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glibc/benchtests/bench-strcmp.c

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/* Measure strcmp and wcscmp functions.
Copyright (C) 2013-2024 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
#ifdef WIDE
# define TEST_NAME "wcscmp"
#else
# define TEST_NAME "strcmp"
#endif
#include "bench-string.h"
#include "json-lib.h"
#ifdef WIDE
# define CHARBYTESLOG 2
# define MIDCHAR 0x7fffffff
# define LARGECHAR 0xfffffffe
#else
# define CHARBYTESLOG 0
# define MIDCHAR 0x7f
# define LARGECHAR 0xfe
int
generic_strcmp (const char *s1, const char *s2);
IMPL (generic_strcmp, 0)
#endif
typedef int (*proto_t) (const CHAR *, const CHAR *);
IMPL (STRCMP, 1)
static void
do_one_test (json_ctx_t *json_ctx, impl_t *impl,
const CHAR *s1, const CHAR *s2,
int exp_result)
{
size_t i, iters = INNER_LOOP_ITERS8 / 2;
timing_t start, stop, cur;
TIMING_NOW (start);
for (i = 0; i < iters; ++i)
{
CALL (impl, s1, s2);
}
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 align1, size_t align2, size_t len,
int max_char, int exp_result, int at_end)
{
size_t i;
CHAR *s1, *s2;
if (len == 0)
return;
align1 &= ~(CHARBYTES - 1);
align2 &= ~(CHARBYTES - 1);
align1 &= (getpagesize () - 1);
if (align1 + (len + 1) * CHARBYTES >= page_size)
return;
align2 &= (getpagesize () - 1);
if (align2 + (len + 1) * CHARBYTES >= page_size)
return;
/* Put them close to the end of page. */
if (at_end)
{
i = align1 + CHARBYTES * (len + 2);
align1 = ((page_size - i) / 16 * 16) + align1;
i = align2 + CHARBYTES * (len + 2);
align2 = ((page_size - i) / 16 * 16) + align2;
}
s1 = (CHAR *)(buf1 + align1);
s2 = (CHAR *)(buf2 + align2);
for (i = 0; i < len; i++)
s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % max_char;
s1[len] = s2[len] = 0;
s1[len + 1] = 23;
s2[len + 1] = 24 + exp_result;
s2[len - 1] -= exp_result;
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "length", (double)len);
json_attr_uint (json_ctx, "align1", (double)align1);
json_attr_uint (json_ctx, "align2", (double)align2);
json_array_begin (json_ctx, "timings");
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, s1, s2, exp_result);
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
static void
do_one_test_page_boundary (json_ctx_t *json_ctx, CHAR *s1, CHAR *s2,
size_t align1, size_t align2, size_t len,
int exp_result)
{
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "length", (double) len);
json_attr_uint (json_ctx, "align1", (double) align1);
json_attr_uint (json_ctx, "align2", (double) align2);
json_array_begin (json_ctx, "timings");
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, s1, s2, exp_result);
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
static void
do_test_page_boundary (json_ctx_t *json_ctx)
{
/* To trigger bug 25933, we need a size that is equal to the vector
length times 4. In the case of AVX2 for Intel, we need 32 * 4. We
make this test generic and run it for all architectures as additional
boundary testing for such related algorithms. */
size_t size = 32 * 4;
size_t len;
CHAR *s1 = (CHAR *) (buf1 + (BUF1PAGES - 1) * page_size);
CHAR *s2 = (CHAR *) (buf2 + (BUF1PAGES - 1) * page_size);
int exp_result;
memset (s1, 'a', page_size);
memset (s2, 'a', page_size);
s1[(page_size / CHARBYTES) - 1] = (CHAR) 0;
s2[(page_size / CHARBYTES) - 1] = (CHAR) 0;
/* Iterate over a size that is just below where we expect the bug to
trigger up to the size we expect will trigger the bug e.g. [99-128].
Likewise iterate the start of two strings between 30 and 31 bytes
away from the boundary to simulate alignment changes. */
for (size_t s = 99; s <= size; s++)
for (size_t s1a = 30; s1a < 32; s1a++)
for (size_t s2a = 30; s2a < 32; s2a++)
{
size_t align1 = (page_size / CHARBYTES - s) - s1a;
size_t align2 = (page_size / CHARBYTES - s) - s2a;
CHAR *s1p = s1 + align1;
CHAR *s2p = s2 + align2;
len = (page_size / CHARBYTES) - 1 - align1;
exp_result = STRCMP (s1p, s2p);
do_one_test_page_boundary (json_ctx, s1p, s2p, align1, align2,
len, exp_result);
}
}
int
test_main (void)
{
json_ctx_t json_ctx;
size_t i, j, k;
size_t pg_sz = getpagesize ();
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", "default");
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 (k = 0; k < 2; ++k)
{
for (i = 1; i < 32; ++i)
{
do_test (&json_ctx, CHARBYTES * i, CHARBYTES * i, i, MIDCHAR, 0, k);
do_test (&json_ctx, CHARBYTES * i, CHARBYTES * i, i, MIDCHAR, 1, k);
do_test (&json_ctx, CHARBYTES * i, CHARBYTES * i, i, MIDCHAR, -1, k);
}
for (i = 1; i <= 8192;)
{
/* No page crosses. */
do_test (&json_ctx, 0, 0, i, MIDCHAR, 0, k);
do_test (&json_ctx, i * CHARBYTES, 0, i, MIDCHAR, 0, k);
do_test (&json_ctx, 0, i * CHARBYTES, i, MIDCHAR, 0, k);
/* False page crosses. */
do_test (&json_ctx, pg_sz / 2, pg_sz / 2 - CHARBYTES, i, MIDCHAR, 0,
k);
do_test (&json_ctx, pg_sz / 2 - CHARBYTES, pg_sz / 2, i, MIDCHAR, 0,
k);
do_test (&json_ctx, pg_sz - (i * CHARBYTES), 0, i, MIDCHAR, 0, k);
do_test (&json_ctx, 0, pg_sz - (i * CHARBYTES), i, MIDCHAR, 0, k);
/* Real page cross. */
for (j = 16; j < 128; j += 16)
{
do_test (&json_ctx, pg_sz - j, 0, i, MIDCHAR, 0, k);
do_test (&json_ctx, 0, pg_sz - j, i, MIDCHAR, 0, k);
do_test (&json_ctx, pg_sz - j, pg_sz - j / 2, i, MIDCHAR, 0, k);
do_test (&json_ctx, pg_sz - j / 2, pg_sz - j, i, MIDCHAR, 0, k);
}
if (i < 32)
{
++i;
}
else if (i < 160)
{
i += 8;
}
else if (i < 512)
{
i += 32;
}
else
{
i *= 2;
}
}
for (i = 1; i < 10 + CHARBYTESLOG; ++i)
{
do_test (&json_ctx, 0, 0, 2 << i, MIDCHAR, 0, k);
do_test (&json_ctx, 0, 0, 2 << i, LARGECHAR, 0, k);
do_test (&json_ctx, 0, 0, 2 << i, MIDCHAR, 1, k);
do_test (&json_ctx, 0, 0, 2 << i, LARGECHAR, 1, k);
do_test (&json_ctx, 0, 0, 2 << i, MIDCHAR, -1, k);
do_test (&json_ctx, 0, 0, 2 << i, LARGECHAR, -1, k);
do_test (&json_ctx, 0, CHARBYTES * i, 2 << i, MIDCHAR, 1, k);
do_test (&json_ctx, CHARBYTES * i, CHARBYTES * (i + 1), 2 << i,
LARGECHAR, 1, k);
}
for (i = 1; i < 8; ++i)
{
do_test (&json_ctx, CHARBYTES * i, 2 * CHARBYTES * i, 8 << i,
MIDCHAR, 0, k);
do_test (&json_ctx, 2 * CHARBYTES * i, CHARBYTES * i, 8 << i,
LARGECHAR, 0, k);
do_test (&json_ctx, CHARBYTES * i, 2 * CHARBYTES * i, 8 << i,
MIDCHAR, 1, k);
do_test (&json_ctx, 2 * CHARBYTES * i, CHARBYTES * i, 8 << i,
LARGECHAR, 1, k);
do_test (&json_ctx, CHARBYTES * i, 2 * CHARBYTES * i, 8 << i,
MIDCHAR, -1, k);
do_test (&json_ctx, 2 * CHARBYTES * i, CHARBYTES * i, 8 << i,
LARGECHAR, -1, k);
}
}
do_test_page_boundary (&json_ctx);
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 STRCMP
# define STRCMP generic_strcmp
# include <string/strcmp.c>
#endif
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