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 <glib.h>
  64 #include <stdlib.h>
  65 #include <stdio.h>
  66 #include <string.h>
  67 #include "qemu/atomic.h"
  68 #include "qemu/rcu.h"
  69 #include "qemu/compiler.h"
  70 #include "qemu/thread.h"
  71
  72 long long n_reads = 0LL;
  73 long n_updates = 0L;
  74 int nthreadsrunning;
  75
  76 #define GOFLAG_INIT 0
  77 #define GOFLAG_RUN  1
  78 #define GOFLAG_STOP 2
  79
  80 static volatile int goflag = GOFLAG_INIT;
  81
  82 #define RCU_READ_RUN 1000
  83
  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];
  88 static int n_threads;
  89
  90 static void create_thread(void *(*func)(void *))
  91 {
  92     if (n_threads >= NR_THREADS) {
  93         fprintf(stderr, "Thread limit of %d exceeded!\n", NR_THREADS);
  94         exit(-1);
  95     }
  96     qemu_thread_create(&threads[n_threads], "test", func, &data[n_threads],
  97                        QEMU_THREAD_JOINABLE);
  98     n_threads++;
  99 }
 100
 101 static void wait_all_threads(void)
 102 {
 103     int i;
 104
 105     for (i = 0; i < n_threads; i++) {
 106         qemu_thread_join(&threads[i]);
 107     }
 108     n_threads = 0;
 109 }
 110
 111 /*
 112  * Performance test.
 113  */
 114
 115 static void *rcu_read_perf_test(void *arg)
 116 {
 117     int i;
 118     long long n_reads_local = 0;
 119
 120     rcu_register_thread();
 121
 122     *(struct rcu_reader_data **)arg = &rcu_reader;
 123     atomic_inc(&nthreadsrunning);
 124     while (goflag == GOFLAG_INIT) {
 125         g_usleep(1000);
 126     }
 127     while (goflag == GOFLAG_RUN) {
 128         for (i = 0; i < RCU_READ_RUN; i++) {
 129             rcu_read_lock();
 130             rcu_read_unlock();
 131         }
 132         n_reads_local += RCU_READ_RUN;
 133     }
 134     qemu_mutex_lock(&counts_mutex);
 135     n_reads += n_reads_local;
 136     qemu_mutex_unlock(&counts_mutex);
 137
 138     rcu_unregister_thread();
 139     return NULL;
 140 }
 141
 142 static void *rcu_update_perf_test(void *arg)
 143 {
 144     long long n_updates_local = 0;
 145
 146     rcu_register_thread();
 147
 148     *(struct rcu_reader_data **)arg = &rcu_reader;
 149     atomic_inc(&nthreadsrunning);
 150     while (goflag == GOFLAG_INIT) {
 151         g_usleep(1000);
 152     }
 153     while (goflag == GOFLAG_RUN) {
 154         synchronize_rcu();
 155         n_updates_local++;
 156     }
 157     qemu_mutex_lock(&counts_mutex);
 158     n_updates += n_updates_local;
 159     qemu_mutex_unlock(&counts_mutex);
 160
 161     rcu_unregister_thread();
 162     return NULL;
 163 }
 164
 165 static void perftestinit(void)
 166 {
 167     nthreadsrunning = 0;
 168 }
 169
 170 static void perftestrun(int nthreads, int duration, int nreaders, int nupdaters)
 171 {
 172     while (atomic_read(&nthreadsrunning) < nthreads) {
 173         g_usleep(1000);
 174     }
 175     goflag = GOFLAG_RUN;
 176     g_usleep(duration * G_USEC_PER_SEC);
 177     goflag = GOFLAG_STOP;
 178     wait_all_threads();
 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) /
 183         (double)n_reads),
 184            ((duration * 1000*1000*1000.*(double)nupdaters) /
 185         (double)n_updates));
 186     exit(0);
 187 }
 188
 189 static void perftest(int nreaders, int duration)
 190 {
 191     int i;
 192
 193     perftestinit();
 194     for (i = 0; i < nreaders; i++) {
 195         create_thread(rcu_read_perf_test);
 196     }
 197     create_thread(rcu_update_perf_test);
 198     perftestrun(i + 1, duration, nreaders, 1);
 199 }
 200
 201 static void rperftest(int nreaders, int duration)
 202 {
 203     int i;
 204
 205     perftestinit();
 206     for (i = 0; i < nreaders; i++) {
 207         create_thread(rcu_read_perf_test);
 208     }
 209     perftestrun(i, duration, nreaders, 0);
 210 }
 211
 212 static void uperftest(int nupdaters, int duration)
 213 {
 214     int i;
 215
 216     perftestinit();
 217     for (i = 0; i < nupdaters; i++) {
 218         create_thread(rcu_update_perf_test);
 219     }
 220     perftestrun(i, duration, 0, nupdaters);
 221 }
 222
 223 /*
 224  * Stress test.
 225  */
 226
 227 #define RCU_STRESS_PIPE_LEN 10
 228
 229 struct rcu_stress {
 230     int pipe_count;
 231     int mbtest;
 232 };
 233
 234 struct rcu_stress rcu_stress_array[RCU_STRESS_PIPE_LEN] = { { 0 } };
 235 struct rcu_stress *rcu_stress_current;
 236 int rcu_stress_idx;
 237
 238 int n_mberror;
 239 long long rcu_stress_count[RCU_STRESS_PIPE_LEN + 1];
 240
 241
 242 static void *rcu_read_stress_test(void *arg)
 243 {
 244     int i;
 245     int itercnt = 0;
 246     struct rcu_stress *p;
 247     int pc;
 248     long long n_reads_local = 0;
 249     long long rcu_stress_local[RCU_STRESS_PIPE_LEN + 1] = { 0 };
 250     volatile int garbage = 0;
 251
 252     rcu_register_thread();
 253
 254     *(struct rcu_reader_data **)arg = &rcu_reader;
 255     while (goflag == GOFLAG_INIT) {
 256         g_usleep(1000);
 257     }
 258     while (goflag == GOFLAG_RUN) {
 259         rcu_read_lock();
 260         p = atomic_rcu_read(&rcu_stress_current);
 261         if (p->mbtest == 0) {
 262             n_mberror++;
 263         }
 264         rcu_read_lock();
 265         for (i = 0; i < 100; i++) {
 266             garbage++;
 267         }
 268         rcu_read_unlock();
 269         pc = p->pipe_count;
 270         rcu_read_unlock();
 271         if ((pc > RCU_STRESS_PIPE_LEN) || (pc < 0)) {
 272             pc = RCU_STRESS_PIPE_LEN;
 273         }
 274         rcu_stress_local[pc]++;
 275         n_reads_local++;
 276         if ((++itercnt % 0x1000) == 0) {
 277             synchronize_rcu();
 278         }
 279     }
 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];
 284     }
 285     qemu_mutex_unlock(&counts_mutex);
 286
 287     rcu_unregister_thread();
 288     return NULL;
 289 }
 290
 291 static void *rcu_update_stress_test(void *arg)
 292 {
 293     int i;
 294     struct rcu_stress *p;
 295
 296     rcu_register_thread();
 297
 298     *(struct rcu_reader_data **)arg = &rcu_reader;
 299     while (goflag == GOFLAG_INIT) {
 300         g_usleep(1000);
 301     }
 302     while (goflag == GOFLAG_RUN) {
 303         i = rcu_stress_idx + 1;
 304         if (i >= RCU_STRESS_PIPE_LEN) {
 305             i = 0;
 306         }
 307         p = &rcu_stress_array[i];
 308         p->mbtest = 0;
 309         smp_mb();
 310         p->pipe_count = 0;
 311         p->mbtest = 1;
 312         atomic_rcu_set(&rcu_stress_current, p);
 313         rcu_stress_idx = i;
 314         for (i = 0; i < RCU_STRESS_PIPE_LEN; i++) {
 315             if (i != rcu_stress_idx) {
 316                 rcu_stress_array[i].pipe_count++;
 317             }
 318         }
 319         synchronize_rcu();
 320         n_updates++;
 321     }
 322
 323     rcu_unregister_thread();
 324     return NULL;
 325 }
 326
 327 static void *rcu_fake_update_stress_test(void *arg)
 328 {
 329     rcu_register_thread();
 330
 331     *(struct rcu_reader_data **)arg = &rcu_reader;
 332     while (goflag == GOFLAG_INIT) {
 333         g_usleep(1000);
 334     }
 335     while (goflag == GOFLAG_RUN) {
 336         synchronize_rcu();
 337         g_usleep(1000);
 338     }
 339
 340     rcu_unregister_thread();
 341     return NULL;
 342 }
 343
 344 static void stresstest(int nreaders, int duration)
 345 {
 346     int i;
 347
 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);
 353     }
 354     create_thread(rcu_update_stress_test);
 355     for (i = 0; i < 5; i++) {
 356         create_thread(rcu_fake_update_stress_test);
 357     }
 358     goflag = GOFLAG_RUN;
 359     g_usleep(duration * G_USEC_PER_SEC);
 360     goflag = GOFLAG_STOP;
 361     wait_all_threads();
 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]);
 367     }
 368     printf("\n");
 369     exit(0);
 370 }
 371
 372 /* GTest interface */
 373
 374 static void gtest_stress(int nreaders, int duration)
 375 {
 376     int i;
 377
 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);
 383     }
 384     create_thread(rcu_update_stress_test);
 385     for (i = 0; i < 5; i++) {
 386         create_thread(rcu_fake_update_stress_test);
 387     }
 388     goflag = GOFLAG_RUN;
 389     g_usleep(duration * G_USEC_PER_SEC);
 390     goflag = GOFLAG_STOP;
 391     wait_all_threads();
 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);
 395     }
 396 }
 397
 398 static void gtest_stress_1_1(void)
 399 {
 400     gtest_stress(1, 1);
 401 }
 402
 403 static void gtest_stress_10_1(void)
 404 {
 405     gtest_stress(10, 1);
 406 }
 407
 408 static void gtest_stress_1_5(void)
 409 {
 410     gtest_stress(1, 5);
 411 }
 412
 413 static void gtest_stress_10_5(void)
 414 {
 415     gtest_stress(10, 5);
 416 }
 417
 418 /*
 419  * Mainprogram.
 420  */
 421
 422 static void usage(int argc, char *argv[])
 423 {
 424     fprintf(stderr, "Usage: %s [nreaders [ perf | stress ] ]\n", argv[0]);
 425     exit(-1);
 426 }
 427
 428 int main(int argc, char *argv[])
 429 {
 430     int nreaders = 1;
 431     int duration = 1;
 432
 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);
 439         } else {
 440             g_test_add_func("/rcu/torture/1reader", gtest_stress_1_5);
 441             g_test_add_func("/rcu/torture/10readers", gtest_stress_10_5);
 442         }
 443         return g_test_run();
 444     }
 445
 446     if (argc >= 2) {
 447         nreaders = strtoul(argv[1], NULL, 0);
 448     }
 449     if (argc > 3) {
 450         duration = strtoul(argv[3], NULL, 0);
 451     }
 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);
 460     }
 461     usage(argc, argv);
 462     return 0;
 463 }