| /* Measure memmove function combined throughput for different alignments. |
| Copyright (C) 2017-2018 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 |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* This microbenchmark measures the throughput of memmove for various sizes from |
| 1 byte to 32MiB, doubling every iteration and then misaligning by 0-15 |
| bytes. The copies are done from source to destination and then back and the |
| source walks forward across the array and the destination walks backward by |
| one byte each, thus measuring misaligned accesses as well. The idea is to |
| avoid caching effects by copying a different string and far enough from each |
| other, walking in different directions so that we can measure prefetcher |
| efficiency (software or hardware) more closely than with a loop copying the |
| same data over and over, which eventually only gives us L1 cache |
| performance. */ |
| |
| #ifndef MEMMOVE_RESULT |
| # define MEMMOVE_RESULT(dst, len) dst |
| # define START_SIZE 128 |
| # define MIN_PAGE_SIZE (getpagesize () + 32 * 1024 * 1024) |
| # define TEST_MAIN |
| # define TEST_NAME "memmove" |
| # define TIMEOUT (20 * 60) |
| # include "bench-string.h" |
| |
| IMPL (memmove, 1) |
| #endif |
| |
| #include "json-lib.h" |
| |
| typedef char *(*proto_t) (char *, const char *, size_t); |
| |
| static void |
| do_one_test (json_ctx_t *json_ctx, impl_t *impl, char *dst, char *src, |
| size_t len) |
| { |
| size_t i = 0; |
| timing_t start, stop, cur; |
| |
| char *dst_end = dst + MIN_PAGE_SIZE - len; |
| char *src_end = src + MIN_PAGE_SIZE - len; |
| |
| TIMING_NOW (start); |
| /* Copy the entire buffer backwards, LEN at a time. */ |
| for (; src_end >= src && dst <= dst_end; dst += len, src_end -= len, i++) |
| CALL (impl, dst, src_end, len); |
| TIMING_NOW (stop); |
| |
| TIMING_DIFF (cur, start, stop); |
| |
| /* Get time taken per function call. */ |
| json_element_double (json_ctx, (double) cur / i); |
| } |
| |
| static void |
| do_test (json_ctx_t *json_ctx, size_t len, bool overlap) |
| { |
| json_element_object_begin (json_ctx); |
| json_attr_uint (json_ctx, "length", (double) len); |
| json_array_begin (json_ctx, "timings"); |
| |
| if (overlap) |
| buf2 = buf1; |
| |
| FOR_EACH_IMPL (impl, 0) |
| do_one_test (json_ctx, impl, (char *) buf2, (char *) buf1, len); |
| |
| json_array_end (json_ctx); |
| json_element_object_end (json_ctx); |
| } |
| |
| int |
| test_main (void) |
| { |
| json_ctx_t json_ctx; |
| size_t i; |
| |
| 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, "memmove"); |
| json_attr_string (&json_ctx, "bench-variant", "walk"); |
| |
| 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"); |
| /* Non-overlapping buffers. */ |
| for (i = START_SIZE; i <= MIN_PAGE_SIZE; i <<= 1) |
| { |
| /* Test length alignments from 0-16 bytes. */ |
| for (int j = 0; j < 8; j++) |
| { |
| do_test (&json_ctx, i + j, false); |
| do_test (&json_ctx, i + 16 - j, false); |
| } |
| } |
| |
| /* Overlapping buffers. */ |
| for (i = START_SIZE; i <= MIN_PAGE_SIZE; i <<= 1) |
| { |
| /* Test length alignments from 0-16 bytes. */ |
| for (int j = 0; j < 8; j++) |
| { |
| do_test (&json_ctx, i + j, true); |
| do_test (&json_ctx, i + 16 - j, true); |
| } |
| } |
| |
| 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> |