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