2 * rcutorture.c: simple user-level performance/stress test of RCU.
5 * ./rcu <nreaders> rperf [ <seconds> ]
6 * Run a read-side performance test with the specified
7 * number of readers for <seconds> seconds.
8 * ./rcu <nupdaters> uperf [ <seconds> ]
9 * Run an update-side performance test with the specified
10 * number of updaters and specified duration.
11 * ./rcu <nreaders> perf [ <seconds> ]
12 * Run a combined read/update performance test with the specified
13 * number of readers and one updater and specified duration.
15 * The above tests produce output as follows:
17 * n_reads: 46008000 n_updates: 146026 nreaders: 2 nupdaters: 1 duration: 1
18 * ns/read: 43.4707 ns/update: 6848.1
20 * The first line lists the total number of RCU reads and updates executed
21 * during the test, the number of reader threads, the number of updater
22 * threads, and the duration of the test in seconds. The second line
23 * lists the average duration of each type of operation in nanoseconds,
24 * or "nan" if the corresponding type of operation was not performed.
26 * ./rcu <nreaders> stress [ <seconds> ]
27 * Run a stress test with the specified number of readers and
30 * This test produces output as follows:
32 * n_reads: 114633217 n_updates: 3903415 n_mberror: 0
33 * rcu_stress_count: 114618391 14826 0 0 0 0 0 0 0 0 0
35 * The first line lists the number of RCU read and update operations
36 * executed, followed by the number of memory-ordering violations
37 * (which will be zero in a correct RCU implementation). The second
38 * line lists the number of readers observing progressively more stale
39 * data. A correct RCU implementation will have all but the first two
42 * This program is free software; you can redistribute it and/or modify
43 * it under the terms of the GNU General Public License as published by
44 * the Free Software Foundation; either version 2 of the License, or
45 * (at your option) any later version.
47 * This program is distributed in the hope that it will be useful,
48 * but WITHOUT ANY WARRANTY; without even the implied warranty of
49 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
50 * GNU General Public License for more details.
52 * You should have received a copy of the GNU General Public License
53 * along with this program; if not, write to the Free Software
54 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
56 * Copyright (c) 2008 Paul E. McKenney, IBM Corporation.
67 #include "qemu/atomic.h"
69 #include "qemu/compiler.h"
70 #include "qemu/thread.h"
72 long long n_reads = 0LL;
80 static volatile int goflag = GOFLAG_INIT;
82 #define RCU_READ_RUN 1000
84 #define NR_THREADS 100
85 static QemuMutex counts_mutex;
86 static QemuThread threads[NR_THREADS];
87 static struct rcu_reader_data *data[NR_THREADS];
90 static void create_thread(void *(*func)(void *))
92 if (n_threads >= NR_THREADS) {
93 fprintf(stderr, "Thread limit of %d exceeded!\n", NR_THREADS);
96 qemu_thread_create(&threads[n_threads], "test", func, &data[n_threads],
97 QEMU_THREAD_JOINABLE);
101 static void wait_all_threads(void)
105 for (i = 0; i < n_threads; i++) {
106 qemu_thread_join(&threads[i]);
115 static void *rcu_read_perf_test(void *arg)
118 long long n_reads_local = 0;
120 rcu_register_thread();
122 *(struct rcu_reader_data **)arg = &rcu_reader;
123 atomic_inc(&nthreadsrunning);
124 while (goflag == GOFLAG_INIT) {
127 while (goflag == GOFLAG_RUN) {
128 for (i = 0; i < RCU_READ_RUN; i++) {
132 n_reads_local += RCU_READ_RUN;
134 qemu_mutex_lock(&counts_mutex);
135 n_reads += n_reads_local;
136 qemu_mutex_unlock(&counts_mutex);
138 rcu_unregister_thread();
142 static void *rcu_update_perf_test(void *arg)
144 long long n_updates_local = 0;
146 rcu_register_thread();
148 *(struct rcu_reader_data **)arg = &rcu_reader;
149 atomic_inc(&nthreadsrunning);
150 while (goflag == GOFLAG_INIT) {
153 while (goflag == GOFLAG_RUN) {
157 qemu_mutex_lock(&counts_mutex);
158 n_updates += n_updates_local;
159 qemu_mutex_unlock(&counts_mutex);
161 rcu_unregister_thread();
165 static void perftestinit(void)
170 static void perftestrun(int nthreads, int duration, int nreaders, int nupdaters)
172 while (atomic_read(&nthreadsrunning) < nthreads) {
176 g_usleep(duration * G_USEC_PER_SEC);
177 goflag = GOFLAG_STOP;
179 printf("n_reads: %lld n_updates: %ld nreaders: %d nupdaters: %d duration: %d\n",
180 n_reads, n_updates, nreaders, nupdaters, duration);
181 printf("ns/read: %g ns/update: %g\n",
182 ((duration * 1000*1000*1000.*(double)nreaders) /
184 ((duration * 1000*1000*1000.*(double)nupdaters) /
189 static void perftest(int nreaders, int duration)
194 for (i = 0; i < nreaders; i++) {
195 create_thread(rcu_read_perf_test);
197 create_thread(rcu_update_perf_test);
198 perftestrun(i + 1, duration, nreaders, 1);
201 static void rperftest(int nreaders, int duration)
206 for (i = 0; i < nreaders; i++) {
207 create_thread(rcu_read_perf_test);
209 perftestrun(i, duration, nreaders, 0);
212 static void uperftest(int nupdaters, int duration)
217 for (i = 0; i < nupdaters; i++) {
218 create_thread(rcu_update_perf_test);
220 perftestrun(i, duration, 0, nupdaters);
227 #define RCU_STRESS_PIPE_LEN 10
234 struct rcu_stress rcu_stress_array[RCU_STRESS_PIPE_LEN] = { { 0 } };
235 struct rcu_stress *rcu_stress_current;
239 long long rcu_stress_count[RCU_STRESS_PIPE_LEN + 1];
242 static void *rcu_read_stress_test(void *arg)
246 struct rcu_stress *p;
248 long long n_reads_local = 0;
249 long long rcu_stress_local[RCU_STRESS_PIPE_LEN + 1] = { 0 };
250 volatile int garbage = 0;
252 rcu_register_thread();
254 *(struct rcu_reader_data **)arg = &rcu_reader;
255 while (goflag == GOFLAG_INIT) {
258 while (goflag == GOFLAG_RUN) {
260 p = atomic_rcu_read(&rcu_stress_current);
261 if (p->mbtest == 0) {
265 for (i = 0; i < 100; i++) {
271 if ((pc > RCU_STRESS_PIPE_LEN) || (pc < 0)) {
272 pc = RCU_STRESS_PIPE_LEN;
274 rcu_stress_local[pc]++;
276 if ((++itercnt % 0x1000) == 0) {
280 qemu_mutex_lock(&counts_mutex);
281 n_reads += n_reads_local;
282 for (i = 0; i <= RCU_STRESS_PIPE_LEN; i++) {
283 rcu_stress_count[i] += rcu_stress_local[i];
285 qemu_mutex_unlock(&counts_mutex);
287 rcu_unregister_thread();
291 static void *rcu_update_stress_test(void *arg)
294 struct rcu_stress *p;
296 rcu_register_thread();
298 *(struct rcu_reader_data **)arg = &rcu_reader;
299 while (goflag == GOFLAG_INIT) {
302 while (goflag == GOFLAG_RUN) {
303 i = rcu_stress_idx + 1;
304 if (i >= RCU_STRESS_PIPE_LEN) {
307 p = &rcu_stress_array[i];
312 atomic_rcu_set(&rcu_stress_current, p);
314 for (i = 0; i < RCU_STRESS_PIPE_LEN; i++) {
315 if (i != rcu_stress_idx) {
316 rcu_stress_array[i].pipe_count++;
323 rcu_unregister_thread();
327 static void *rcu_fake_update_stress_test(void *arg)
329 rcu_register_thread();
331 *(struct rcu_reader_data **)arg = &rcu_reader;
332 while (goflag == GOFLAG_INIT) {
335 while (goflag == GOFLAG_RUN) {
340 rcu_unregister_thread();
344 static void stresstest(int nreaders, int duration)
348 rcu_stress_current = &rcu_stress_array[0];
349 rcu_stress_current->pipe_count = 0;
350 rcu_stress_current->mbtest = 1;
351 for (i = 0; i < nreaders; i++) {
352 create_thread(rcu_read_stress_test);
354 create_thread(rcu_update_stress_test);
355 for (i = 0; i < 5; i++) {
356 create_thread(rcu_fake_update_stress_test);
359 g_usleep(duration * G_USEC_PER_SEC);
360 goflag = GOFLAG_STOP;
362 printf("n_reads: %lld n_updates: %ld n_mberror: %d\n",
363 n_reads, n_updates, n_mberror);
364 printf("rcu_stress_count:");
365 for (i = 0; i <= RCU_STRESS_PIPE_LEN; i++) {
366 printf(" %lld", rcu_stress_count[i]);
372 /* GTest interface */
374 static void gtest_stress(int nreaders, int duration)
378 rcu_stress_current = &rcu_stress_array[0];
379 rcu_stress_current->pipe_count = 0;
380 rcu_stress_current->mbtest = 1;
381 for (i = 0; i < nreaders; i++) {
382 create_thread(rcu_read_stress_test);
384 create_thread(rcu_update_stress_test);
385 for (i = 0; i < 5; i++) {
386 create_thread(rcu_fake_update_stress_test);
389 g_usleep(duration * G_USEC_PER_SEC);
390 goflag = GOFLAG_STOP;
392 g_assert_cmpint(n_mberror, ==, 0);
393 for (i = 2; i <= RCU_STRESS_PIPE_LEN; i++) {
394 g_assert_cmpint(rcu_stress_count[i], ==, 0);
398 static void gtest_stress_1_1(void)
403 static void gtest_stress_10_1(void)
408 static void gtest_stress_1_5(void)
413 static void gtest_stress_10_5(void)
422 static void usage(int argc, char *argv[])
424 fprintf(stderr, "Usage: %s [nreaders [ perf | stress ] ]\n", argv[0]);
428 int main(int argc, char *argv[])
433 qemu_mutex_init(&counts_mutex);
434 if (argc >= 2 && argv[1][0] == '-') {
435 g_test_init(&argc, &argv, NULL);
436 if (g_test_quick()) {
437 g_test_add_func("/rcu/torture/1reader", gtest_stress_1_1);
438 g_test_add_func("/rcu/torture/10readers", gtest_stress_10_1);
440 g_test_add_func("/rcu/torture/1reader", gtest_stress_1_5);
441 g_test_add_func("/rcu/torture/10readers", gtest_stress_10_5);
447 nreaders = strtoul(argv[1], NULL, 0);
450 duration = strtoul(argv[3], NULL, 0);
452 if (argc < 3 || strcmp(argv[2], "stress") == 0) {
453 stresstest(nreaders, duration);
454 } else if (strcmp(argv[2], "rperf") == 0) {
455 rperftest(nreaders, duration);
456 } else if (strcmp(argv[2], "uperf") == 0) {
457 uperftest(nreaders, duration);
458 } else if (strcmp(argv[2], "perf") == 0) {
459 perftest(nreaders, duration);