1 /* Measure lock functions for different threads and critical sections.
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 #define TEST_MAIN
20 #define TIMEOUT (20 * 60)
21
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <unistd.h>
26 #include <math.h>
27 #include <pthread.h>
28 #include <sys/time.h>
29 #include <sys/sysinfo.h>
30 #include "bench-timing.h"
31 #include "json-lib.h"
32
33 static bench_lock_t lock;
34 static bench_lock_attr_t attr;
35 static pthread_barrier_t barrier;
36
37 #define START_ITERS 1000
38
39 #pragma GCC push_options
40 #pragma GCC optimize(1)
41
42 static int __attribute__ ((noinline)) fibonacci (int i)
43 {
44 asm("");
45 if (i > 2)
46 return fibonacci (i - 1) + fibonacci (i - 2);
47 return 10 + i;
48 }
49
50 static void
51 do_filler (void)
52 {
53 char buf1[512], buf2[512];
54 int f = fibonacci (4);
55 memcpy (buf1, buf2, f);
56 }
57
58 static void
59 do_filler_shared (void)
60 {
61 static char buf1[512], buf2[512];
62 int f = fibonacci (4);
63 memcpy (buf1, buf2, f);
64 }
65
66 #pragma GCC pop_options
67
68 #define UNIT_WORK_CRT do_filler_shared ()
69 #define UNIT_WORK_NON_CRT do_filler ()
70
71 static inline void
72 critical_section (int length)
73 {
74 for (int i = length; i >= 0; i--)
75 UNIT_WORK_CRT;
76 }
77
78 static inline void
79 non_critical_section (int length)
80 {
81 for (int i = length; i >= 0; i--)
82 UNIT_WORK_NON_CRT;
83 }
84
85 typedef struct Worker_Params
86 {
87 long iters;
88 int crt_len;
89 int non_crt_len;
90 timing_t duration;
91 } Worker_Params;
92
93 static void *
94 worker (void *v)
95 {
96 timing_t start, stop;
97 Worker_Params *p = (Worker_Params *) v;
98 long iters = p->iters;
99 int crt_len = p->crt_len;
100 int non_crt_len = p->non_crt_len;
101
102 pthread_barrier_wait (&barrier);
103 TIMING_NOW (start);
104 while (iters--)
105 {
106 LOCK (&lock);
107 critical_section (crt_len);
108 UNLOCK (&lock);
109 non_critical_section (non_crt_len);
110 }
111 TIMING_NOW (stop);
112
113 TIMING_DIFF (p->duration, start, stop);
114 return NULL;
115 }
116
117 static double
118 do_one_test (int num_threads, int crt_len, int non_crt_len, long iters)
119 {
120 int i;
121 timing_t mean;
122 Worker_Params *p, params[num_threads];
123 pthread_t threads[num_threads];
124
125 LOCK_INIT (&lock, &attr);
126 pthread_barrier_init (&barrier, NULL, num_threads);
127
128 for (i = 0; i < num_threads; i++)
129 {
130 p = ¶ms[i];
131 p->iters = iters;
132 p->crt_len = crt_len;
133 p->non_crt_len = non_crt_len;
134 pthread_create (&threads[i], NULL, worker, (void *) p);
135 }
136 for (i = 0; i < num_threads; i++)
137 pthread_join (threads[i], NULL);
138
139 LOCK_DESTROY (&lock);
140 pthread_barrier_destroy (&barrier);
141
142 mean = 0;
143 for (i = 0; i < num_threads; i++)
144 mean += params[i].duration;
145 mean /= num_threads;
146 return mean;
147 }
148
149 #define RUN_COUNT 10
150 #define MIN_TEST_SEC 0.01
151
152 static void
153 do_bench_one (const char *name, int num_threads, int crt_len, int non_crt_len,
154 json_ctx_t *js)
155 {
156 timing_t cur;
157 struct timeval ts, te;
158 double tsd, ted, td;
159 long iters, iters_limit, total_iters;
160 timing_t curs[RUN_COUNT + 2];
161 int i, j;
162 double mean, stdev;
163
164 iters = START_ITERS;
165 iters_limit = LONG_MAX / 100;
166
167 while (1)
168 {
169 gettimeofday (&ts, NULL);
170 cur = do_one_test (num_threads, crt_len, non_crt_len, iters);
171 gettimeofday (&te, NULL);
172 /* Make sure the test to run at least MIN_TEST_SEC. */
173 tsd = ts.tv_sec + ts.tv_usec / 1000000.0;
174 ted = te.tv_sec + te.tv_usec / 1000000.0;
175 td = ted - tsd;
176 if (td >= MIN_TEST_SEC || iters >= iters_limit)
177 break;
178
179 iters *= 10;
180 }
181
182 curs[0] = cur;
183 for (i = 1; i < RUN_COUNT + 2; i++)
184 curs[i] = do_one_test (num_threads, crt_len, non_crt_len, iters);
185
186 /* Sort the results so we can discard the fastest and slowest
187 times as outliers. */
188 for (i = 0; i < RUN_COUNT + 1; i++)
189 for (j = i + 1; j < RUN_COUNT + 2; j++)
190 if (curs[i] > curs[j])
191 {
192 timing_t temp = curs[i];
193 curs[i] = curs[j];
194 curs[j] = temp;
195 }
196
197 /* Calculate mean and standard deviation. */
198 mean = 0.0;
199 total_iters = iters * num_threads;
200 for (i = 1; i < RUN_COUNT + 1; i++)
201 mean += (double) curs[i] / (double) total_iters;
202 mean /= RUN_COUNT;
203
204 stdev = 0.0;
205 for (i = 1; i < RUN_COUNT + 1; i++)
206 {
207 double s = (double) curs[i] / (double) total_iters - mean;
208 stdev += s * s;
209 }
210 stdev = sqrt (stdev / (RUN_COUNT - 1));
211
212 char buf[256];
213 snprintf (buf, sizeof buf, "%s,non_crt_len=%d,crt_len=%d,threads=%d", name,
214 non_crt_len, crt_len, num_threads);
215
216 json_attr_object_begin (js, buf);
217
218 json_attr_double (js, "duration", (double) cur);
219 json_attr_double (js, "iterations", (double) total_iters);
220 json_attr_double (js, "mean", mean);
221 json_attr_double (js, "stdev", stdev);
222 json_attr_double (js, "min-outlier",
223 (double) curs[0] / (double) total_iters);
224 json_attr_double (js, "min", (double) curs[1] / (double) total_iters);
225 json_attr_double (js, "max",
226 (double) curs[RUN_COUNT] / (double) total_iters);
227 json_attr_double (js, "max-outlier",
228 (double) curs[RUN_COUNT + 1] / (double) total_iters);
229
230 json_attr_object_end (js);
231 }
232
233 #define TH_CONF_MAX 10
234
235 int
236 do_bench (void)
237 {
238 int rv = 0;
239 json_ctx_t json_ctx;
240 int i, j, k;
241 int th_num, th_conf, nprocs;
242 int threads[TH_CONF_MAX];
243 int crt_lens[] = { 0, 1, 2, 4, 8, 16, 32, 64, 128 };
244 int non_crt_lens[] = { 1, 32, 128 };
245 char name[128];
246
247 json_init (&json_ctx, 2, stdout);
248 json_attr_object_begin (&json_ctx, TEST_NAME);
249
250 /* The thread config begins from 1, and increases by 2x until nprocs.
251 We also wants to test over-saturation case (1.25*nprocs). */
252 nprocs = get_nprocs ();
253 th_num = 1;
254 for (th_conf = 0; th_conf < (TH_CONF_MAX - 2) && th_num < nprocs; th_conf++)
255 {
256 threads[th_conf] = th_num;
257 th_num <<= 1;
258 }
259 threads[th_conf++] = nprocs;
260 threads[th_conf++] = nprocs + nprocs / 4;
261
262 LOCK_ATTR_INIT (&attr);
263 snprintf (name, sizeof name, "type=adaptive");
264
265 for (k = 0; k < (sizeof (non_crt_lens) / sizeof (int)); k++)
266 {
267 int non_crt_len = non_crt_lens[k];
268 for (j = 0; j < (sizeof (crt_lens) / sizeof (int)); j++)
269 {
270 int crt_len = crt_lens[j];
271 for (i = 0; i < th_conf; i++)
272 {
273 th_num = threads[i];
274 do_bench_one (name, th_num, crt_len, non_crt_len, &json_ctx);
275 }
276 }
277 }
278
279 json_attr_object_end (&json_ctx);
280
281 return rv;
282 }
283
284 #define TEST_FUNCTION do_bench ()
285
286 #include "../test-skeleton.c"