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glibc/benchtests/bench-strncmp.c
Wilco Dijkstra d1c3c0e4fe Benchtests: Remove simple_str(n)cmp 
Instead of benchmarking slow byte oriented loops, include the optimized generic
strcmp/strncmp implementation.  Adjust iteration count to reduce benchmark time.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-03-08 18:36:11 +00:00

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/* Measure strncmp 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 "wcsncmp"
#else
# define TEST_NAME "strncmp"
#endif
#include "bench-string.h"
#include "json-lib.h"
#ifdef WIDE
# define STRDUP wcsdup
#else
# define STRDUP strdup
int
generic_strncmp (const char *s1, const char *s2, size_t n);
IMPL (generic_strncmp, 0)
#endif
typedef int (*proto_t) (const CHAR *, const CHAR *, size_t);
IMPL (STRNCMP, 1)
static void
do_one_test (json_ctx_t *json_ctx, impl_t *impl, const CHAR *s1, const CHAR
*s2, size_t n, int exp_result)
{
size_t i, iters = INNER_LOOP_ITERS;
timing_t start, stop, cur;
TIMING_NOW (start);
for (i = 0; i < iters; ++i)
{
CALL (impl, s1, s2, n);
}
TIMING_NOW (stop);
TIMING_DIFF (cur, start, stop);
json_element_double (json_ctx, (double) cur / (double) iters);
}
static void
do_test_limit (json_ctx_t *json_ctx, size_t align1, size_t align2, size_t len,
size_t n, int max_char, int exp_result)
{
size_t i, align_n;
CHAR *s1, *s2;
align1 &= 15;
align2 &= 15;
align_n = (page_size - n * CHARBYTES) & 15;
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "strlen", (double) len);
json_attr_uint (json_ctx, "len", (double) n);
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)
{
alloc_bufs ();
s1 = (CHAR *) (buf1 + page_size - n * CHARBYTES);
s2 = (CHAR *) (buf2 + page_size - n * CHARBYTES);
if (align1 < align_n)
s1 = (CHAR *) ((char *) s1 - (align_n - align1));
if (align2 < align_n)
s2 = (CHAR *) ((char *) s2 - (align_n - align2));
for (i = 0; i < n; i++)
s1[i] = s2[i] = 1 + 23 * i % max_char;
if (len < n)
{
s1[len] = 0;
s2[len] = 0;
if (exp_result < 0)
s2[len] = 32;
else if (exp_result > 0)
s1[len] = 64;
}
do_one_test (json_ctx, impl, s1, s2, n, exp_result);
}
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
static void
do_test (json_ctx_t *json_ctx, size_t align1, size_t align2, size_t len, size_t
n, int max_char, int exp_result)
{
size_t i;
CHAR *s1, *s2;
if (n == 0)
return;
align1 &= getpagesize () - 1;
if (align1 + (n + 1) * CHARBYTES >= page_size)
return;
align2 &= getpagesize () - 1;
if (align2 + (n + 1) * CHARBYTES >= page_size)
return;
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "strlen", (double)len);
json_attr_uint (json_ctx, "len", (double)n);
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)
{
alloc_bufs ();
s1 = (CHAR *)(buf1 + align1);
s2 = (CHAR *)(buf2 + align2);
for (i = 0; i < n; i++)
s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % max_char;
s1[n] = 24 + exp_result;
s2[n] = 23;
s1[len] = 0;
s2[len] = 0;
if (exp_result < 0)
s2[len] = 32;
else if (exp_result > 0)
s1[len] = 64;
if (len >= n)
s2[n - 1] -= exp_result;
do_one_test (json_ctx, impl, s1, s2, n, 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,
size_t n, int exp_result)
{
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "strlen", (double) len);
json_attr_uint (json_ctx, "len", (double) n);
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, n, 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;
/* 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 = STRNCMP (s1p, s2p, s);
do_one_test_page_boundary (json_ctx, s1p, s2p, align1, align2,
len, s, exp_result);
}
}
static void
do_one_test_page (json_ctx_t *json_ctx, size_t offset1, size_t offset2,
CHAR *s2)
{
CHAR *s1;
int exp_result;
if (offset1 * CHARBYTES >= page_size
|| offset2 * CHARBYTES >= page_size)
return;
s1 = (CHAR *) buf1;
s1 += offset1;
s2 += offset2;
size_t len = (page_size / CHARBYTES) - offset1;
exp_result= *s1;
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "strlen", (double) len);
json_attr_uint (json_ctx, "len", (double) page_size);
json_attr_uint (json_ctx, "align1", (double) offset1);
json_attr_uint (json_ctx, "align2", (double) offset2);
json_array_begin (json_ctx, "timings");
{
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, s1, s2, page_size, -exp_result);
}
json_array_end (json_ctx);
json_element_object_end (json_ctx);
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "strlen", (double) len);
json_attr_uint (json_ctx, "len", (double) page_size);
json_attr_uint (json_ctx, "align1", (double) offset1);
json_attr_uint (json_ctx, "align2", (double) offset2);
json_array_begin (json_ctx, "timings");
{
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, s1, s2, page_size, exp_result);
}
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
static void
do_test_page (json_ctx_t *json_ctx)
{
size_t i;
CHAR *s1, *s2;
s1 = (CHAR *) buf1;
/* Fill buf1 with 23. */
for (i = 0; i < (page_size / CHARBYTES) - 1; i++)
s1[i] = 23;
s1[i] = 0;
/* Make a copy of buf1. */
s2 = STRDUP (s1);
/* Test should terminate within the page boundary. */
for (i = 0; i < (108 / CHARBYTES); ++i)
do_one_test_page (json_ctx, ((page_size - 108) / CHARBYTES) + i,
((page_size - 1460) / CHARBYTES), s2);
free (s2);
}
int
test_main (void)
{
json_ctx_t json_ctx;
size_t i, j, len;
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 (i = 0; i < 16; ++i)
{
do_test (&json_ctx, 0, 0, 8, i, 127, 0);
do_test (&json_ctx, 0, 0, 8, i, 127, -1);
do_test (&json_ctx, 0, 0, 8, i, 127, 1);
do_test (&json_ctx, i, i, 8, i, 127, 0);
do_test (&json_ctx, i, i, 8, i, 127, 1);
do_test (&json_ctx, i, i, 8, i, 127, -1);
do_test (&json_ctx, i, 2 * i, 8, i, 127, 0);
do_test (&json_ctx, 2 * i, i, 8, i, 127, 1);
do_test (&json_ctx, i, 3 * i, 8, i, 127, -1);
do_test (&json_ctx, 0, 0, 8, i, 255, 0);
do_test (&json_ctx, 0, 0, 8, i, 255, -1);
do_test (&json_ctx, 0, 0, 8, i, 255, 1);
do_test (&json_ctx, i, i, 8, i, 255, 0);
do_test (&json_ctx, i, i, 8, i, 255, 1);
do_test (&json_ctx, i, i, 8, i, 255, -1);
do_test (&json_ctx, i, 2 * i, 8, i, 255, 0);
do_test (&json_ctx, 2 * i, i, 8, i, 255, 1);
do_test (&json_ctx, i, 3 * i, 8, i, 255, -1);
}
for (len = 0; len <= 128; len += 64)
{
for (i = 1; i <= 8192;)
{
/* No page crosses. */
do_test (&json_ctx, 0, 0, i, i + len, 127, 0);
do_test (&json_ctx, i * CHARBYTES, 0, i, i + len, 127, 0);
do_test (&json_ctx, 0, i * CHARBYTES, i, i + len, 127, 0);
/* False page crosses. */
do_test (&json_ctx, pg_sz / 2, pg_sz / 2 - CHARBYTES, i, i + len,
127, 0);
do_test (&json_ctx, pg_sz / 2 - CHARBYTES, pg_sz / 2, i, i + len,
127, 0);
do_test (&json_ctx, pg_sz - (i * CHARBYTES), 0, i, i + len, 127,
0);
do_test (&json_ctx, 0, pg_sz - (i * CHARBYTES), i, i + len, 127,
0);
/* Real page cross. */
for (j = 16; j < 128; j += 16)
{
do_test (&json_ctx, pg_sz - j, 0, i, i + len, 127, 0);
do_test (&json_ctx, 0, pg_sz - j, i, i + len, 127, 0);
do_test (&json_ctx, pg_sz - j, pg_sz - j / 2, i, i + len,
127, 0);
do_test (&json_ctx, pg_sz - j / 2, pg_sz - j, i, i + len,
127, 0);
}
if (i < 32)
{
++i;
}
else if (i < 160)
{
i += 8;
}
else if (i < 256)
{
i += 32;
}
else
{
i *= 2;
}
}
}
for (i = 1; i < 8; ++i)
{
do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 127, 0);
do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 127, 1);
do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 127, -1);
do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 255, 0);
do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 255, 1);
do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 255, -1);
do_test (&json_ctx, 8 - i, 2 * i, 8 << i, 16 << i, 127, 0);
do_test (&json_ctx, 8 - i, 2 * i, 8 << i, 16 << i, 127, 1);
do_test (&json_ctx, 2 * i, i, 8 << i, 16 << i, 255, 0);
do_test (&json_ctx, 2 * i, i, 8 << i, 16 << i, 255, 1);
}
do_test_limit (&json_ctx, 4, 0, 21, 20, 127, 0);
do_test_limit (&json_ctx, 0, 4, 21, 20, 127, 0);
do_test_limit (&json_ctx, 8, 0, 25, 24, 127, 0);
do_test_limit (&json_ctx, 0, 8, 25, 24, 127, 0);
for (i = 0; i < 8; ++i)
{
do_test_limit (&json_ctx, 0, 0, 17 - i, 16 - i, 127, 0);
do_test_limit (&json_ctx, 0, 0, 17 - i, 16 - i, 255, 0);
do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 127, 0);
do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 127, 1);
do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 127, -1);
do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 255, 0);
do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 255, 1);
do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 255, -1);
}
do_test_page_boundary (&json_ctx);
do_test_page (&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 STRNCMP
# define STRNCMP generic_strncmp
# define libc_hidden_builtin_def(X)
# include <string/strncmp.c>
#endif
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