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9ec87fd2 | 1 | /* Measure memcpy function combined throughput for different alignments. |
04277e02 | 2 | Copyright (C) 2017-2019 Free Software Foundation, Inc. |
9ec87fd2 SP |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | /* This microbenchmark measures the throughput of memcpy for various sizes from | |
20 | 1 byte to 32MiB, doubling every iteration and then misaligning by 0-15 | |
21 | bytes. The copies are done from source to destination and then back and the | |
22 | source walks forward across the array and the destination walks backward by | |
23 | one byte each, thus measuring misaligned accesses as well. The idea is to | |
24 | avoid caching effects by copying a different string and far enough from each | |
25 | other, walking in different directions so that we can measure prefetcher | |
26 | efficiency (software or hardware) more closely than with a loop copying the | |
27 | same data over and over, which eventually only gives us L1 cache | |
28 | performance. */ | |
29 | ||
30 | #ifndef MEMCPY_RESULT | |
31 | # define MEMCPY_RESULT(dst, len) dst | |
eb332f9f | 32 | # define START_SIZE 128 |
9ec87fd2 SP |
33 | # define MIN_PAGE_SIZE (getpagesize () + 32 * 1024 * 1024) |
34 | # define TEST_MAIN | |
35 | # define TEST_NAME "memcpy" | |
36 | # define TIMEOUT (20 * 60) | |
37 | # include "bench-string.h" | |
38 | ||
39 | IMPL (memcpy, 1) | |
40 | #endif | |
41 | ||
42 | #include "json-lib.h" | |
43 | ||
44 | typedef char *(*proto_t) (char *, const char *, size_t); | |
45 | ||
46 | static void | |
47 | do_one_test (json_ctx_t *json_ctx, impl_t *impl, char *dst, char *src, | |
48 | size_t len) | |
49 | { | |
4d7632ff | 50 | size_t i = 0; |
9ec87fd2 SP |
51 | timing_t start, stop, cur; |
52 | ||
53 | char *dst_end = dst + MIN_PAGE_SIZE - len; | |
54 | char *src_end = src + MIN_PAGE_SIZE - len; | |
55 | ||
56 | TIMING_NOW (start); | |
4d7632ff SP |
57 | /* Copy the entire buffer backwards, LEN at a time. */ |
58 | for (; src_end >= src && dst_end >= dst; src_end -= len, dst_end -= len, i++) | |
59 | CALL (impl, src_end, dst_end, len); | |
9ec87fd2 SP |
60 | TIMING_NOW (stop); |
61 | ||
62 | TIMING_DIFF (cur, start, stop); | |
63 | ||
64 | /* Get time taken per function call. */ | |
4d7632ff | 65 | json_element_double (json_ctx, (double) cur / i); |
9ec87fd2 SP |
66 | } |
67 | ||
68 | static void | |
69 | do_test (json_ctx_t *json_ctx, size_t len) | |
70 | { | |
71 | json_element_object_begin (json_ctx); | |
72 | json_attr_uint (json_ctx, "length", (double) len); | |
73 | json_array_begin (json_ctx, "timings"); | |
74 | ||
75 | FOR_EACH_IMPL (impl, 0) | |
76 | do_one_test (json_ctx, impl, (char *) buf2, (char *) buf1, len); | |
77 | ||
78 | json_array_end (json_ctx); | |
79 | json_element_object_end (json_ctx); | |
80 | } | |
81 | ||
82 | int | |
83 | test_main (void) | |
84 | { | |
85 | json_ctx_t json_ctx; | |
9ec87fd2 SP |
86 | |
87 | test_init (); | |
88 | ||
89 | json_init (&json_ctx, 0, stdout); | |
90 | ||
91 | json_document_begin (&json_ctx); | |
92 | json_attr_string (&json_ctx, "timing_type", TIMING_TYPE); | |
93 | ||
94 | json_attr_object_begin (&json_ctx, "functions"); | |
95 | json_attr_object_begin (&json_ctx, "memcpy"); | |
96 | json_attr_string (&json_ctx, "bench-variant", "walk"); | |
97 | ||
98 | json_array_begin (&json_ctx, "ifuncs"); | |
99 | FOR_EACH_IMPL (impl, 0) | |
100 | json_element_string (&json_ctx, impl->name); | |
101 | json_array_end (&json_ctx); | |
102 | ||
103 | json_array_begin (&json_ctx, "results"); | |
543477f7 | 104 | for (size_t i = START_SIZE; i <= MIN_PAGE_SIZE; i <<= 1) |
9ec87fd2 SP |
105 | { |
106 | /* Test length alignments from 0-16 bytes. */ | |
107 | for (int j = 0; j < 8; j++) | |
108 | { | |
109 | do_test (&json_ctx, i + j); | |
110 | do_test (&json_ctx, i + 16 - j); | |
111 | } | |
112 | } | |
113 | ||
114 | json_array_end (&json_ctx); | |
115 | json_attr_object_end (&json_ctx); | |
116 | json_attr_object_end (&json_ctx); | |
117 | json_document_end (&json_ctx); | |
118 | ||
119 | return ret; | |
120 | } | |
121 | ||
122 | #include <support/test-driver.c> |