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