test_urcu.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 #include <stdio.h>
  24 #include <pthread.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sys/types.h>
  28 #include <sys/wait.h>
  29 #include <unistd.h>
  30 #include <stdio.h>
  31 #include <assert.h>
  32 #include <sys/syscall.h>
  33
  34 #include "arch.h"
  35
  36 #if defined(_syscall0)
  37 _syscall0(pid_t, gettid)
  38 #elif defined(__NR_gettid)
  39 static inline pid_t gettid(void)
  40 {
  41         return syscall(__NR_gettid);
  42 }
  43 #else
  44 #warning "use pid as tid"
  45 static inline pid_t gettid(void)
  46 {
  47         return getpid();
  48 }
  49 #endif
  50
  51 #ifndef DYNAMIC_LINK_TEST
  52 #define _LGPL_SOURCE
  53 #else
  54 #define debug_yield_read()
  55 #endif
  56 #include "urcu.h"
  57
  58 struct test_array {
  59         int a;
  60 };
  61
  62 static volatile int test_go, test_stop;
  63
  64 static int wdelay;
  65
  66 static struct test_array *test_rcu_pointer;
  67
  68 static unsigned long duration;
  69
  70 /*
  71  * returns 0 if test should end.
  72  */
  73 static int test_duration_write(void)
  74 {
  75         return !test_stop;
  76 }
  77
  78 static int test_duration_read(void)
  79 {
  80         return !test_stop;
  81 }
  82
  83 static unsigned long long __thread nr_writes;
  84 static unsigned long long __thread nr_reads;
  85
  86 static unsigned int nr_readers;
  87 static unsigned int nr_writers;
  88
  89 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  90
  91 void rcu_copy_mutex_lock(void)
  92 {
  93         int ret;
  94         ret = pthread_mutex_lock(&rcu_copy_mutex);
  95         if (ret) {
  96                 perror("Error in pthread mutex lock");
  97                 exit(-1);
  98         }
  99 }
 100
 101 void rcu_copy_mutex_unlock(void)
 102 {
 103         int ret;
 104
 105         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 106         if (ret) {
 107                 perror("Error in pthread mutex unlock");
 108                 exit(-1);
 109         }
 110 }
 111
 112 /*
 113  * malloc/free are reusing memory areas too quickly, which does not let us
 114  * test races appropriately. Use a large circular array for allocations.
 115  * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 116  */
 117 #define ARRAY_SIZE (1048576 * nr_writers)
 118 #define ARRAY_POISON 0xDEADBEEF
 119 static int array_index;
 120 static struct test_array *test_array;
 121
 122 static struct test_array *test_array_alloc(void)
 123 {
 124         struct test_array *ret;
 125         int index;
 126
 127         rcu_copy_mutex_lock();
 128         index = array_index % ARRAY_SIZE;
 129         assert(test_array[index].a == ARRAY_POISON ||
 130                 test_array[index].a == 0);
 131         ret = &test_array[index];
 132         array_index++;
 133         if (array_index == ARRAY_SIZE)
 134                 array_index = 0;
 135         rcu_copy_mutex_unlock();
 136         return ret;
 137 }
 138
 139 static void test_array_free(struct test_array *ptr)
 140 {
 141         if (!ptr)
 142                 return;
 143         rcu_copy_mutex_lock();
 144         ptr->a = ARRAY_POISON;
 145         rcu_copy_mutex_unlock();
 146 }
 147
 148 void *thr_reader(void *_count)
 149 {
 150         unsigned long long *count = _count;
 151         struct test_array *local_ptr;
 152
 153         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 154                         "reader", pthread_self(), (unsigned long)gettid());
 155
 156         rcu_register_thread();
 157
 158         while (!test_go)
 159         {
 160         }
 161         smp_mb();
 162
 163         for (;;) {
 164                 rcu_read_lock();
 165                 local_ptr = rcu_dereference(test_rcu_pointer);
 166                 debug_yield_read();
 167                 if (local_ptr)
 168                         assert(local_ptr->a == 8);
 169                 rcu_read_unlock();
 170                 nr_reads++;
 171                 if (!test_duration_read())
 172                         break;
 173         }
 174
 175         rcu_unregister_thread();
 176
 177         *count = nr_reads;
 178         printf("thread_end %s, thread id : %lx, tid %lu\n",
 179                         "reader", pthread_self(), (unsigned long)gettid());
 180         return ((void*)1);
 181
 182 }
 183
 184 void *thr_writer(void *_count)
 185 {
 186         unsigned long long *count = _count;
 187         struct test_array *new, *old;
 188
 189         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 190                         "writer", pthread_self(), (unsigned long)gettid());
 191
 192         while (!test_go)
 193         {
 194         }
 195         smp_mb();
 196
 197         for (;;) {
 198                 new = test_array_alloc();
 199                 rcu_copy_mutex_lock();
 200                 old = test_rcu_pointer;
 201                 if (old)
 202                         assert(old->a == 8);
 203                 new->a = 8;
 204                 old = rcu_publish_content(&test_rcu_pointer, new);
 205                 rcu_copy_mutex_unlock();
 206                 /* can be done after unlock */
 207                 if (old)
 208                         old->a = 0;
 209                 test_array_free(old);
 210                 nr_writes++;
 211                 if (!test_duration_write())
 212                         break;
 213                 if (wdelay)
 214                         usleep(wdelay);
 215         }
 216
 217         printf("thread_end %s, thread id : %lx, tid %lu\n",
 218                         "writer", pthread_self(), (unsigned long)gettid());
 219         *count = nr_writes;
 220         return ((void*)2);
 221 }
 222
 223 void show_usage(int argc, char **argv)
 224 {
 225         printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
 226 #ifdef DEBUG_YIELD
 227         printf(" [-r] [-w] (yield reader and/or writer)");
 228 #endif
 229         printf(" [-d delay] (writer period (us))");
 230         printf("\n");
 231 }
 232
 233 int main(int argc, char **argv)
 234 {
 235         int err;
 236         pthread_t *tid_reader, *tid_writer;
 237         void *tret;
 238         unsigned long long *count_reader, *count_writer;
 239         unsigned long long tot_reads = 0, tot_writes = 0;
 240         int i;
 241
 242         if (argc < 4) {
 243                 show_usage(argc, argv);
 244                 return -1;
 245         }
 246
 247         err = sscanf(argv[1], "%u", &nr_readers);
 248         if (err != 1) {
 249                 show_usage(argc, argv);
 250                 return -1;
 251         }
 252
 253         err = sscanf(argv[2], "%u", &nr_writers);
 254         if (err != 1) {
 255                 show_usage(argc, argv);
 256                 return -1;
 257         }
 258
 259         err = sscanf(argv[3], "%lu", &duration);
 260         if (err != 1) {
 261                 show_usage(argc, argv);
 262                 return -1;
 263         }
 264
 265         for (i = 4; i < argc; i++) {
 266                 if (argv[i][0] != '-')
 267                         continue;
 268                 switch (argv[i][1]) {
 269 #ifdef DEBUG_YIELD
 270                 case 'r':
 271                         yield_active |= YIELD_READ;
 272                         break;
 273                 case 'w':
 274                         yield_active |= YIELD_WRITE;
 275                         break;
 276 #endif
 277                 case 'd':
 278                         if (argc < i + 2) {
 279                                 show_usage(argc, argv);
 280                                 return -1;
 281                         }
 282                         wdelay = atoi(argv[++i]);
 283                         break;
 284                 }
 285         }
 286
 287         printf("running test for %lu seconds, %u readers, %u writers.\n",
 288                 duration, nr_readers, nr_writers);
 289         printf("Writer delay : %u us.\n", wdelay);
 290         printf("thread %-6s, thread id : %lx, tid %lu\n",
 291                         "main", pthread_self(), (unsigned long)gettid());
 292
 293         test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
 294         tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
 295         tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
 296         count_reader = malloc(sizeof(*count_reader) * nr_readers);
 297         count_writer = malloc(sizeof(*count_writer) * nr_writers);
 298
 299         for (i = 0; i < nr_readers; i++) {
 300                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 301                                      &count_reader[i]);
 302                 if (err != 0)
 303                         exit(1);
 304         }
 305         for (i = 0; i < nr_writers; i++) {
 306                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 307                                      &count_writer[i]);
 308                 if (err != 0)
 309                         exit(1);
 310         }
 311
 312         smp_mb();
 313
 314         test_go = 1;
 315
 316         sleep(duration);
 317
 318         test_stop = 1;
 319
 320         for (i = 0; i < nr_readers; i++) {
 321                 err = pthread_join(tid_reader[i], &tret);
 322                 if (err != 0)
 323                         exit(1);
 324                 tot_reads += count_reader[i];
 325         }
 326         for (i = 0; i < nr_writers; i++) {
 327                 err = pthread_join(tid_writer[i], &tret);
 328                 if (err != 0)
 329                         exit(1);
 330                 tot_writes += count_writer[i];
 331         }
 332
 333         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 334                tot_writes);
 335         test_array_free(test_rcu_pointer);
 336         free(test_array);
 337         free(tid_reader);
 338         free(tid_writer);
 339         free(count_reader);
 340         free(count_writer);
 341         return 0;
 342 }