benchtests/bench-strncmp.c

   1 /* Measure strncmp functions.
   2    Copyright (C) 2013-2023 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 #ifdef WIDE
  21 # define TEST_NAME "wcsncmp"
  22 #else
  23 # define TEST_NAME "strncmp"
  24 #endif /* !WIDE */
  25 #include "bench-string.h"
  26 #include "json-lib.h"
  27
  28 #ifdef WIDE
  29 # define L(str) L##str
  30 # define STRDUP wcsdup
  31 # define SIMPLE_STRNCMP simple_wcsncmp
  32
  33 /* Wcsncmp uses signed semantics for comparison, not unsigned.
  34    Avoid using substraction since possible overflow.  */
  35 int
  36 simple_wcsncmp (const CHAR *s1, const CHAR *s2, size_t n)
  37 {
  38   wchar_t c1, c2;
  39
  40   while (n--)
  41     {
  42       c1 = *s1++;
  43       c2 = *s2++;
  44       if (c1 == L ('\0') || c1 != c2)
  45         return c1 > c2 ? 1 : (c1 < c2 ? -1 : 0);
  46     }
  47   return 0;
  48 }
  49
  50 #else
  51 # define L(str) str
  52 # define STRDUP strdup
  53 # define SIMPLE_STRNCMP simple_strncmp
  54
  55 /* Strncmp uses unsigned semantics for comparison.  */
  56 int
  57 simple_strncmp (const char *s1, const char *s2, size_t n)
  58 {
  59   int ret = 0;
  60
  61   while (n-- && (ret = *(unsigned char *) s1 - * (unsigned char *) s2++) == 0
  62          && *s1++);
  63   return ret;
  64 }
  65
  66 #endif /* !WIDE */
  67
  68 typedef int (*proto_t) (const CHAR *, const CHAR *, size_t);
  69
  70 IMPL (SIMPLE_STRNCMP, 0)
  71 IMPL (STRNCMP, 1)
  72
  73
  74 static void
  75 do_one_test (json_ctx_t *json_ctx, impl_t *impl, const CHAR *s1, const CHAR
  76              *s2, size_t n, int exp_result)
  77 {
  78   size_t i, iters = INNER_LOOP_ITERS8;
  79   timing_t start, stop, cur;
  80
  81   TIMING_NOW (start);
  82   for (i = 0; i < iters; ++i)
  83     {
  84       CALL (impl, s1, s2, n);
  85     }
  86   TIMING_NOW (stop);
  87
  88   TIMING_DIFF (cur, start, stop);
  89
  90   json_element_double (json_ctx, (double) cur / (double) iters);
  91 }
  92
  93 static void
  94 do_test_limit (json_ctx_t *json_ctx, size_t align1, size_t align2, size_t len,
  95                size_t n, int max_char, int exp_result)
  96 {
  97   size_t i, align_n;
  98   CHAR *s1, *s2;
  99
 100   align1 &= 15;
 101   align2 &= 15;
 102   align_n = (page_size - n * CHARBYTES) & 15;
 103
 104   json_element_object_begin (json_ctx);
 105   json_attr_uint (json_ctx, "strlen", (double) len);
 106   json_attr_uint (json_ctx, "len", (double) n);
 107   json_attr_uint (json_ctx, "align1", (double) align1);
 108   json_attr_uint (json_ctx, "align2", (double) align2);
 109   json_array_begin (json_ctx, "timings");
 110
 111   FOR_EACH_IMPL (impl, 0)
 112     {
 113       alloc_bufs ();
 114       s1 = (CHAR *) (buf1 + page_size - n * CHARBYTES);
 115       s2 = (CHAR *) (buf2 + page_size - n * CHARBYTES);
 116
 117       if (align1 < align_n)
 118         s1 = (CHAR *) ((char *) s1 - (align_n - align1));
 119
 120       if (align2 < align_n)
 121         s2 = (CHAR *) ((char *) s2 - (align_n - align2));
 122
 123       for (i = 0; i < n; i++)
 124         s1[i] = s2[i] = 1 + 23 * i % max_char;
 125
 126       if (len < n)
 127         {
 128           s1[len] = 0;
 129           s2[len] = 0;
 130           if (exp_result < 0)
 131             s2[len] = 32;
 132           else if (exp_result > 0)
 133             s1[len] = 64;
 134         }
 135
 136       do_one_test (json_ctx, impl, s1, s2, n, exp_result);
 137     }
 138
 139   json_array_end (json_ctx);
 140   json_element_object_end (json_ctx);
 141 }
 142
 143 static void
 144 do_test (json_ctx_t *json_ctx, size_t align1, size_t align2, size_t len, size_t
 145          n, int max_char, int exp_result)
 146 {
 147   size_t i;
 148   CHAR *s1, *s2;
 149
 150   if (n == 0)
 151     return;
 152
 153   align1 &= getpagesize () - 1;
 154   if (align1 + (n + 1) * CHARBYTES >= page_size)
 155     return;
 156
 157   align2 &= getpagesize () - 1;
 158   if (align2 + (n + 1) * CHARBYTES >= page_size)
 159     return;
 160
 161   json_element_object_begin (json_ctx);
 162   json_attr_uint (json_ctx, "strlen", (double)len);
 163   json_attr_uint (json_ctx, "len", (double)n);
 164   json_attr_uint (json_ctx, "align1", (double)align1);
 165   json_attr_uint (json_ctx, "align2", (double)align2);
 166   json_array_begin (json_ctx, "timings");
 167
 168   FOR_EACH_IMPL (impl, 0)
 169   {
 170     alloc_bufs ();
 171     s1 = (CHAR *)(buf1 + align1);
 172     s2 = (CHAR *)(buf2 + align2);
 173
 174     for (i = 0; i < n; i++)
 175       s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % max_char;
 176
 177     s1[n] = 24 + exp_result;
 178     s2[n] = 23;
 179     s1[len] = 0;
 180     s2[len] = 0;
 181     if (exp_result < 0)
 182       s2[len] = 32;
 183     else if (exp_result > 0)
 184       s1[len] = 64;
 185     if (len >= n)
 186       s2[n - 1] -= exp_result;
 187
 188     do_one_test (json_ctx, impl, s1, s2, n, exp_result);
 189   }
 190
 191   json_array_end (json_ctx);
 192   json_element_object_end (json_ctx);
 193 }
 194
 195 static void
 196 do_one_test_page_boundary (json_ctx_t *json_ctx, CHAR *s1, CHAR *s2,
 197                            size_t align1, size_t align2, size_t len,
 198                            size_t n, int exp_result)
 199 {
 200   json_element_object_begin (json_ctx);
 201   json_attr_uint (json_ctx, "strlen", (double) len);
 202   json_attr_uint (json_ctx, "len", (double) n);
 203   json_attr_uint (json_ctx, "align1", (double) align1);
 204   json_attr_uint (json_ctx, "align2", (double) align2);
 205   json_array_begin (json_ctx, "timings");
 206   FOR_EACH_IMPL (impl, 0)
 207     do_one_test (json_ctx, impl, s1, s2, n, exp_result);
 208   json_array_end (json_ctx);
 209   json_element_object_end (json_ctx);
 210 }
 211
 212 static void
 213 do_test_page_boundary (json_ctx_t *json_ctx)
 214 {
 215   /* To trigger bug 25933, we need a size that is equal to the vector
 216      length times 4. In the case of AVX2 for Intel, we need 32 * 4.  We
 217      make this test generic and run it for all architectures as additional
 218      boundary testing for such related algorithms.  */
 219   size_t size = 32 * 4;
 220   size_t len;
 221   CHAR *s1 = (CHAR *) (buf1 + (BUF1PAGES - 1) * page_size);
 222   CHAR *s2 = (CHAR *) (buf2 + (BUF1PAGES - 1) * page_size);
 223   int exp_result;
 224
 225   memset (s1, 'a', page_size);
 226   memset (s2, 'a', page_size);
 227
 228   s1[(page_size / CHARBYTES) - 1] = (CHAR) 0;
 229
 230   /* Iterate over a size that is just below where we expect the bug to
 231      trigger up to the size we expect will trigger the bug e.g. [99-128].
 232      Likewise iterate the start of two strings between 30 and 31 bytes
 233      away from the boundary to simulate alignment changes.  */
 234   for (size_t s = 99; s <= size; s++)
 235     for (size_t s1a = 30; s1a < 32; s1a++)
 236       for (size_t s2a = 30; s2a < 32; s2a++)
 237         {
 238           size_t align1 = (page_size / CHARBYTES - s) - s1a;
 239           size_t align2 = (page_size / CHARBYTES - s) - s2a;
 240           CHAR *s1p = s1 + align1;
 241           CHAR *s2p = s2 + align2;
 242           len = (page_size / CHARBYTES) - 1 - align1;
 243           exp_result = SIMPLE_STRNCMP (s1p, s2p, s);
 244           do_one_test_page_boundary (json_ctx, s1p, s2p, align1, align2,
 245                                      len, s, exp_result);
 246         }
 247 }
 248
 249 static void
 250 do_one_test_page (json_ctx_t *json_ctx, size_t offset1, size_t offset2,
 251                   CHAR *s2)
 252 {
 253   CHAR *s1;
 254   int exp_result;
 255
 256   if (offset1 * CHARBYTES  >= page_size
 257       || offset2 * CHARBYTES >= page_size)
 258     return;
 259
 260   s1 = (CHAR *) buf1;
 261   s1 += offset1;
 262   s2 += offset2;
 263
 264   size_t len = (page_size / CHARBYTES) - offset1;
 265
 266   exp_result= *s1;
 267
 268   json_element_object_begin (json_ctx);
 269   json_attr_uint (json_ctx, "strlen", (double) len);
 270   json_attr_uint (json_ctx, "len", (double) page_size);
 271   json_attr_uint (json_ctx, "align1", (double) offset1);
 272   json_attr_uint (json_ctx, "align2", (double) offset2);
 273   json_array_begin (json_ctx, "timings");
 274   {
 275     FOR_EACH_IMPL (impl, 0)
 276       do_one_test (json_ctx, impl, s1, s2, page_size, -exp_result);
 277   }
 278   json_array_end (json_ctx);
 279   json_element_object_end (json_ctx);
 280
 281   json_element_object_begin (json_ctx);
 282   json_attr_uint (json_ctx, "strlen", (double) len);
 283   json_attr_uint (json_ctx, "len", (double) page_size);
 284   json_attr_uint (json_ctx, "align1", (double) offset1);
 285   json_attr_uint (json_ctx, "align2", (double) offset2);
 286   json_array_begin (json_ctx, "timings");
 287   {
 288     FOR_EACH_IMPL (impl, 0)
 289       do_one_test (json_ctx, impl, s1, s2, page_size, exp_result);
 290   }
 291   json_array_end (json_ctx);
 292   json_element_object_end (json_ctx);
 293 }
 294
 295 static void
 296 do_test_page (json_ctx_t *json_ctx)
 297 {
 298   size_t i;
 299   CHAR *s1, *s2;
 300
 301   s1 = (CHAR *) buf1;
 302   /* Fill buf1 with 23. */
 303   for (i = 0; i < (page_size / CHARBYTES) - 1; i++)
 304     s1[i] = 23;
 305   s1[i] = 0;
 306
 307   /* Make a copy of buf1.  */
 308   s2 = STRDUP (s1);
 309
 310   /* Test should terminate within the page boundary.  */
 311   for (i = 0; i < (108 / CHARBYTES); ++i)
 312     do_one_test_page (json_ctx, ((page_size - 108) / CHARBYTES) + i,
 313                       ((page_size - 1460) / CHARBYTES), s2);
 314
 315   free (s2);
 316 }
 317
 318 int
 319 test_main (void)
 320 {
 321   json_ctx_t json_ctx;
 322   size_t i, j, len;
 323   size_t pg_sz = getpagesize ();
 324
 325   test_init ();
 326
 327   json_init (&json_ctx, 0, stdout);
 328
 329   json_document_begin (&json_ctx);
 330   json_attr_string (&json_ctx, "timing_type", TIMING_TYPE);
 331
 332   json_attr_object_begin (&json_ctx, "functions");
 333   json_attr_object_begin (&json_ctx, TEST_NAME);
 334   json_attr_string (&json_ctx, "bench-variant", "default");
 335
 336   json_array_begin (&json_ctx, "ifuncs");
 337   FOR_EACH_IMPL (impl, 0)
 338   json_element_string (&json_ctx, impl->name);
 339   json_array_end (&json_ctx);
 340
 341   json_array_begin (&json_ctx, "results");
 342
 343   for (i = 0; i < 16; ++i)
 344     {
 345       do_test (&json_ctx, 0, 0, 8, i, 127, 0);
 346       do_test (&json_ctx, 0, 0, 8, i, 127, -1);
 347       do_test (&json_ctx, 0, 0, 8, i, 127, 1);
 348       do_test (&json_ctx, i, i, 8, i, 127, 0);
 349       do_test (&json_ctx, i, i, 8, i, 127, 1);
 350       do_test (&json_ctx, i, i, 8, i, 127, -1);
 351       do_test (&json_ctx, i, 2 * i, 8, i, 127, 0);
 352       do_test (&json_ctx, 2 * i, i, 8, i, 127, 1);
 353       do_test (&json_ctx, i, 3 * i, 8, i, 127, -1);
 354       do_test (&json_ctx, 0, 0, 8, i, 255, 0);
 355       do_test (&json_ctx, 0, 0, 8, i, 255, -1);
 356       do_test (&json_ctx, 0, 0, 8, i, 255, 1);
 357       do_test (&json_ctx, i, i, 8, i, 255, 0);
 358       do_test (&json_ctx, i, i, 8, i, 255, 1);
 359       do_test (&json_ctx, i, i, 8, i, 255, -1);
 360       do_test (&json_ctx, i, 2 * i, 8, i, 255, 0);
 361       do_test (&json_ctx, 2 * i, i, 8, i, 255, 1);
 362       do_test (&json_ctx, i, 3 * i, 8, i, 255, -1);
 363     }
 364
 365   for (len = 0; len <= 128; len += 64)
 366     {
 367       for (i = 1; i <= 8192;)
 368         {
 369           /* No page crosses.  */
 370           do_test (&json_ctx, 0, 0, i, i + len, 127, 0);
 371           do_test (&json_ctx, i * CHARBYTES, 0, i, i + len, 127, 0);
 372           do_test (&json_ctx, 0, i * CHARBYTES, i, i + len, 127, 0);
 373
 374           /* False page crosses.  */
 375           do_test (&json_ctx, pg_sz / 2, pg_sz / 2 - CHARBYTES, i, i + len,
 376                    127, 0);
 377           do_test (&json_ctx, pg_sz / 2 - CHARBYTES, pg_sz / 2, i, i + len,
 378                    127, 0);
 379
 380           do_test (&json_ctx, pg_sz - (i * CHARBYTES), 0, i, i + len, 127,
 381                    0);
 382           do_test (&json_ctx, 0, pg_sz - (i * CHARBYTES), i, i + len, 127,
 383                    0);
 384
 385           /* Real page cross.  */
 386           for (j = 16; j < 128; j += 16)
 387             {
 388               do_test (&json_ctx, pg_sz - j, 0, i, i + len, 127, 0);
 389               do_test (&json_ctx, 0, pg_sz - j, i, i + len, 127, 0);
 390
 391               do_test (&json_ctx, pg_sz - j, pg_sz - j / 2, i, i + len,
 392                        127, 0);
 393               do_test (&json_ctx, pg_sz - j / 2, pg_sz - j, i, i + len,
 394                        127, 0);
 395             }
 396
 397           if (i < 32)
 398             {
 399               ++i;
 400             }
 401           else if (i < 160)
 402             {
 403               i += 8;
 404             }
 405           else if (i < 256)
 406             {
 407               i += 32;
 408             }
 409           else
 410             {
 411               i *= 2;
 412             }
 413         }
 414     }
 415
 416   for (i = 1; i < 8; ++i)
 417     {
 418       do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 127, 0);
 419       do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 127, 1);
 420       do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 127, -1);
 421       do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 255, 0);
 422       do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 255, 1);
 423       do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 255, -1);
 424       do_test (&json_ctx, 8 - i, 2 * i, 8 << i, 16 << i, 127, 0);
 425       do_test (&json_ctx, 8 - i, 2 * i, 8 << i, 16 << i, 127, 1);
 426       do_test (&json_ctx, 2 * i, i, 8 << i, 16 << i, 255, 0);
 427       do_test (&json_ctx, 2 * i, i, 8 << i, 16 << i, 255, 1);
 428     }
 429
 430   do_test_limit (&json_ctx, 4, 0, 21, 20, 127, 0);
 431   do_test_limit (&json_ctx, 0, 4, 21, 20, 127, 0);
 432   do_test_limit (&json_ctx, 8, 0, 25, 24, 127, 0);
 433   do_test_limit (&json_ctx, 0, 8, 25, 24, 127, 0);
 434
 435   for (i = 0; i < 8; ++i)
 436     {
 437       do_test_limit (&json_ctx, 0, 0, 17 - i, 16 - i, 127, 0);
 438       do_test_limit (&json_ctx, 0, 0, 17 - i, 16 - i, 255, 0);
 439       do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 127, 0);
 440       do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 127, 1);
 441       do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 127, -1);
 442       do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 255, 0);
 443       do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 255, 1);
 444       do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 255, -1);
 445     }
 446
 447   do_test_page_boundary (&json_ctx);
 448   do_test_page (&json_ctx);
 449
 450   json_array_end (&json_ctx);
 451   json_attr_object_end (&json_ctx);
 452   json_attr_object_end (&json_ctx);
 453   json_document_end (&json_ctx);
 454
 455   return ret;
 456 }
 457
 458 #include <support/test-driver.c>