rcutorture.h

   1 /*
   2  * rcutorture.h: simple user-level performance/stress test of RCU.
   3  *
   4  * Usage:
   5  *      ./rcu <nreaders> rperf [ <cpustride> ]
   6  *              Run a read-side performance test with the specified
   7  *              number of readers spaced by <cpustride>.
   8  *              Thus "./rcu 16 rperf 2" would run 16 readers on even-numbered
   9  *              CPUs from 0 to 30.
  10  *      ./rcu <nupdaters> uperf [ <cpustride> ]
  11  *              Run an update-side performance test with the specified
  12  *              number of updaters and specified CPU spacing.
  13  *      ./rcu <nreaders> perf [ <cpustride> ]
  14  *              Run a combined read/update performance test with the specified
  15  *              number of readers and one updater and specified CPU spacing.
  16  *              The readers run on the low-numbered CPUs and the updater
  17  *              of the highest-numbered CPU.
  18  *
  19  * The above tests produce output as follows:
  20  *
  21  * n_reads: 46008000  n_updates: 146026  nreaders: 2  nupdaters: 1 duration: 1
  22  * ns/read: 43.4707  ns/update: 6848.1
  23  *
  24  * The first line lists the total number of RCU reads and updates executed
  25  * during the test, the number of reader threads, the number of updater
  26  * threads, and the duration of the test in seconds.  The second line
  27  * lists the average duration of each type of operation in nanoseconds,
  28  * or "nan" if the corresponding type of operation was not performed.
  29  *
  30  *      ./rcu <nreaders> stress
  31  *              Run a stress test with the specified number of readers and
  32  *              one updater.  None of the threads are affinitied to any
  33  *              particular CPU.
  34  *
  35  * This test produces output as follows:
  36  *
  37  * n_reads: 114633217  n_updates: 3903415  n_mberror: 0
  38  * rcu_stress_count: 114618391 14826 0 0 0 0 0 0 0 0 0
  39  *
  40  * The first line lists the number of RCU read and update operations
  41  * executed, followed by the number of memory-ordering violations
  42  * (which will be zero in a correct RCU implementation).  The second
  43  * line lists the number of readers observing progressively more stale
  44  * data.  A correct RCU implementation will have all but the first two
  45  * numbers non-zero.
  46  *
  47  * This program is free software; you can redistribute it and/or modify
  48  * it under the terms of the GNU General Public License as published by
  49  * the Free Software Foundation; either version 2 of the License, or
  50  * (at your option) any later version.
  51  *
  52  * This program is distributed in the hope that it will be useful,
  53  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  54  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  55  * GNU General Public License for more details.
  56  *
  57  * You should have received a copy of the GNU General Public License
  58  * along with this program; if not, write to the Free Software
  59  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  60  *
  61  * Copyright (c) 2008 Paul E. McKenney, IBM Corporation.
  62  */
  63
  64 /*
  65  * Test variables.
  66  */
  67
  68 DEFINE_PER_THREAD(long long, n_reads_pt);
  69 DEFINE_PER_THREAD(long long, n_updates_pt);
  70
  71 long long n_reads = 0LL;
  72 long n_updates = 0L;
  73 atomic_t nthreadsrunning;
  74 char argsbuf[64];
  75
  76 #define GOFLAG_INIT 0
  77 #define GOFLAG_RUN  1
  78 #define GOFLAG_STOP 2
  79
  80 int goflag __attribute__((__aligned__(CACHE_LINE_SIZE))) = GOFLAG_INIT;
  81
  82 #define RCU_READ_RUN 1000
  83
  84 //MD
  85 #define RCU_READ_NESTABLE
  86
  87 #ifdef RCU_READ_NESTABLE
  88 #define rcu_read_lock_nest() rcu_read_lock()
  89 #define rcu_read_unlock_nest() rcu_read_unlock()
  90 #else /* #ifdef RCU_READ_NESTABLE */
  91 #define rcu_read_lock_nest()
  92 #define rcu_read_unlock_nest()
  93 #endif /* #else #ifdef RCU_READ_NESTABLE */
  94
  95 #ifndef mark_rcu_quiescent_state
  96 #define mark_rcu_quiescent_state() do ; while (0)
  97 #endif /* #ifdef mark_rcu_quiescent_state */
  98
  99 #ifndef put_thread_offline
 100 #define put_thread_offline()            do ; while (0)
 101 #define put_thread_online()             do ; while (0)
 102 #define put_thread_online_delay()       do ; while (0)
 103 #else /* #ifndef put_thread_offline */
 104 #define put_thread_online_delay()       synchronize_rcu()
 105 #endif /* #else #ifndef put_thread_offline */
 106
 107 /*
 108  * Performance test.
 109  */
 110
 111 void *rcu_read_perf_test(void *arg)
 112 {
 113         int i;
 114         int me = (long)arg;
 115         long long n_reads_local = 0;
 116
 117         rcu_register_thread();
 118         run_on(me);
 119         atomic_inc(&nthreadsrunning);
 120         while (goflag == GOFLAG_INIT)
 121                 poll(NULL, 0, 1);
 122         mark_rcu_quiescent_state();
 123         while (goflag == GOFLAG_RUN) {
 124                 for (i = 0; i < RCU_READ_RUN; i++) {
 125                         rcu_read_lock();
 126                         /* rcu_read_lock_nest(); */
 127                         /* rcu_read_unlock_nest(); */
 128                         rcu_read_unlock();
 129                 }
 130                 n_reads_local += RCU_READ_RUN;
 131                 mark_rcu_quiescent_state();
 132         }
 133         __get_thread_var(n_reads_pt) += n_reads_local;
 134         put_thread_offline();
 135         rcu_unregister_thread();
 136
 137         return (NULL);
 138 }
 139
 140 void *rcu_update_perf_test(void *arg)
 141 {
 142         long long n_updates_local = 0;
 143
 144         atomic_inc(&nthreadsrunning);
 145         while (goflag == GOFLAG_INIT)
 146                 poll(NULL, 0, 1);
 147         while (goflag == GOFLAG_RUN) {
 148                 synchronize_rcu();
 149                 n_updates_local++;
 150         }
 151         __get_thread_var(n_updates_pt) += n_updates_local;
 152         return NULL;
 153 }
 154
 155 void perftestinit(void)
 156 {
 157         init_per_thread(n_reads_pt, 0LL);
 158         init_per_thread(n_updates_pt, 0LL);
 159         atomic_set(&nthreadsrunning, 0);
 160 }
 161
 162 void perftestrun(int nthreads, int nreaders, int nupdaters)
 163 {
 164         int t;
 165         int duration = 1;
 166
 167         smp_mb();
 168         while (atomic_read(&nthreadsrunning) < nthreads)
 169                 poll(NULL, 0, 1);
 170         goflag = GOFLAG_RUN;
 171         smp_mb();
 172         sleep(duration);
 173         smp_mb();
 174         goflag = GOFLAG_STOP;
 175         smp_mb();
 176         wait_all_threads();
 177         for_each_thread(t) {
 178                 n_reads += per_thread(n_reads_pt, t);
 179                 n_updates += per_thread(n_updates_pt, t);
 180         }
 181         printf("n_reads: %lld  n_updates: %ld  nreaders: %d  nupdaters: %d duration: %d\n",
 182                n_reads, n_updates, nreaders, nupdaters, duration);
 183         printf("ns/read: %g  ns/update: %g\n",
 184                ((duration * 1000*1000*1000.*(double)nreaders) /
 185                 (double)n_reads),
 186                ((duration * 1000*1000*1000.*(double)nupdaters) /
 187                 (double)n_updates));
 188         exit(0);
 189 }
 190
 191 void perftest(int nreaders, int cpustride)
 192 {
 193         int i;
 194         long arg;
 195
 196         perftestinit();
 197         for (i = 0; i < nreaders; i++) {
 198                 arg = (long)(i * cpustride);
 199                 create_thread(rcu_read_perf_test, (void *)arg);
 200         }
 201         arg = (long)(i * cpustride);
 202         create_thread(rcu_update_perf_test, (void *)arg);
 203         perftestrun(i + 1, nreaders, 1);
 204 }
 205
 206 void rperftest(int nreaders, int cpustride)
 207 {
 208         int i;
 209         long arg;
 210
 211         perftestinit();
 212         init_per_thread(n_reads_pt, 0LL);
 213         for (i = 0; i < nreaders; i++) {
 214                 arg = (long)(i * cpustride);
 215                 create_thread(rcu_read_perf_test, (void *)arg);
 216         }
 217         perftestrun(i, nreaders, 0);
 218 }
 219
 220 void uperftest(int nupdaters, int cpustride)
 221 {
 222         int i;
 223         long arg;
 224
 225         perftestinit();
 226         init_per_thread(n_reads_pt, 0LL);
 227         for (i = 0; i < nupdaters; i++) {
 228                 arg = (long)(i * cpustride);
 229                 create_thread(rcu_update_perf_test, (void *)arg);
 230         }
 231         perftestrun(i, 0, nupdaters);
 232 }
 233
 234 /*
 235  * Stress test.
 236  */
 237
 238 #define RCU_STRESS_PIPE_LEN 10
 239
 240 struct rcu_stress {
 241         int pipe_count;
 242         int mbtest;
 243 };
 244
 245 struct rcu_stress rcu_stress_array[RCU_STRESS_PIPE_LEN] = { { 0 } };
 246 struct rcu_stress *rcu_stress_current;
 247 int rcu_stress_idx = 0;
 248
 249 int n_mberror = 0;
 250 DEFINE_PER_THREAD(long long [RCU_STRESS_PIPE_LEN + 1], rcu_stress_count);
 251
 252 int garbage = 0;
 253
 254 void *rcu_read_stress_test(void *arg)
 255 {
 256         int i;
 257         int itercnt = 0;
 258         struct rcu_stress *p;
 259         int pc;
 260
 261         rcu_register_thread();
 262         while (goflag == GOFLAG_INIT)
 263                 poll(NULL, 0, 1);
 264         mark_rcu_quiescent_state();
 265         while (goflag == GOFLAG_RUN) {
 266                 rcu_read_lock();
 267                 p = rcu_dereference(rcu_stress_current);
 268                 if (p->mbtest == 0)
 269                         n_mberror++;
 270                 rcu_read_lock_nest();
 271                 for (i = 0; i < 100; i++)
 272                         garbage++;
 273                 rcu_read_unlock_nest();
 274                 pc = p->pipe_count;
 275                 rcu_read_unlock();
 276                 if ((pc > RCU_STRESS_PIPE_LEN) || (pc < 0))
 277                         pc = RCU_STRESS_PIPE_LEN;
 278                 __get_thread_var(rcu_stress_count)[pc]++;
 279                 __get_thread_var(n_reads_pt)++;
 280                 mark_rcu_quiescent_state();
 281                 if ((++itercnt % 0x1000) == 0) {
 282                         put_thread_offline();
 283                         put_thread_online_delay();
 284                         put_thread_online();
 285                 }
 286         }
 287         put_thread_offline();
 288         rcu_unregister_thread();
 289
 290         return (NULL);
 291 }
 292
 293 void *rcu_update_stress_test(void *arg)
 294 {
 295         int i;
 296         struct rcu_stress *p;
 297
 298         while (goflag == GOFLAG_INIT)
 299                 poll(NULL, 0, 1);
 300         while (goflag == GOFLAG_RUN) {
 301                 i = rcu_stress_idx + 1;
 302                 if (i >= RCU_STRESS_PIPE_LEN)
 303                         i = 0;
 304                 p = &rcu_stress_array[i];
 305                 p->mbtest = 0;
 306                 smp_mb();
 307                 p->pipe_count = 0;
 308                 p->mbtest = 1;
 309                 rcu_assign_pointer(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                 synchronize_rcu();
 315                 n_updates++;
 316         }
 317         return NULL;
 318 }
 319
 320 void *rcu_fake_update_stress_test(void *arg)
 321 {
 322         while (goflag == GOFLAG_INIT)
 323                 poll(NULL, 0, 1);
 324         while (goflag == GOFLAG_RUN) {
 325                 synchronize_rcu();
 326                 poll(NULL, 0, 1);
 327         }
 328         return NULL;
 329 }
 330
 331 void stresstest(int nreaders)
 332 {
 333         int i;
 334         int t;
 335         long long *p;
 336         long long sum;
 337
 338         init_per_thread(n_reads_pt, 0LL);
 339         for_each_thread(t) {
 340                 p = &per_thread(rcu_stress_count,t)[0];
 341                 for (i = 0; i <= RCU_STRESS_PIPE_LEN; i++)
 342                         p[i] = 0LL;
 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, NULL);
 349         create_thread(rcu_update_stress_test, NULL);
 350         for (i = 0; i < 5; i++)
 351                 create_thread(rcu_fake_update_stress_test, NULL);
 352         smp_mb();
 353         goflag = GOFLAG_RUN;
 354         smp_mb();
 355         sleep(10);
 356         smp_mb();
 357         goflag = GOFLAG_STOP;
 358         smp_mb();
 359         wait_all_threads();
 360         for_each_thread(t)
 361                 n_reads += per_thread(n_reads_pt, t);
 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                 sum = 0LL;
 367                 for_each_thread(t) {
 368                         sum += per_thread(rcu_stress_count, t)[i];
 369                 }
 370                 printf(" %lld", sum);
 371         }
 372         printf("\n");
 373         exit(0);
 374 }
 375
 376 /*
 377  * Mainprogram.
 378  */
 379
 380 void usage(int argc, char *argv[])
 381 {
 382         fprintf(stderr, "Usage: %s [nreaders [ perf | stress ] ]\n", argv[0]);
 383         exit(-1);
 384 }
 385
 386 int main(int argc, char *argv[])
 387 {
 388         int nreaders = 1;
 389         int cpustride = 1;
 390
 391         smp_init();
 392         //rcu_init();
 393
 394 #ifdef DEBUG_YIELD
 395         yield_active |= YIELD_READ;
 396         yield_active |= YIELD_WRITE;
 397 #endif
 398
 399         if (argc > 1) {
 400                 nreaders = strtoul(argv[1], NULL, 0);
 401                 if (argc == 2)
 402                         perftest(nreaders, cpustride);
 403                 if (argc > 3)
 404                         cpustride = strtoul(argv[3], NULL, 0);
 405                 if (strcmp(argv[2], "perf") == 0)
 406                         perftest(nreaders, cpustride);
 407                 else if (strcmp(argv[2], "rperf") == 0)
 408                         rperftest(nreaders, cpustride);
 409                 else if (strcmp(argv[2], "uperf") == 0)
 410                         uperftest(nreaders, cpustride);
 411                 else if (strcmp(argv[2], "stress") == 0)
 412                         stresstest(nreaders);
 413                 usage(argc, argv);
 414         }
 415         perftest(nreaders, cpustride);
 416 }