glibc/benchtests/bench-strcmp.c
Wilco Dijkstra 2623479105 Benchtests: Adjust timing
Adjust iteration counts so benchmarks don't run too slowly or quickly.
Ensure benchmarks take less than 10 seconds on older, slower cores and
more than 0.5 seconds on fast cores.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-04-17 13:00:38 +01:00

300 lines
8.8 KiB
C

/* Measure strcmp and wcscmp functions.
Copyright (C) 2013-2023 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