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;
  63
  64 static int wdelay;
  65
  66 static struct test_array *test_rcu_pointer;
  67
  68 static unsigned long duration;
  69 static time_t start_time;
  70 static unsigned long __thread duration_interval;
  71 #define DURATION_TEST_DELAY_WRITE 4
  72 #define DURATION_TEST_DELAY_READ 100
  73
  74 /*
  75  * returns 0 if test should end.
  76  */
  77 static int test_duration_write(void)
  78 {
  79         if (duration_interval++ >= DURATION_TEST_DELAY_WRITE) {
  80                 duration_interval = 0;
  81                 if (time(NULL) - start_time >= duration)
  82                         return 0;
  83         }
  84         return 1;
  85 }
  86
  87 static int test_duration_read(void)
  88 {
  89         if (duration_interval++ >= DURATION_TEST_DELAY_READ) {
  90                 duration_interval = 0;
  91                 if (time(NULL) - start_time >= duration)
  92                         return 0;
  93         }
  94         return 1;
  95 }
  96
  97 static unsigned long long __thread nr_writes;
  98 static unsigned long long __thread nr_reads;
  99
 100 static unsigned int nr_readers;
 101 static unsigned int nr_writers;
 102
 103 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
 104
 105 void rcu_copy_mutex_lock(void)
 106 {
 107         int ret;
 108         ret = pthread_mutex_lock(&rcu_copy_mutex);
 109         if (ret) {
 110                 perror("Error in pthread mutex lock");
 111                 exit(-1);
 112         }
 113 }
 114
 115 void rcu_copy_mutex_unlock(void)
 116 {
 117         int ret;
 118
 119         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 120         if (ret) {
 121                 perror("Error in pthread mutex unlock");
 122                 exit(-1);
 123         }
 124 }
 125
 126 /*
 127  * malloc/free are reusing memory areas too quickly, which does not let us
 128  * test races appropriately. Use a large circular array for allocations.
 129  * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 130  */
 131 #define ARRAY_SIZE (1048576 * nr_writers)
 132 #define ARRAY_POISON 0xDEADBEEF
 133 static int array_index;
 134 static struct test_array *test_array;
 135
 136 static struct test_array *test_array_alloc(void)
 137 {
 138         struct test_array *ret;
 139         int index;
 140
 141         rcu_copy_mutex_lock();
 142         index = array_index % ARRAY_SIZE;
 143         assert(test_array[index].a == ARRAY_POISON ||
 144                 test_array[index].a == 0);
 145         ret = &test_array[index];
 146         array_index++;
 147         if (array_index == ARRAY_SIZE)
 148                 array_index = 0;
 149         rcu_copy_mutex_unlock();
 150         return ret;
 151 }
 152
 153 static void test_array_free(struct test_array *ptr)
 154 {
 155         if (!ptr)
 156                 return;
 157         rcu_copy_mutex_lock();
 158         ptr->a = ARRAY_POISON;
 159         rcu_copy_mutex_unlock();
 160 }
 161
 162 void *thr_reader(void *_count)
 163 {
 164         unsigned long long *count = _count;
 165         struct test_array *local_ptr;
 166
 167         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 168                         "reader", pthread_self(), (unsigned long)gettid());
 169
 170         rcu_register_thread();
 171
 172         while (!test_go)
 173         {
 174         }
 175         smp_mb();
 176
 177         for (;;) {
 178                 rcu_read_lock();
 179                 local_ptr = rcu_dereference(test_rcu_pointer);
 180                 debug_yield_read();
 181                 if (local_ptr)
 182                         assert(local_ptr->a == 8);
 183                 rcu_read_unlock();
 184                 nr_reads++;
 185                 if (!test_duration_read())
 186                         break;
 187         }
 188
 189         rcu_unregister_thread();
 190
 191         *count = nr_reads;
 192         printf("thread_end %s, thread id : %lx, tid %lu\n",
 193                         "reader", pthread_self(), (unsigned long)gettid());
 194         return ((void*)1);
 195
 196 }
 197
 198 void *thr_writer(void *_count)
 199 {
 200         unsigned long long *count = _count;
 201         struct test_array *new, *old;
 202
 203         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 204                         "writer", pthread_self(), (unsigned long)gettid());
 205
 206         while (!test_go)
 207         {
 208         }
 209         smp_mb();
 210
 211         for (;;) {
 212                 new = test_array_alloc();
 213                 rcu_copy_mutex_lock();
 214                 old = test_rcu_pointer;
 215                 if (old)
 216                         assert(old->a == 8);
 217                 new->a = 8;
 218                 old = rcu_publish_content(&test_rcu_pointer, new);
 219                 rcu_copy_mutex_unlock();
 220                 /* can be done after unlock */
 221                 if (old)
 222                         old->a = 0;
 223                 test_array_free(old);
 224                 nr_writes++;
 225                 if (!test_duration_write())
 226                         break;
 227                 if (wdelay)
 228                         usleep(wdelay);
 229         }
 230
 231         printf("thread_end %s, thread id : %lx, tid %lu\n",
 232                         "writer", pthread_self(), (unsigned long)gettid());
 233         *count = nr_writes;
 234         return ((void*)2);
 235 }
 236
 237 void show_usage(int argc, char **argv)
 238 {
 239         printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
 240 #ifdef DEBUG_YIELD
 241         printf(" [-r] [-w] (yield reader and/or writer)");
 242 #endif
 243         printf(" [-d delay] (writer period (us))");
 244         printf("\n");
 245 }
 246
 247 int main(int argc, char **argv)
 248 {
 249         int err;
 250         pthread_t *tid_reader, *tid_writer;
 251         void *tret;
 252         unsigned long long *count_reader, *count_writer;
 253         unsigned long long tot_reads = 0, tot_writes = 0;
 254         int i;
 255
 256         if (argc < 4) {
 257                 show_usage(argc, argv);
 258                 return -1;
 259         }
 260
 261         err = sscanf(argv[1], "%u", &nr_readers);
 262         if (err != 1) {
 263                 show_usage(argc, argv);
 264                 return -1;
 265         }
 266
 267         err = sscanf(argv[2], "%u", &nr_writers);
 268         if (err != 1) {
 269                 show_usage(argc, argv);
 270                 return -1;
 271         }
 272
 273         err = sscanf(argv[3], "%lu", &duration);
 274         if (err != 1) {
 275                 show_usage(argc, argv);
 276                 return -1;
 277         }
 278
 279         for (i = 4; i < argc; i++) {
 280                 if (argv[i][0] != '-')
 281                         continue;
 282                 switch (argv[i][1]) {
 283 #ifdef DEBUG_YIELD
 284                 case 'r':
 285                         yield_active |= YIELD_READ;
 286                         break;
 287                 case 'w':
 288                         yield_active |= YIELD_WRITE;
 289                         break;
 290 #endif
 291                 case 'd':
 292                         if (argc < i + 2) {
 293                                 show_usage(argc, argv);
 294                                 return -1;
 295                         }
 296                         wdelay = atoi(argv[++i]);
 297                         break;
 298                 }
 299         }
 300
 301         printf("running test for %lu seconds, %u readers, %u writers.\n",
 302                 duration, nr_readers, nr_writers);
 303         printf("Writer delay : %u us.\n", wdelay);
 304         printf("thread %-6s, thread id : %lx, tid %lu\n",
 305                         "main", pthread_self(), (unsigned long)gettid());
 306
 307         test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
 308         tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
 309         tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
 310         count_reader = malloc(sizeof(*count_reader) * nr_readers);
 311         count_writer = malloc(sizeof(*count_writer) * nr_writers);
 312
 313         for (i = 0; i < nr_readers; i++) {
 314                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 315                                      &count_reader[i]);
 316                 if (err != 0)
 317                         exit(1);
 318         }
 319         for (i = 0; i < nr_writers; i++) {
 320                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 321                                      &count_writer[i]);
 322                 if (err != 0)
 323                         exit(1);
 324         }
 325
 326         start_time = time(NULL);
 327         test_go = 1;
 328         smp_mb();
 329
 330         for (i = 0; i < nr_readers; i++) {
 331                 err = pthread_join(tid_reader[i], &tret);
 332                 if (err != 0)
 333                         exit(1);
 334                 tot_reads += count_reader[i];
 335         }
 336         for (i = 0; i < nr_writers; i++) {
 337                 err = pthread_join(tid_writer[i], &tret);
 338                 if (err != 0)
 339                         exit(1);
 340                 tot_writes += count_writer[i];
 341         }
 342
 343         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 344                tot_writes);
 345         test_array_free(test_rcu_pointer);
 346         free(test_array);
 347         free(tid_reader);
 348         free(tid_writer);
 349         free(count_reader);
 350         free(count_writer);
 351         return 0;
 352 }