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glibc/benchtests/bench-strchr.c
Paul Eggert 2642002380 Update copyright dates with scripts/update-copyrights
2025-01-01 11:22:09 -08:00

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/* Measure STRCHR functions.
Copyright (C) 2013-2025 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
<https://www.gnu.org/licenses/>. */
#define TEST_MAIN
#ifndef WIDE
# ifdef USE_FOR_STRCHRNUL
# define TEST_NAME "strchrnul"
# else
# define TEST_NAME "strchr"
# endif /* !USE_FOR_STRCHRNUL */
#else
# ifdef USE_FOR_STRCHRNUL
# define TEST_NAME "wcschrnul"
# else
# define TEST_NAME "wcschr"
# endif /* !USE_FOR_STRCHRNUL */
#endif /* WIDE */
#include "bench-string.h"
#include "json-lib.h"
#define BIG_CHAR MAX_CHAR
#ifndef WIDE
# ifdef USE_FOR_STRCHRNUL
# undef STRCHR
# define STRCHR strchrnul
# endif /* !USE_FOR_STRCHRNUL */
# define MIDDLE_CHAR 127
# define SMALL_CHAR 23
#else
# ifdef USE_FOR_STRCHRNUL
# undef STRCHR
# define STRCHR wcschrnul
# endif /* !USE_FOR_STRCHRNUL */
# define MIDDLE_CHAR 1121
# define SMALL_CHAR 851
#endif /* WIDE */
#ifdef USE_FOR_STRCHRNUL
# define DO_RAND_TEST(...)
#else
# define DO_RAND_TEST(...) do_rand_test(__VA_ARGS__)
#endif
#ifdef USE_FOR_STRCHRNUL
# define NULLRET(endptr) endptr
#else
# define NULLRET(endptr) NULL
#endif /* !USE_FOR_STRCHRNUL */
typedef CHAR *(*proto_t) (const CHAR *, int);
IMPL (STRCHR, 1)
#ifndef WIDE
char *generic_strchr (const char *, int);
char *generic_strchrnul (const char *, int);
# ifndef USE_FOR_STRCHRNUL
IMPL (generic_strchr, 0)
# else
IMPL (generic_strchrnul, 0)
# endif
#endif
#ifndef USE_FOR_STRCHRNUL
/* Random benchmarks for strchr (if return is CHAR or NULL). The
rational for the benchmark is returning null/char can be done with
predicate execution (i.e cmovcc on x86) or a branch. */
/* Large enough that full history can't be stored in BHT. */
#define NUM_SEARCH_CHARS 2048
/* Expectation is usecases of strchr check the return. Otherwise
strchrnul would almost always be better. Since there is another
branch coming we want to test the case where a potential branch in
strchr can be used to skip a later mispredict because of the
relationship between the two branches. */
static void __attribute_optimization_barrier__
do_one_rand_plus_branch_test (json_ctx_t *json_ctx, impl_t *impl,
const CHAR *s, const CHAR *c)
{
size_t i, iters = INNER_LOOP_ITERS8;
int must_execute = 0;
timing_t start, stop, cur;
TIMING_NOW (start);
for (i = 0; i < iters; ++i)
{
if (CALL (impl, s, c[i % NUM_SEARCH_CHARS]))
{
/* We just need something that will force compiler to emit
a branch instead of conditional execution. */
++must_execute;
asm volatile("" : : :);
}
}
TIMING_NOW (stop);
TIMING_DIFF (cur, start, stop);
json_element_double (json_ctx, (double)cur / (double)iters);
}
static void __attribute_optimization_barrier__
do_one_rand_test (json_ctx_t *json_ctx, impl_t *impl, const CHAR *s,
const CHAR *c)
{
size_t i, iters = INNER_LOOP_ITERS8;
timing_t start, stop, cur;
TIMING_NOW (start);
for (i = 0; i < iters; ++i)
{
CALL (impl, s, c[i % NUM_SEARCH_CHARS]);
}
TIMING_NOW (stop);
TIMING_DIFF (cur, start, stop);
json_element_double (json_ctx, (double)cur / (double)iters);
}
static void
do_rand_test (json_ctx_t *json_ctx, size_t align, size_t pos, size_t len,
float perc_zero)
{
size_t i;
int perc_zero_int;
CHAR *buf = (CHAR *)buf1;
CHAR *c = (CHAR *)buf2;
align &= 127;
if ((align + len) * sizeof (CHAR) >= page_size)
return;
/* Test is only interesting if we can hit both cases. */
if (pos >= len)
return;
/* Segfault if we run the test. */
if (NUM_SEARCH_CHARS * sizeof (CHAR) > page_size)
return;
for (i = 0; i < len; ++i)
{
buf[align + i] = 2;
}
buf[align + len] = 0;
buf[align + pos] = 1;
perc_zero_int = perc_zero * RAND_MAX;
for (i = 0; i < NUM_SEARCH_CHARS; ++i)
{
if (rand () > perc_zero_int)
c[i] = 0;
else
c[i] = 1;
}
{
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "rand", 1);
json_attr_uint (json_ctx, "branch", 1);
json_attr_double (json_ctx, "perc-zero", perc_zero);
json_attr_uint (json_ctx, "length", len);
json_attr_uint (json_ctx, "pos", pos);
json_attr_uint (json_ctx, "alignment", align);
json_array_begin (json_ctx, "timings");
FOR_EACH_IMPL (impl, 0)
do_one_rand_plus_branch_test (json_ctx, impl, buf + align, c);
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
{
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "rand", 1);
json_attr_uint (json_ctx, "branch", 0);
json_attr_double (json_ctx, "perc-zero", perc_zero);
json_attr_uint (json_ctx, "length", len);
json_attr_uint (json_ctx, "pos", pos);
json_attr_uint (json_ctx, "alignment", align);
json_array_begin (json_ctx, "timings");
FOR_EACH_IMPL (impl, 0)
do_one_rand_test (json_ctx, impl, buf + align, c);
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
}
#endif
static void
do_one_test (json_ctx_t *json_ctx, impl_t *impl, const CHAR *s, int c,
const CHAR *exp_res)
{
size_t i, iters = INNER_LOOP_ITERS8;
timing_t start, stop, cur;
const CHAR *res = CALL (impl, s, c);
if (res != exp_res)
{
error (0, 0, "Wrong result in function %s %p != %p", impl->name, res,
exp_res);
ret = 1;
return;
}
TIMING_NOW (start);
for (i = 0; i < iters; ++i)
{
CALL (impl, s, c);
}
TIMING_NOW (stop);
TIMING_DIFF (cur, start, stop);
json_element_double (json_ctx, (double)cur / (double)iters);
}
static void
do_test (json_ctx_t *json_ctx, size_t align, size_t pos, size_t len,
int seek_char, int max_char)
/* For wcschr: align here means align not in bytes,
but in wchar_ts, in bytes it will equal to align * (sizeof (wchar_t))
len for wcschr here isn't in bytes but it's number of wchar_t symbols. */
{
size_t i;
CHAR *result;
CHAR *buf = (CHAR *) buf1;
align &= 127;
if ((align + len) * sizeof (CHAR) >= page_size)
return;
for (i = 0; i < len; ++i)
{
buf[align + i] = 32 + 23 * i % max_char;
if (buf[align + i] == seek_char)
buf[align + i] = seek_char + 1;
else if (buf[align + i] == 0)
buf[align + i] = 1;
}
buf[align + len] = 0;
if (pos < len)
{
buf[align + pos] = seek_char;
result = buf + align + pos;
}
else if (seek_char == 0)
result = buf + align + len;
else
result = NULLRET (buf + align + len);
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "rand", 0);
json_attr_uint (json_ctx, "length", len);
json_attr_uint (json_ctx, "pos", pos);
json_attr_uint (json_ctx, "seek_char", seek_char);
json_attr_uint (json_ctx, "max_char", max_char);
json_attr_uint (json_ctx, "alignment", align);
json_array_begin (json_ctx, "timings");
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, buf + align, seek_char, result);
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
int
test_main (void)
{
json_ctx_t json_ctx;
size_t i, j;
test_init ();
json_init (&json_ctx, 0, stdout);
json_document_begin (&json_ctx);
json_attr_string (&json_ctx, "timing_type", TIMING_TYPE);
json_attr_object_begin (&json_ctx, "functions");
json_attr_object_begin (&json_ctx, TEST_NAME);
json_attr_string (&json_ctx, "bench-variant", "");
json_array_begin (&json_ctx, "ifuncs");
FOR_EACH_IMPL (impl, 0)
json_element_string (&json_ctx, impl->name);
json_array_end (&json_ctx);
json_array_begin (&json_ctx, "results");
for (i = 1; i < 8; ++i)
{
do_test (&json_ctx, 0, 16 << i, 2048, SMALL_CHAR, MIDDLE_CHAR);
do_test (&json_ctx, i, 16 << i, 2048, SMALL_CHAR, MIDDLE_CHAR);
}
for (i = 1; i < 8; ++i)
{
do_test (&json_ctx, 0, 16 << i, 4096, SMALL_CHAR, MIDDLE_CHAR);
do_test (&json_ctx, i, 16 << i, 4096, SMALL_CHAR, MIDDLE_CHAR);
}
for (i = 1; i < 8; ++i)
{
do_test (&json_ctx, i, 64, 256, SMALL_CHAR, MIDDLE_CHAR);
do_test (&json_ctx, i, 64, 256, SMALL_CHAR, BIG_CHAR);
}
for (i = 0; i < 8; ++i)
{
do_test (&json_ctx, 16 * i, 256, 512, SMALL_CHAR, MIDDLE_CHAR);
do_test (&json_ctx, 16 * i, 256, 512, SMALL_CHAR, BIG_CHAR);
}
for (i = 0; i < 32; ++i)
{
do_test (&json_ctx, 0, i, i + 1, SMALL_CHAR, MIDDLE_CHAR);
do_test (&json_ctx, 0, i, i + 1, SMALL_CHAR, BIG_CHAR);
}
for (i = 1; i < 8; ++i)
{
do_test (&json_ctx, 0, 16 << i, 2048, 0, MIDDLE_CHAR);
do_test (&json_ctx, i, 16 << i, 2048, 0, MIDDLE_CHAR);
}
for (i = 1; i < 8; ++i)
{
do_test (&json_ctx, 0, 16 << i, 4096, 0, MIDDLE_CHAR);
do_test (&json_ctx, i, 16 << i, 4096, 0, MIDDLE_CHAR);
}
for (i = 1; i < 8; ++i)
{
do_test (&json_ctx, i, 64, 256, 0, MIDDLE_CHAR);
do_test (&json_ctx, i, 64, 256, 0, BIG_CHAR);
}
for (i = 0; i < 8; ++i)
{
do_test (&json_ctx, 16 * i, 256, 512, 0, MIDDLE_CHAR);
do_test (&json_ctx, 16 * i, 256, 512, 0, BIG_CHAR);
}
for (i = 0; i < 32; ++i)
{
do_test (&json_ctx, 0, i, i + 1, 0, MIDDLE_CHAR);
do_test (&json_ctx, 0, i, i + 1, 0, BIG_CHAR);
}
for (i = 16 / sizeof (CHAR); i <= 8192 / sizeof (CHAR); i += i)
{
for (j = 32 / sizeof (CHAR); j <= 320 / sizeof (CHAR);
j += 32 / sizeof (CHAR))
{
do_test (&json_ctx, 0, i, i + j, 0, MIDDLE_CHAR);
do_test (&json_ctx, 0, i + j, i, 0, MIDDLE_CHAR);
if (i > j)
{
do_test (&json_ctx, 0, i, i - j, 0, MIDDLE_CHAR);
do_test (&json_ctx, 0, i - j, i, 0, MIDDLE_CHAR);
}
}
}
DO_RAND_TEST (&json_ctx, 0, 15, 16, 0.0);
DO_RAND_TEST (&json_ctx, 0, 15, 16, 0.1);
DO_RAND_TEST (&json_ctx, 0, 15, 16, 0.25);
DO_RAND_TEST (&json_ctx, 0, 15, 16, 0.33);
DO_RAND_TEST (&json_ctx, 0, 15, 16, 0.5);
DO_RAND_TEST (&json_ctx, 0, 15, 16, 0.66);
DO_RAND_TEST (&json_ctx, 0, 15, 16, 0.75);
DO_RAND_TEST (&json_ctx, 0, 15, 16, 0.9);
DO_RAND_TEST (&json_ctx, 0, 15, 16, 1.0);
json_array_end (&json_ctx);
json_attr_object_end (&json_ctx);
json_attr_object_end (&json_ctx);
json_document_end (&json_ctx);
return ret;
}
#include <support/test-driver.c>
#ifndef WIDE
# undef STRCHRNUL
# define STRCHRNUL generic_strchrnul
# undef STRCHR
# define STRCHR generic_strchr
# include <string/strchrnul.c>
# include <string/strchr.c>
#endif
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