test_qsbr.c

   1 /*
   2  * test_urcu.c
   3  *
   4  * Userspace RCU library - test program
   5  *
   6  * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #define _GNU_SOURCE
  24 #include <stdio.h>
  25 #include <pthread.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/types.h>
  29 #include <sys/wait.h>
  30 #include <unistd.h>
  31 #include <stdio.h>
  32 #include <assert.h>
  33 #include <sys/syscall.h>
  34 #include <sched.h>
  35
  36 #include "arch.h"
  37
  38 /* Make this big enough to include the POWER5+ L3 cacheline size of 256B */
  39 #define CACHE_LINE_SIZE 4096
  40
  41 /* hardcoded number of CPUs */
  42 #define NR_CPUS 16384
  43
  44 #if defined(_syscall0)
  45 _syscall0(pid_t, gettid)
  46 #elif defined(__NR_gettid)
  47 static inline pid_t gettid(void)
  48 {
  49         return syscall(__NR_gettid);
  50 }
  51 #else
  52 #warning "use pid as tid"
  53 static inline pid_t gettid(void)
  54 {
  55         return getpid();
  56 }
  57 #endif
  58
  59 #define _LGPL_SOURCE
  60 #include "urcu-qsbr.h"
  61
  62 struct test_array {
  63         int a;
  64 };
  65
  66 static volatile int test_go, test_stop;
  67
  68 static unsigned long wdelay;
  69
  70 static struct test_array *test_rcu_pointer;
  71
  72 static unsigned long duration;
  73
  74 /* read-side C.S. duration, in loops */
  75 static unsigned long rduration;
  76
  77 static inline void loop_sleep(unsigned long l)
  78 {
  79         while(l-- != 0)
  80                 cpu_relax();
  81 }
  82
  83 static int verbose_mode;
  84
  85 #define printf_verbose(fmt, args...)            \
  86         do {                                    \
  87                 if (verbose_mode)               \
  88                         printf(fmt, args);      \
  89         } while (0)
  90
  91 static unsigned int cpu_affinities[NR_CPUS];
  92 static unsigned int next_aff = 0;
  93 static int use_affinity = 0;
  94
  95 static void set_affinity(void)
  96 {
  97         cpu_set_t mask;
  98         int cpu;
  99
 100         if (!use_affinity)
 101                 return;
 102
 103         cpu = cpu_affinities[next_aff++];
 104         CPU_ZERO(&mask);
 105         CPU_SET(cpu, &mask);
 106         sched_setaffinity(0, sizeof(mask), &mask);
 107 }
 108
 109
 110
 111 /*
 112  * returns 0 if test should end.
 113  */
 114 static int test_duration_write(void)
 115 {
 116         return !test_stop;
 117 }
 118
 119 static int test_duration_read(void)
 120 {
 121         return !test_stop;
 122 }
 123
 124 static unsigned long long __thread nr_writes;
 125 static unsigned long long __thread nr_reads;
 126
 127 static unsigned int nr_readers;
 128 static unsigned int nr_writers;
 129
 130 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
 131
 132 void rcu_copy_mutex_lock(void)
 133 {
 134         int ret;
 135         ret = pthread_mutex_lock(&rcu_copy_mutex);
 136         if (ret) {
 137                 perror("Error in pthread mutex lock");
 138                 exit(-1);
 139         }
 140 }
 141
 142 void rcu_copy_mutex_unlock(void)
 143 {
 144         int ret;
 145
 146         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 147         if (ret) {
 148                 perror("Error in pthread mutex unlock");
 149                 exit(-1);
 150         }
 151 }
 152
 153 /*
 154  * malloc/free are reusing memory areas too quickly, which does not let us
 155  * test races appropriately. Use a large circular array for allocations.
 156  * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 157  */
 158 #define ARRAY_SIZE (1048576 * nr_writers)
 159 #define ARRAY_POISON 0xDEADBEEF
 160 static int array_index;
 161 static struct test_array *test_array;
 162
 163 static struct test_array *test_array_alloc(void)
 164 {
 165         struct test_array *ret;
 166         int index;
 167
 168         rcu_copy_mutex_lock();
 169         index = array_index % ARRAY_SIZE;
 170         assert(test_array[index].a == ARRAY_POISON ||
 171                 test_array[index].a == 0);
 172         ret = &test_array[index];
 173         array_index++;
 174         if (array_index == ARRAY_SIZE)
 175                 array_index = 0;
 176         rcu_copy_mutex_unlock();
 177         return ret;
 178 }
 179
 180 static void test_array_free(struct test_array *ptr)
 181 {
 182         if (!ptr)
 183                 return;
 184         rcu_copy_mutex_lock();
 185         ptr->a = ARRAY_POISON;
 186         rcu_copy_mutex_unlock();
 187 }
 188
 189 void *thr_reader(void *_count)
 190 {
 191         unsigned long long *count = _count;
 192         struct test_array *local_ptr;
 193
 194         printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
 195                         "reader", pthread_self(), (unsigned long)gettid());
 196
 197         set_affinity();
 198
 199         rcu_register_thread();
 200
 201         while (!test_go)
 202         {
 203         }
 204         smp_mb();
 205
 206         for (;;) {
 207                 _rcu_read_lock();
 208                 local_ptr = _rcu_dereference(test_rcu_pointer);
 209                 debug_yield_read();
 210                 if (local_ptr)
 211                         assert(local_ptr->a == 8);
 212                 if (unlikely(rduration))
 213                         loop_sleep(rduration);
 214                 _rcu_read_unlock();
 215                 nr_reads++;
 216                 /* QS each 1024 reads */
 217                 if (unlikely((nr_reads & ((1 << 10) - 1)) == 0))
 218                         _rcu_quiescent_state();
 219                 if (unlikely(!test_duration_read()))
 220                         break;
 221         }
 222
 223         rcu_unregister_thread();
 224
 225         *count = nr_reads;
 226         printf_verbose("thread_end %s, thread id : %lx, tid %lu\n",
 227                         "reader", pthread_self(), (unsigned long)gettid());
 228         return ((void*)1);
 229
 230 }
 231
 232 void *thr_writer(void *_count)
 233 {
 234         unsigned long long *count = _count;
 235         struct test_array *new, *old;
 236
 237         printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
 238                         "writer", pthread_self(), (unsigned long)gettid());
 239
 240         set_affinity();
 241
 242         while (!test_go)
 243         {
 244         }
 245         smp_mb();
 246
 247         for (;;) {
 248                 new = test_array_alloc();
 249                 rcu_copy_mutex_lock();
 250                 old = test_rcu_pointer;
 251                 if (old)
 252                         assert(old->a == 8);
 253                 new->a = 8;
 254                 old = _rcu_publish_content(&test_rcu_pointer, new);
 255                 rcu_copy_mutex_unlock();
 256                 /* can be done after unlock */
 257                 if (old)
 258                         old->a = 0;
 259                 test_array_free(old);
 260                 nr_writes++;
 261                 if (unlikely(!test_duration_write()))
 262                         break;
 263                 if (unlikely(wdelay))
 264                         loop_sleep(wdelay);
 265         }
 266
 267         printf_verbose("thread_end %s, thread id : %lx, tid %lu\n",
 268                         "writer", pthread_self(), (unsigned long)gettid());
 269         *count = nr_writes;
 270         return ((void*)2);
 271 }
 272
 273 void show_usage(int argc, char **argv)
 274 {
 275         printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
 276 #ifdef DEBUG_YIELD
 277         printf(" [-r] [-w] (yield reader and/or writer)");
 278 #endif
 279         printf(" [-d delay] (writer period (us))");
 280         printf(" [-c duration] (reader C.S. duration (in loops))");
 281         printf(" [-v] (verbose output)");
 282         printf(" [-a cpu#] [-a cpu#]... (affinity)");
 283         printf("\n");
 284 }
 285
 286 int main(int argc, char **argv)
 287 {
 288         int err;
 289         pthread_t *tid_reader, *tid_writer;
 290         void *tret;
 291         unsigned long long *count_reader, *count_writer;
 292         unsigned long long tot_reads = 0, tot_writes = 0;
 293         int i, a;
 294
 295         if (argc < 4) {
 296                 show_usage(argc, argv);
 297                 return -1;
 298         }
 299
 300         err = sscanf(argv[1], "%u", &nr_readers);
 301         if (err != 1) {
 302                 show_usage(argc, argv);
 303                 return -1;
 304         }
 305
 306         err = sscanf(argv[2], "%u", &nr_writers);
 307         if (err != 1) {
 308                 show_usage(argc, argv);
 309                 return -1;
 310         }
 311
 312         err = sscanf(argv[3], "%lu", &duration);
 313         if (err != 1) {
 314                 show_usage(argc, argv);
 315                 return -1;
 316         }
 317
 318         for (i = 4; i < argc; i++) {
 319                 if (argv[i][0] != '-')
 320                         continue;
 321                 switch (argv[i][1]) {
 322 #ifdef DEBUG_YIELD
 323                 case 'r':
 324                         yield_active |= YIELD_READ;
 325                         break;
 326                 case 'w':
 327                         yield_active |= YIELD_WRITE;
 328                         break;
 329 #endif
 330                 case 'a':
 331                         if (argc < i + 2) {
 332                                 show_usage(argc, argv);
 333                                 return -1;
 334                         }
 335                         a = atoi(argv[++i]);
 336                         cpu_affinities[next_aff++] = a;
 337                         use_affinity = 1;
 338                         printf_verbose("Adding CPU %d affinity\n", a);
 339                         break;
 340                 case 'c':
 341                         if (argc < i + 2) {
 342                                 show_usage(argc, argv);
 343                                 return -1;
 344                         }
 345                         rduration = atol(argv[++i]);
 346                         break;
 347                 case 'd':
 348                         if (argc < i + 2) {
 349                                 show_usage(argc, argv);
 350                                 return -1;
 351                         }
 352                         wdelay = atol(argv[++i]);
 353                         break;
 354                 case 'v':
 355                         verbose_mode = 1;
 356                         break;
 357                 }
 358         }
 359
 360         printf_verbose("running test for %lu seconds, %u readers, %u writers.\n",
 361                 duration, nr_readers, nr_writers);
 362         printf_verbose("Writer delay : %lu loops.\n", wdelay);
 363         printf_verbose("Reader duration : %lu loops.\n", rduration);
 364         printf_verbose("thread %-6s, thread id : %lx, tid %lu\n",
 365                         "main", pthread_self(), (unsigned long)gettid());
 366
 367         test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
 368         tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
 369         tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
 370         count_reader = malloc(sizeof(*count_reader) * nr_readers);
 371         count_writer = malloc(sizeof(*count_writer) * nr_writers);
 372
 373         next_aff = 0;
 374
 375         for (i = 0; i < nr_readers; i++) {
 376                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 377                                      &count_reader[i]);
 378                 if (err != 0)
 379                         exit(1);
 380         }
 381         for (i = 0; i < nr_writers; i++) {
 382                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 383                                      &count_writer[i]);
 384                 if (err != 0)
 385                         exit(1);
 386         }
 387
 388         smp_mb();
 389
 390         test_go = 1;
 391
 392         sleep(duration);
 393
 394         test_stop = 1;
 395
 396         for (i = 0; i < nr_readers; i++) {
 397                 err = pthread_join(tid_reader[i], &tret);
 398                 if (err != 0)
 399                         exit(1);
 400                 tot_reads += count_reader[i];
 401         }
 402         for (i = 0; i < nr_writers; i++) {
 403                 err = pthread_join(tid_writer[i], &tret);
 404                 if (err != 0)
 405                         exit(1);
 406                 tot_writes += count_writer[i];
 407         }
 408
 409         printf_verbose("total number of reads : %llu, writes %llu\n", tot_reads,
 410                tot_writes);
 411         printf("SUMMARY %-25s testdur %4lu nr_readers %3u rdur %6lu "
 412                 "nr_writers %3u "
 413                 "wdelay %6lu nr_reads %12llu nr_writes %12llu nr_ops %12llu\n",
 414                 argv[0], duration, nr_readers, rduration,
 415                 nr_writers, wdelay, tot_reads, tot_writes,
 416                 tot_reads + tot_writes);
 417         test_array_free(test_rcu_pointer);
 418         free(test_array);
 419         free(tid_reader);
 420         free(tid_writer);
 421         free(count_reader);
 422         free(count_writer);
 423         return 0;
 424 }