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/* Measure strlen performance.
Copyright (C) 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
#define TEST_NAME "strlen"
#define NUM_TESTS 65536
#define MAX_ALIGN 32
#define MAX_STRLEN 128
#define MIN_PAGE_SIZE (2 * getpagesize())
#include "bench-string.h"
#include <assert.h>
#include "json-lib.h"
typedef size_t (*proto_t) (const CHAR *);
size_t memchr_strlen (const CHAR *);
IMPL (memchr_strlen, 0)
size_t
memchr_strlen (const CHAR *p)
{
return (const CHAR *)MEMCHR (p, 0, PTRDIFF_MAX) - p;
}
IMPL (STRLEN, 1)
static uint32_t strlen_tests[NUM_TESTS];
typedef struct { uint16_t size; uint16_t freq; } freq_data_t;
typedef struct { uint16_t align; uint16_t freq; } align_data_t;
#define SIZE_NUM 65536
#define SIZE_MASK (SIZE_NUM-1)
static uint8_t strlen_len_arr[SIZE_NUM];
/* Frequency data for strlen sizes up to 256 based on SPEC2017. */
static freq_data_t strlen_len_freq[] =
{
{ 12,22671}, { 18,12834}, { 13, 9555}, { 6, 6348}, { 17, 6095}, { 11, 2115},
{ 10, 1335}, { 7, 814}, { 2, 646}, { 9, 483}, { 8, 471}, { 16, 418},
{ 4, 390}, { 1, 388}, { 5, 233}, { 3, 204}, { 0, 79}, { 14, 79},
{ 15, 69}, { 26, 36}, { 22, 35}, { 31, 24}, { 32, 24}, { 19, 21},
{ 25, 17}, { 28, 15}, { 21, 14}, { 33, 14}, { 20, 13}, { 24, 9},
{ 29, 9}, { 30, 9}, { 23, 7}, { 34, 7}, { 27, 6}, { 44, 5},
{ 42, 4}, { 45, 3}, { 47, 3}, { 40, 2}, { 41, 2}, { 43, 2},
{ 58, 2}, { 78, 2}, { 36, 2}, { 48, 1}, { 52, 1}, { 60, 1},
{ 64, 1}, { 56, 1}, { 76, 1}, { 68, 1}, { 80, 1}, { 84, 1},
{ 72, 1}, { 86, 1}, { 35, 1}, { 39, 1}, { 50, 1}, { 38, 1},
{ 37, 1}, { 46, 1}, { 98, 1}, {102, 1}, {128, 1}, { 51, 1},
{107, 1}, { 0, 0}
};
#define ALIGN_NUM 1024
#define ALIGN_MASK (ALIGN_NUM-1)
static uint8_t strlen_align_arr[ALIGN_NUM];
/* Alignment data for strlen based on SPEC2017. */
static align_data_t string_align_freq[] =
{
{8, 470}, {32, 427}, {16, 99}, {1, 19}, {2, 6}, {4, 3}, {0, 0}
};
static void
init_strlen_distribution (void)
{
int i, j, freq, size, n;
for (n = i = 0; (freq = strlen_len_freq[i].freq) != 0; i++)
for (j = 0, size = strlen_len_freq[i].size; j < freq; j++)
strlen_len_arr[n++] = size;
assert (n == SIZE_NUM);
for (n = i = 0; (freq = string_align_freq[i].freq) != 0; i++)
for (j = 0, size = string_align_freq[i].align; j < freq; j++)
strlen_align_arr[n++] = size;
assert (n == ALIGN_NUM);
}
static volatile size_t maskv = 0;
static void
do_one_test (json_ctx_t *json_ctx, impl_t *impl, size_t iters,
uint32_t *input, size_t n)
{
timing_t start, stop, cur;
size_t res = 0;
size_t mask = maskv;
/* Avoid 'cold start' performance penalty. */
for (int i = 0; i < 10; i++)
for (int j = 0; j < n; j++)
CALL (impl, (const char*)buf1 + input[j]);
TIMING_NOW (start);
for (int i = 0; i < iters; ++i)
for (int j = 0; j < n; j++)
res = CALL (impl, (const char*)buf1 + input[j] + (res & mask));
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 n;
uint8_t *a = buf1;
uint16_t index[MAX_ALIGN];
memset (a, 'x', MIN_PAGE_SIZE);
/* Create indices for strings at all alignments. */
for (int i = 0; i < MAX_ALIGN; i++)
{
index[i] = i * (MAX_STRLEN + 1);
a[index[i] + MAX_STRLEN] = 0;
}
/* Create a random set of strlen input strings using the string length
and alignment distributions. */
for (n = 0; n < NUM_TESTS; n++)
{
int align = strlen_align_arr[rand () & ALIGN_MASK];
int exp_len = strlen_len_arr[rand () & SIZE_MASK];
strlen_tests[n] =
index[(align + exp_len) & (MAX_ALIGN - 1)] + MAX_STRLEN - exp_len;
assert ((strlen_tests[n] & (align - 1)) == 0);
assert (strlen ((char*) a + strlen_tests[n]) == exp_len);
}
json_element_object_begin (json_ctx);
json_array_begin (json_ctx, "timings");
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, INNER_LOOP_ITERS_MEDIUM, strlen_tests, n);
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
int
test_main (void)
{
json_ctx_t json_ctx;
test_init ();
init_strlen_distribution ();
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", "random");
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");
do_test (&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>
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