1 /* arc4random benchmarks.
2 Copyright (C) 2022-2023 Free Software Foundation, Inc.
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 <https://www.gnu.org/licenses/>. */
18
19 #include "bench-timing.h"
20 #include "bench-util.h"
21 #include "json-lib.h"
22 #include <array_length.h>
23 #include <intprops.h>
24 #include <signal.h>
25 #include <stdbool.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <support/support.h>
29 #include <support/timespec.h>
30 #include <support/xthread.h>
31
32 static volatile sig_atomic_t timer_finished;
33
34 static void timer_callback (int unused)
35 {
36 timer_finished = 1;
37 }
38
39 static timer_t timer;
40
41 /* Run for approximately DURATION seconds, and it does not matter who
42 receive the signal (so not need to mask it on main thread). */
43 static void
44 timer_start (void)
45 {
46 timer_finished = 0;
47 timer = support_create_timer (DURATION, 0, false, timer_callback);
48 }
49 static void
50 timer_stop (void)
51 {
52 support_delete_timer (timer);
53 }
54
55 static const uint32_t sizes[] = { 0, 16, 32, 48, 64, 80, 96, 112, 128 };
56
57 static double
58 bench_throughput (void)
59 {
60 uint64_t n = 0;
61
62 struct timespec start, end;
63 clock_gettime (CLOCK_MONOTONIC, &start);
64 while (1)
65 {
66 DO_NOT_OPTIMIZE_OUT (arc4random ());
67 n++;
68
69 if (timer_finished == 1)
70 break;
71 }
72 clock_gettime (CLOCK_MONOTONIC, &end);
73 struct timespec diff = timespec_sub (end, start);
74
75 double total = (double) n * sizeof (uint32_t);
76 double duration = (double) diff.tv_sec
77 + (double) diff.tv_nsec / TIMESPEC_HZ;
78
79 return total / duration;
80 }
81
82 static double
83 bench_latency (void)
84 {
85 timing_t start, stop, cur;
86 const size_t iters = 1024;
87
88 TIMING_NOW (start);
89 for (size_t i = 0; i < iters; i++)
90 DO_NOT_OPTIMIZE_OUT (arc4random ());
91 TIMING_NOW (stop);
92
93 TIMING_DIFF (cur, start, stop);
94
95 return (double) (cur) / (double) iters;
96 }
97
98 static double
99 bench_buf_throughput (size_t len)
100 {
101 uint8_t buf[len];
102 uint64_t n = 0;
103
104 struct timespec start, end;
105 clock_gettime (CLOCK_MONOTONIC, &start);
106 while (1)
107 {
108 arc4random_buf (buf, len);
109 n++;
110
111 if (timer_finished == 1)
112 break;
113 }
114 clock_gettime (CLOCK_MONOTONIC, &end);
115 struct timespec diff = timespec_sub (end, start);
116
117 double total = (double) n * len;
118 double duration = (double) diff.tv_sec
119 + (double) diff.tv_nsec / TIMESPEC_HZ;
120
121 return total / duration;
122 }
123
124 static double
125 bench_buf_latency (size_t len)
126 {
127 timing_t start, stop, cur;
128 const size_t iters = 1024;
129
130 uint8_t buf[len];
131
132 TIMING_NOW (start);
133 for (size_t i = 0; i < iters; i++)
134 arc4random_buf (buf, len);
135 TIMING_NOW (stop);
136
137 TIMING_DIFF (cur, start, stop);
138
139 return (double) (cur) / (double) iters;
140 }
141
142 static void
143 bench_singlethread (json_ctx_t *json_ctx)
144 {
145 json_element_object_begin (json_ctx);
146
147 json_array_begin (json_ctx, "throughput");
148 for (int i = 0; i < array_length (sizes); i++)
149 {
150 timer_start ();
151 double r = sizes[i] == 0
152 ? bench_throughput () : bench_buf_throughput (sizes[i]);
153 timer_stop ();
154
155 json_element_double (json_ctx, r);
156 }
157 json_array_end (json_ctx);
158
159 json_array_begin (json_ctx, "latency");
160 for (int i = 0; i < array_length (sizes); i++)
161 {
162 timer_start ();
163 double r = sizes[i] == 0
164 ? bench_latency () : bench_buf_latency (sizes[i]);
165 timer_stop ();
166
167 json_element_double (json_ctx, r);
168 }
169 json_array_end (json_ctx);
170
171 json_element_object_end (json_ctx);
172 }
173
174 static void
175 run_bench (json_ctx_t *json_ctx, const char *name,
176 char *const*fnames, size_t fnameslen,
177 void (*bench) (json_ctx_t *ctx))
178 {
179 json_attr_object_begin (json_ctx, name);
180 json_array_begin (json_ctx, "functions");
181 for (int i = 0; i < fnameslen; i++)
182 json_element_string (json_ctx, fnames[i]);
183 json_array_end (json_ctx);
184
185 json_array_begin (json_ctx, "results");
186 bench (json_ctx);
187 json_array_end (json_ctx);
188 json_attr_object_end (json_ctx);
189 }
190
191 static int
192 do_test (void)
193 {
194 char *fnames[array_length (sizes)];
195 for (int i = 0; i < array_length (sizes); i++)
196 if (sizes[i] == 0)
197 fnames[i] = xasprintf ("arc4random");
198 else
199 fnames[i] = xasprintf ("arc4random_buf(%u)", sizes[i]);
200
201 json_ctx_t json_ctx;
202 json_init (&json_ctx, 0, stdout);
203
204 json_document_begin (&json_ctx);
205 json_attr_string (&json_ctx, "timing_type", TIMING_TYPE);
206
207 run_bench (&json_ctx, "single-thread", fnames, array_length (fnames),
208 bench_singlethread);
209
210 json_document_end (&json_ctx);
211
212 for (int i = 0; i < array_length (sizes); i++)
213 free (fnames[i]);
214
215 return 0;
216 }
217
218 #include <support/test-driver.c>