tests/rcutorture.c

   1 /*
   2  * rcutorture.c: simple user-level performance/stress test of RCU.
   3  *
   4  * Usage:
   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.
  14  *
  15  * The above tests produce output as follows:
  16  *
  17  * n_reads: 46008000  n_updates: 146026  nreaders: 2  nupdaters: 1 duration: 1
  18  * ns/read: 43.4707  ns/update: 6848.1
  19  *
  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.
  25  *
  26  *     ./rcu <nreaders> stress [ <seconds> ]
  27  *         Run a stress test with the specified number of readers and
  28  *         one updater.
  29  *
  30  * This test produces output as follows:
  31  *
  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
  34  *
  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
  40  * numbers non-zero.
  41  *
  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.
  46  *
  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.
  51  *
  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.
  55  *
  56  * Copyright (c) 2008 Paul E. McKenney, IBM Corporation.
  57  */
  58
  59 /*
  60  * Test variables.
  61  */
  62
  63 #include "qemu/osdep.h"
  64 #include <glib.h>
  65 #include "qemu/atomic.h"
  66 #include "qemu/rcu.h"
  67 #include "qemu/thread.h"
  68
  69 long long n_reads = 0LL;
  70 long n_updates = 0L;
  71 int nthreadsrunning;
  72
  73 #define GOFLAG_INIT 0
  74 #define GOFLAG_RUN  1
  75 #define GOFLAG_STOP 2
  76
  77 static volatile int goflag = GOFLAG_INIT;
  78
  79 #define RCU_READ_RUN 1000
  80
  81 #define NR_THREADS 100
  82 static QemuMutex counts_mutex;
  83 static QemuThread threads[NR_THREADS];
  84 static struct rcu_reader_data *data[NR_THREADS];
  85 static int n_threads;
  86
  87 static void create_thread(void *(*func)(void *))
  88 {
  89     if (n_threads >= NR_THREADS) {
  90         fprintf(stderr, "Thread limit of %d exceeded!\n", NR_THREADS);
  91         exit(-1);
  92     }
  93     qemu_thread_create(&threads[n_threads], "test", func, &data[n_threads],
  94                        QEMU_THREAD_JOINABLE);
  95     n_threads++;
  96 }
  97
  98 static void wait_all_threads(void)
  99 {
 100     int i;
 101
 102     for (i = 0; i < n_threads; i++) {
 103         qemu_thread_join(&threads[i]);
 104     }
 105     n_threads = 0;
 106 }
 107
 108 /*
 109  * Performance test.
 110  */
 111
 112 static void *rcu_read_perf_test(void *arg)
 113 {
 114     int i;
 115     long long n_reads_local = 0;
 116
 117     rcu_register_thread();
 118
 119     *(struct rcu_reader_data **)arg = &rcu_reader;
 120     atomic_inc(&nthreadsrunning);
 121     while (goflag == GOFLAG_INIT) {
 122         g_usleep(1000);
 123     }
 124     while (goflag == GOFLAG_RUN) {
 125         for (i = 0; i < RCU_READ_RUN; i++) {
 126             rcu_read_lock();
 127             rcu_read_unlock();
 128         }
 129         n_reads_local += RCU_READ_RUN;
 130     }
 131     qemu_mutex_lock(&counts_mutex);
 132     n_reads += n_reads_local;
 133     qemu_mutex_unlock(&counts_mutex);
 134
 135     rcu_unregister_thread();
 136     return NULL;
 137 }
 138
 139 static void *rcu_update_perf_test(void *arg)
 140 {
 141     long long n_updates_local = 0;
 142
 143     rcu_register_thread();
 144
 145     *(struct rcu_reader_data **)arg = &rcu_reader;
 146     atomic_inc(&nthreadsrunning);
 147     while (goflag == GOFLAG_INIT) {
 148         g_usleep(1000);
 149     }
 150     while (goflag == GOFLAG_RUN) {
 151         synchronize_rcu();
 152         n_updates_local++;
 153     }
 154     qemu_mutex_lock(&counts_mutex);
 155     n_updates += n_updates_local;
 156     qemu_mutex_unlock(&counts_mutex);
 157
 158     rcu_unregister_thread();
 159     return NULL;
 160 }
 161
 162 static void perftestinit(void)
 163 {
 164     nthreadsrunning = 0;
 165 }
 166
 167 static void perftestrun(int nthreads, int duration, int nreaders, int nupdaters)
 168 {
 169     while (atomic_read(&nthreadsrunning) < nthreads) {
 170         g_usleep(1000);
 171     }
 172     goflag = GOFLAG_RUN;
 173     g_usleep(duration * G_USEC_PER_SEC);
 174     goflag = GOFLAG_STOP;
 175     wait_all_threads();
 176     printf("n_reads: %lld  n_updates: %ld  nreaders: %d  nupdaters: %d duration: %d\n",
 177            n_reads, n_updates, nreaders, nupdaters, duration);
 178     printf("ns/read: %g  ns/update: %g\n",
 179            ((duration * 1000*1000*1000.*(double)nreaders) /
 180         (double)n_reads),
 181            ((duration * 1000*1000*1000.*(double)nupdaters) /
 182         (double)n_updates));
 183     exit(0);
 184 }
 185
 186 static void perftest(int nreaders, int duration)
 187 {
 188     int i;
 189
 190     perftestinit();
 191     for (i = 0; i < nreaders; i++) {
 192         create_thread(rcu_read_perf_test);
 193     }
 194     create_thread(rcu_update_perf_test);
 195     perftestrun(i + 1, duration, nreaders, 1);
 196 }
 197
 198 static void rperftest(int nreaders, int duration)
 199 {
 200     int i;
 201
 202     perftestinit();
 203     for (i = 0; i < nreaders; i++) {
 204         create_thread(rcu_read_perf_test);
 205     }
 206     perftestrun(i, duration, nreaders, 0);
 207 }
 208
 209 static void uperftest(int nupdaters, int duration)
 210 {
 211     int i;
 212
 213     perftestinit();
 214     for (i = 0; i < nupdaters; i++) {
 215         create_thread(rcu_update_perf_test);
 216     }
 217     perftestrun(i, duration, 0, nupdaters);
 218 }
 219
 220 /*
 221  * Stress test.
 222  */
 223
 224 #define RCU_STRESS_PIPE_LEN 10
 225
 226 struct rcu_stress {
 227     int pipe_count;
 228     int mbtest;
 229 };
 230
 231 struct rcu_stress rcu_stress_array[RCU_STRESS_PIPE_LEN] = { { 0 } };
 232 struct rcu_stress *rcu_stress_current;
 233 int rcu_stress_idx;
 234
 235 int n_mberror;
 236 long long rcu_stress_count[RCU_STRESS_PIPE_LEN + 1];
 237
 238
 239 static void *rcu_read_stress_test(void *arg)
 240 {
 241     int i;
 242     int itercnt = 0;
 243     struct rcu_stress *p;
 244     int pc;
 245     long long n_reads_local = 0;
 246     long long rcu_stress_local[RCU_STRESS_PIPE_LEN + 1] = { 0 };
 247     volatile int garbage = 0;
 248
 249     rcu_register_thread();
 250
 251     *(struct rcu_reader_data **)arg = &rcu_reader;
 252     while (goflag == GOFLAG_INIT) {
 253         g_usleep(1000);
 254     }
 255     while (goflag == GOFLAG_RUN) {
 256         rcu_read_lock();
 257         p = atomic_rcu_read(&rcu_stress_current);
 258         if (p->mbtest == 0) {
 259             n_mberror++;
 260         }
 261         rcu_read_lock();
 262         for (i = 0; i < 100; i++) {
 263             garbage++;
 264         }
 265         rcu_read_unlock();
 266         pc = p->pipe_count;
 267         rcu_read_unlock();
 268         if ((pc > RCU_STRESS_PIPE_LEN) || (pc < 0)) {
 269             pc = RCU_STRESS_PIPE_LEN;
 270         }
 271         rcu_stress_local[pc]++;
 272         n_reads_local++;
 273         if ((++itercnt % 0x1000) == 0) {
 274             synchronize_rcu();
 275         }
 276     }
 277     qemu_mutex_lock(&counts_mutex);
 278     n_reads += n_reads_local;
 279     for (i = 0; i <= RCU_STRESS_PIPE_LEN; i++) {
 280         rcu_stress_count[i] += rcu_stress_local[i];
 281     }
 282     qemu_mutex_unlock(&counts_mutex);
 283
 284     rcu_unregister_thread();
 285     return NULL;
 286 }
 287
 288 static void *rcu_update_stress_test(void *arg)
 289 {
 290     int i;
 291     struct rcu_stress *p;
 292
 293     rcu_register_thread();
 294
 295     *(struct rcu_reader_data **)arg = &rcu_reader;
 296     while (goflag == GOFLAG_INIT) {
 297         g_usleep(1000);
 298     }
 299     while (goflag == GOFLAG_RUN) {
 300         i = rcu_stress_idx + 1;
 301         if (i >= RCU_STRESS_PIPE_LEN) {
 302             i = 0;
 303         }
 304         p = &rcu_stress_array[i];
 305         p->mbtest = 0;
 306         smp_mb();
 307         p->pipe_count = 0;
 308         p->mbtest = 1;
 309         atomic_rcu_set(&rcu_stress_current, p);
 310         rcu_stress_idx = i;
 311         for (i = 0; i < RCU_STRESS_PIPE_LEN; i++) {
 312             if (i != rcu_stress_idx) {
 313                 rcu_stress_array[i].pipe_count++;
 314             }
 315         }
 316         synchronize_rcu();
 317         n_updates++;
 318     }
 319
 320     rcu_unregister_thread();
 321     return NULL;
 322 }
 323
 324 static void *rcu_fake_update_stress_test(void *arg)
 325 {
 326     rcu_register_thread();
 327
 328     *(struct rcu_reader_data **)arg = &rcu_reader;
 329     while (goflag == GOFLAG_INIT) {
 330         g_usleep(1000);
 331     }
 332     while (goflag == GOFLAG_RUN) {
 333         synchronize_rcu();
 334         g_usleep(1000);
 335     }
 336
 337     rcu_unregister_thread();
 338     return NULL;
 339 }
 340
 341 static void stresstest(int nreaders, int duration)
 342 {
 343     int i;
 344
 345     rcu_stress_current = &rcu_stress_array[0];
 346     rcu_stress_current->pipe_count = 0;
 347     rcu_stress_current->mbtest = 1;
 348     for (i = 0; i < nreaders; i++) {
 349         create_thread(rcu_read_stress_test);
 350     }
 351     create_thread(rcu_update_stress_test);
 352     for (i = 0; i < 5; i++) {
 353         create_thread(rcu_fake_update_stress_test);
 354     }
 355     goflag = GOFLAG_RUN;
 356     g_usleep(duration * G_USEC_PER_SEC);
 357     goflag = GOFLAG_STOP;
 358     wait_all_threads();
 359     printf("n_reads: %lld  n_updates: %ld  n_mberror: %d\n",
 360            n_reads, n_updates, n_mberror);
 361     printf("rcu_stress_count:");
 362     for (i = 0; i <= RCU_STRESS_PIPE_LEN; i++) {
 363         printf(" %lld", rcu_stress_count[i]);
 364     }
 365     printf("\n");
 366     exit(0);
 367 }
 368
 369 /* GTest interface */
 370
 371 static void gtest_stress(int nreaders, int duration)
 372 {
 373     int i;
 374
 375     rcu_stress_current = &rcu_stress_array[0];
 376     rcu_stress_current->pipe_count = 0;
 377     rcu_stress_current->mbtest = 1;
 378     for (i = 0; i < nreaders; i++) {
 379         create_thread(rcu_read_stress_test);
 380     }
 381     create_thread(rcu_update_stress_test);
 382     for (i = 0; i < 5; i++) {
 383         create_thread(rcu_fake_update_stress_test);
 384     }
 385     goflag = GOFLAG_RUN;
 386     g_usleep(duration * G_USEC_PER_SEC);
 387     goflag = GOFLAG_STOP;
 388     wait_all_threads();
 389     g_assert_cmpint(n_mberror, ==, 0);
 390     for (i = 2; i <= RCU_STRESS_PIPE_LEN; i++) {
 391         g_assert_cmpint(rcu_stress_count[i], ==, 0);
 392     }
 393 }
 394
 395 static void gtest_stress_1_1(void)
 396 {
 397     gtest_stress(1, 1);
 398 }
 399
 400 static void gtest_stress_10_1(void)
 401 {
 402     gtest_stress(10, 1);
 403 }
 404
 405 static void gtest_stress_1_5(void)
 406 {
 407     gtest_stress(1, 5);
 408 }
 409
 410 static void gtest_stress_10_5(void)
 411 {
 412     gtest_stress(10, 5);
 413 }
 414
 415 /*
 416  * Mainprogram.
 417  */
 418
 419 static void usage(int argc, char *argv[])
 420 {
 421     fprintf(stderr, "Usage: %s [nreaders [ perf | stress ] ]\n", argv[0]);
 422     exit(-1);
 423 }
 424
 425 int main(int argc, char *argv[])
 426 {
 427     int nreaders = 1;
 428     int duration = 1;
 429
 430     qemu_mutex_init(&counts_mutex);
 431     if (argc >= 2 && argv[1][0] == '-') {
 432         g_test_init(&argc, &argv, NULL);
 433         if (g_test_quick()) {
 434             g_test_add_func("/rcu/torture/1reader", gtest_stress_1_1);
 435             g_test_add_func("/rcu/torture/10readers", gtest_stress_10_1);
 436         } else {
 437             g_test_add_func("/rcu/torture/1reader", gtest_stress_1_5);
 438             g_test_add_func("/rcu/torture/10readers", gtest_stress_10_5);
 439         }
 440         return g_test_run();
 441     }
 442
 443     if (argc >= 2) {
 444         nreaders = strtoul(argv[1], NULL, 0);
 445     }
 446     if (argc > 3) {
 447         duration = strtoul(argv[3], NULL, 0);
 448     }
 449     if (argc < 3 || strcmp(argv[2], "stress") == 0) {
 450         stresstest(nreaders, duration);
 451     } else if (strcmp(argv[2], "rperf") == 0) {
 452         rperftest(nreaders, duration);
 453     } else if (strcmp(argv[2], "uperf") == 0) {
 454         uperftest(nreaders, duration);
 455     } else if (strcmp(argv[2], "perf") == 0) {
 456         perftest(nreaders, duration);
 457     }
 458     usage(argc, argv);
 459     return 0;
 460 }