/* Measure memset performance.
Copyright (C) 2024-2025 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
. */
#define MIN_SIZE 32768
#define MAX_SIZE (1024*1024)
#define NUM_TESTS 16384
#define MIN_PAGE_SIZE (MAX_SIZE + getpagesize())
#define TEST_MAIN
#define TEST_NAME "memset"
#include "bench-string.h"
#include
#include "json-lib.h"
typedef void *(*proto_t) (void *, int, size_t);
IMPL (MEMSET, 1)
typedef struct { uint32_t offset : 20, len : 12; } memset_test_t;
static memset_test_t test_arr[NUM_TESTS];
typedef struct { uint16_t size; uint16_t freq; } freq_data_t;
typedef struct { uint8_t align; uint16_t freq; } align_data_t;
#define SIZE_NUM 65536
#define SIZE_MASK (SIZE_NUM-1)
static uint16_t len_arr[SIZE_NUM];
/* Frequency data for memset sizes up to 4096 bytes based on SPEC2017. */
static freq_data_t memset_len_freq[] =
{
{40,28817}, {32,15336}, { 16,3823}, {296,3545}, { 24,3454}, { 8,1412},
{292,1202}, { 48, 927}, { 12, 613}, { 11, 539}, {284, 493}, {108, 414},
{ 88, 380}, { 20, 295}, {312, 271}, { 72, 233}, { 2, 200}, { 4, 192},
{ 15, 180}, { 14, 174}, { 13, 160}, { 56, 151}, { 36, 144}, { 64, 140},
{4095,133}, { 10, 130}, { 9, 124}, { 3, 124}, { 28, 120}, { 0, 118},
{288, 110}, {1152, 96}, {104, 90}, { 1, 86}, {832, 76}, {248, 74},
{1024, 69}, {120, 64}, {512, 63}, {384, 60}, { 6, 59}, { 80, 54},
{ 17, 50}, { 7, 49}, {520, 47}, {2048, 39}, {256, 37}, {864, 33},
{1440, 28}, { 22, 27}, {2056, 24}, {260, 23}, { 68, 23}, { 5, 22},
{ 18, 21}, {200, 18}, {2120, 18}, { 60, 17}, { 52, 16}, {336, 15},
{ 44, 13}, {192, 13}, {160, 12}, {2064, 12}, {128, 12}, { 76, 11},
{164, 11}, {152, 10}, {136, 9}, {488, 7}, { 96, 6}, {560, 6},
{1016, 6}, {112, 5}, {232, 5}, {168, 5}, {952, 5}, {184, 5},
{144, 4}, {252, 4}, { 84, 3}, {960, 3}, {3808, 3}, {244, 3},
{280, 3}, {224, 3}, {156, 3}, {1088, 3}, {440, 3}, {216, 2},
{304, 2}, { 23, 2}, { 25, 2}, { 26, 2}, {264, 2}, {328, 2},
{1096, 2}, {240, 2}, {1104, 2}, {704, 2}, {1664, 2}, {360, 2},
{808, 1}, {544, 1}, {236, 1}, {720, 1}, {368, 1}, {424, 1},
{640, 1}, {1112, 1}, {552, 1}, {272, 1}, {776, 1}, {376, 1},
{ 92, 1}, {536, 1}, {824, 1}, {496, 1}, {760, 1}, {792, 1},
{504, 1}, {344, 1}, {1816, 1}, {880, 1}, {176, 1}, {320, 1},
{352, 1}, {2008, 1}, {208, 1}, {408, 1}, {228, 1}, {2072, 1},
{568, 1}, {220, 1}, {616, 1}, {600, 1}, {392, 1}, {696, 1},
{2144, 1}, {1280, 1}, {2136, 1}, {632, 1}, {584, 1}, {456, 1},
{472, 1}, {3440, 1}, {2088, 1}, {680, 1}, {2928, 1}, {212, 1},
{648, 1}, {1752, 1}, {664, 1}, {3512, 1}, {1032, 1}, {528, 1},
{4072, 1}, {204, 1}, {2880, 1}, {3392, 1}, {712, 1}, { 59, 1},
{736, 1}, {592, 1}, {2520, 1}, {744, 1}, {196, 1}, {172, 1},
{728, 1}, {2040, 1}, {1192, 1}, {3600, 1}, {0, 0}
};
#define ALIGN_NUM 1024
#define ALIGN_MASK (ALIGN_NUM-1)
static uint8_t align_arr[ALIGN_NUM];
/* Alignment data for memset based on SPEC2017. */
static align_data_t memset_align_freq[] =
{
{16, 338}, {8, 307}, {32, 148}, {64, 131}, {4, 72}, {1, 23}, {2, 5}, {0, 0}
};
static void
init_memset_distribution (void)
{
int i, j, freq, size, n;
for (n = i = 0; (freq = memset_len_freq[i].freq) != 0; i++)
for (j = 0, size = memset_len_freq[i].size; j < freq; j++)
len_arr[n++] = size;
assert (n == SIZE_NUM);
for (n = i = 0; (freq = memset_align_freq[i].freq) != 0; i++)
for (j = 0, size = memset_align_freq[i].align; j < freq; j++)
align_arr[n++] = size - 1;
assert (n == ALIGN_NUM);
}
static void
do_one_test (json_ctx_t *json_ctx, impl_t *impl, size_t iters,
memset_test_t *input, size_t n)
{
timing_t start, stop, cur;
/* Avoid 'cold start' performance penalty. */
for (int j = 0; j < n; j++)
CALL (impl, buf1 + input[j].offset, 0, input[j].len);
TIMING_NOW (start);
for (int i = 0; i < iters; ++i)
for (int j = 0; j < n; j++)
CALL (impl, buf1 + input[j].offset, 0, input[j].len);
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 max_size)
{
int n;
/* Create a random set of memset inputs strings with the given length
and alignment distributions. */
for (n = 0; n < NUM_TESTS; n++)
{
int align = align_arr[rand () & ALIGN_MASK];
int len = len_arr[rand () & SIZE_MASK];
test_arr[n].offset = (rand () & (max_size - 1)) & ~align;
test_arr[n].len = len;
}
json_element_object_begin (json_ctx);
json_attr_uint (json_ctx, "length", (double) max_size);
json_array_begin (json_ctx, "timings");
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, INNER_LOOP_ITERS_MEDIUM * 2, test_arr, n);
json_array_end (json_ctx);
json_element_object_end (json_ctx);
}
int
test_main (void)
{
json_ctx_t json_ctx;
test_init ();
init_memset_distribution ();
memset (buf1, 1, MIN_PAGE_SIZE);
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");
for (int i = MIN_SIZE; i <= MAX_SIZE; i = i * 2)
do_test (&json_ctx, i);
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