char *hs = haystack;
  33   const char *ne = needle;
  34
  35   if (ne_len == 0)
  36     return (void *)hs;
  37   int i;
  38   int c = ne[0];
  39   const char *end = hs + hs_len - ne_len;
  40
  41   for ( ; hs <= end; hs++)
  42   {
  43     if (hs[0] != c)
  44       continue;
  45     for (i = ne_len - 1; i != 0; i--)
  46       if (hs[i] != ne[i])
  47         break;
  48     if (i == 0)
  49       return (void *)hs;
  50   }
  51
  52   return NULL;
  53 }
  54
  55 #define RETURN_TYPE void *
  56 #define AVAILABLE(h, h_l, j, n_l) ((j) <= (h_l) - (n_l))
  57 #define FASTSEARCH(S,C,N) (void*) memchr ((void *)(S), (C), (N))
  58 #include "../string/str-two-way.h"
  59
  60 void *
  61 twoway_memmem (const void *haystack_start, size_t haystack_len,
  62                const void *needle_start, size_t needle_len)
  63 {
  64   /* Abstract memory is considered to be an array of 'unsigned char' values,
  65      not an array of 'char' values.  See ISO C 99 section 6.2.6.1.  */
  66   const unsigned char *haystack = (const unsigned char *) haystack_start;
  67   const unsigned char *needle = (const unsigned char *) needle_start;
  68
  69   if (needle_len == 0)
  70     /* The first occurrence of the empty string is deemed to occur at
  71        the beginning of the string.  */
  72     return (void *) haystack;
  73
  74   /* Sanity check, otherwise the loop might search through the whole
  75      memory.  */
  76   if (__glibc_unlikely (haystack_len < needle_len))
  77     return NULL;
  78
  79   /* Use optimizations in memchr when possible, to reduce the search
  80      size of haystack using a linear algorithm with a smaller
  81      coefficient.  However, avoid memchr for long needles, since we
  82      can often achieve sublinear performance.  */
  83   if (needle_len < LONG_NEEDLE_THRESHOLD)
  84     {
  85       haystack = memchr (haystack, *needle, haystack_len);
  86       if (!haystack || __builtin_expect (needle_len == 1, 0))
  87         return (void *) haystack;
  88       haystack_len -= haystack - (const unsigned char *) haystack_start;
  89       if (haystack_len < needle_len)
  90         return NULL;
  91       /* Check whether we have a match.  This improves performance since we
  92          avoid the initialization overhead of the two-way algorithm.  */
  93       if (memcmp (haystack, needle, needle_len) == 0)
  94         return (void *) haystack;
  95       return two_way_short_needle (haystack, haystack_len, needle, needle_len);
  96     }
  97   else
  98     return two_way_long_needle (haystack, haystack_len, needle, needle_len);
  99 }
 100
 101 IMPL (memmem, 1)
 102 IMPL (twoway_memmem, 0)
 103 IMPL (basic_memmem, 0)
 104
 105 static void
 106 do_one_test (json_ctx_t *json_ctx, impl_t *impl, const void *haystack,
 107              size_t haystack_len, const void *needle, size_t needle_len,
 108              const void *expected)
 109 {
 110   size_t i, iters = INNER_LOOP_ITERS_SMALL;
 111   timing_t start, stop, cur;
 112   void *res;
 113   TIMING_NOW (start);
 114   for (i = 0; i < iters; ++i)
 115     {
 116       res = CALL (impl, haystack, haystack_len, needle, needle_len);
 117     }
 118   TIMING_NOW (stop);
 119
 120   TIMING_DIFF (cur, start, stop);
 121
 122   json_element_double (json_ctx, (double) cur / (double) iters);
 123
 124   if (res != expected)
 125     {
 126       error (0, 0, "Wrong result in function (%p != %p) %s(%p, %zu, %p, %zu)",
 127              res, expected, impl->name, haystack, haystack_len, needle,
 128              needle_len);
 129       ret = 1;
 130     }
 131 }
 132
 133 static void
 134 do_test (json_ctx_t *json_ctx, const char *str, size_t len, size_t idx)
 135 {
 136   char tmpbuf[len];
 137
 138   memcpy (tmpbuf, buf1 + idx, len);
 139   memcpy (buf1 + idx, str, len);
 140
 141   json_element_object_begin (json_ctx);
 142   json_attr_uint (json_ctx, "len_haystack", BUF1PAGES * page_size);
 143   json_attr_uint (json_ctx, "len_needle", len);
 144   json_attr_uint (json_ctx, "haystack_ptr", (uintptr_t) buf1);
 145   json_attr_uint (json_ctx, "needle_ptr", (uintptr_t) str);
 146   json_attr_uint (json_ctx, "fail", 0);
 147
 148   json_array_begin (json_ctx, "timings");
 149
 150   FOR_EACH_IMPL (impl, 0)
 151     do_one_test (json_ctx, impl, buf1, BUF1PAGES * page_size, str, len,
 152                  buf1 + idx);
 153
 154   memcpy (buf1 + idx, tmpbuf, len);
 155
 156   json_array_end (json_ctx);
 157   json_element_object_end (json_ctx);
 158 }
 159
 160 static void
 161 do_random_tests (json_ctx_t *json_ctx)
 162 {
 163   for (size_t n = 0; n < ITERATIONS; ++n)
 164     {
 165       char tmpbuf[32];
 166
 167       size_t shift = random () % 11;
 168       size_t rel = random () % ((2 << (shift + 1)) * 64);
 169       size_t idx = MIN ((2 << shift) * 64 + rel, BUF1PAGES * page_size - 2);
 170       size_t len = random () % (sizeof (tmpbuf) - 1) + 1;
 171       len = MIN (len, BUF1PAGES * page_size - idx - 1);
 172       memcpy (tmpbuf, buf1 + idx, len);
 173       for (size_t i = random () % len / 2 + 1; i > 0; --i)
 174         {
 175           size_t off = random () % len;
 176           char ch = '0' + random () % 10;
 177
 178           buf1[idx + off] = ch;
 179         }
 180
 181       json_element_object_begin (json_ctx);
 182       json_attr_uint (json_ctx, "len_haystack", BUF1PAGES * page_size);
 183       json_attr_uint (json_ctx, "len_needle", len);
 184       json_attr_uint (json_ctx, "haystack_ptr", (uintptr_t) buf1);
 185       json_attr_uint (json_ctx, "needle_ptr", (uintptr_t) (buf1 + idx));
 186       json_attr_uint (json_ctx, "fail", 0);
 187
 188       json_array_begin (json_ctx, "timings");
 189
 190       FOR_EACH_IMPL (impl, 0)
 191         do_one_test (json_ctx, impl, buf1, BUF1PAGES * page_size, buf1 + idx,
 192                      len, buf1 + idx);
 193
 194       json_array_end (json_ctx);
 195       json_element_object_end (json_ctx);
 196
 197       memcpy (buf1 + idx, tmpbuf, len);
 198     }
 199 }
 200
 201 static const char *const strs[] =
 202   {
 203     "00000", "00112233", "0123456789", "0000111100001111",
 204     "00000111110000022222", "012345678901234567890",
 205     "abc0", "aaaa0", "abcabc0"
 206   };
 207
 208 int
 209 test_main (void)
 210 {
 211   json_ctx_t json_ctx;
 212   size_t i;
 213
 214   test_init ();
 215   json_init (&json_ctx, 0, stdout);
 216
 217   json_document_begin (&json_ctx);
 218   json_attr_string (&json_ctx, "timing_type", TIMING_TYPE);
 219
 220   json_attr_object_begin (&json_ctx, "functions");
 221   json_attr_object_begin (&json_ctx, TEST_NAME);
 222   json_attr_string (&json_ctx, "bench-variant", "");
 223
 224   json_array_begin (&json_ctx, "ifuncs");
 225   FOR_EACH_IMPL (impl, 0)
 226     json_element_string (&json_ctx, impl->name);
 227   json_array_end (&json_ctx);
 228
 229   json_array_begin (&json_ctx, "results");
 230
 231   for (i = 0; i < BUF1PAGES * page_size; ++i)
 232     buf1[i] = 60 + random () % 32;
 233
 234   for (i = 0; i < sizeof (strs) / sizeof (strs[0]); ++i)
 235     for (size_t j = 0; j < 120; j += 7)
 236       {
 237         size_t len = strlen (strs[i]);
 238
 239         do_test (&json_ctx, strs[i], len, j);
 240       }
 241
 242   do_random_tests (&json_ctx);
 243
 244   json_array_end (&json_ctx);
 245   json_attr_object_end (&json_ctx);
 246   json_attr_object_end (&json_ctx);
 247   json_document_end (&json_ctx);
 248   return ret;
 249 }
 250
 251 #include <support/test-driver.c>