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 #if defined(_syscall0)
  35 _syscall0(pid_t, gettid)
  36 #elif defined(__NR_gettid)
  37 static inline pid_t gettid(void)
  38 {
  39         return syscall(__NR_gettid);
  40 }
  41 #else
  42 #warning "use pid as tid"
  43 static inline pid_t gettid(void)
  44 {
  45         return getpid();
  46 }
  47 #endif
  48
  49 #ifndef DYNAMIC_LINK_TEST
  50 #define _LGPL_SOURCE
  51 #else
  52 #define debug_yield_read()
  53 #endif
  54 #include "urcu.h"
  55
  56 struct test_array {
  57         int a;
  58 };
  59
  60 static volatile int test_go;
  61
  62 static int wdelay;
  63
  64 static struct test_array *test_rcu_pointer;
  65
  66 static unsigned long duration;
  67 static time_t start_time;
  68 static unsigned long __thread duration_interval;
  69 #define DURATION_TEST_DELAY_WRITE 4
  70 #define DURATION_TEST_DELAY_READ 100
  71
  72 /*
  73  * returns 0 if test should end.
  74  */
  75 static int test_duration_write(void)
  76 {
  77         if (duration_interval++ >= DURATION_TEST_DELAY_WRITE) {
  78                 duration_interval = 0;
  79                 if (time(NULL) - start_time >= duration)
  80                         return 0;
  81         }
  82         return 1;
  83 }
  84
  85 static int test_duration_read(void)
  86 {
  87         if (duration_interval++ >= DURATION_TEST_DELAY_READ) {
  88                 duration_interval = 0;
  89                 if (time(NULL) - start_time >= duration)
  90                         return 0;
  91         }
  92         return 1;
  93 }
  94
  95 static unsigned long long __thread nr_writes;
  96 static unsigned long long __thread nr_reads;
  97
  98 static unsigned int nr_readers;
  99 static unsigned int nr_writers;
 100
 101 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
 102
 103 void rcu_copy_mutex_lock(void)
 104 {
 105         int ret;
 106         ret = pthread_mutex_lock(&rcu_copy_mutex);
 107         if (ret) {
 108                 perror("Error in pthread mutex lock");
 109                 exit(-1);
 110         }
 111 }
 112
 113 void rcu_copy_mutex_unlock(void)
 114 {
 115         int ret;
 116
 117         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 118         if (ret) {
 119                 perror("Error in pthread mutex unlock");
 120                 exit(-1);
 121         }
 122 }
 123
 124 /*
 125  * malloc/free are reusing memory areas too quickly, which does not let us
 126  * test races appropriately. Use a large circular array for allocations.
 127  * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 128  */
 129 #define ARRAY_SIZE (1048576 * nr_writers)
 130 #define ARRAY_POISON 0xDEADBEEF
 131 static int array_index;
 132 static struct test_array *test_array;
 133
 134 static struct test_array *test_array_alloc(void)
 135 {
 136         struct test_array *ret;
 137         int index;
 138
 139         rcu_copy_mutex_lock();
 140         index = array_index % ARRAY_SIZE;
 141         assert(test_array[index].a == ARRAY_POISON ||
 142                 test_array[index].a == 0);
 143         ret = &test_array[index];
 144         array_index++;
 145         if (array_index == ARRAY_SIZE)
 146                 array_index = 0;
 147         rcu_copy_mutex_unlock();
 148         return ret;
 149 }
 150
 151 static void test_array_free(struct test_array *ptr)
 152 {
 153         if (!ptr)
 154                 return;
 155         rcu_copy_mutex_lock();
 156         ptr->a = ARRAY_POISON;
 157         rcu_copy_mutex_unlock();
 158 }
 159
 160 void *thr_reader(void *_count)
 161 {
 162         unsigned long long *count = _count;
 163         struct test_array *local_ptr;
 164
 165         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 166                         "reader", pthread_self(), (unsigned long)gettid());
 167
 168         rcu_register_thread();
 169
 170         while (!test_go)
 171         {
 172         }
 173
 174         for (;;) {
 175                 rcu_read_lock();
 176                 local_ptr = rcu_dereference(test_rcu_pointer);
 177                 debug_yield_read();
 178                 if (local_ptr)
 179                         assert(local_ptr->a == 8);
 180                 rcu_read_unlock();
 181                 nr_reads++;
 182                 if (!test_duration_read())
 183                         break;
 184         }
 185
 186         rcu_unregister_thread();
 187
 188         *count = nr_reads;
 189         printf("thread_end %s, thread id : %lx, tid %lu\n",
 190                         "reader", pthread_self(), (unsigned long)gettid());
 191         return ((void*)1);
 192
 193 }
 194
 195 void *thr_writer(void *_count)
 196 {
 197         unsigned long long *count = _count;
 198         struct test_array *new, *old;
 199
 200         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 201                         "writer", pthread_self(), (unsigned long)gettid());
 202
 203         while (!test_go)
 204         {
 205         }
 206
 207         for (;;) {
 208                 new = test_array_alloc();
 209                 rcu_copy_mutex_lock();
 210                 old = test_rcu_pointer;
 211                 if (old)
 212                         assert(old->a == 8);
 213                 new->a = 8;
 214                 old = rcu_publish_content(&test_rcu_pointer, new);
 215                 rcu_copy_mutex_unlock();
 216                 /* can be done after unlock */
 217                 if (old)
 218                         old->a = 0;
 219                 test_array_free(old);
 220                 nr_writes++;
 221                 if (!test_duration_write())
 222                         break;
 223                 if (wdelay)
 224                         usleep(wdelay);
 225         }
 226
 227         printf("thread_end %s, thread id : %lx, tid %lu\n",
 228                         "writer", pthread_self(), (unsigned long)gettid());
 229         *count = nr_writes;
 230         return ((void*)2);
 231 }
 232
 233 void show_usage(int argc, char **argv)
 234 {
 235         printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
 236 #ifdef DEBUG_YIELD
 237         printf(" [-r] [-w] (yield reader and/or writer)");
 238 #endif
 239         printf(" [-d delay] (writer period)");
 240         printf("\n");
 241 }
 242
 243 int main(int argc, char **argv)
 244 {
 245         int err;
 246         pthread_t *tid_reader, *tid_writer;
 247         void *tret;
 248         unsigned long long *count_reader, *count_writer;
 249         unsigned long long tot_reads = 0, tot_writes = 0;
 250         int i;
 251
 252         if (argc < 4) {
 253                 show_usage(argc, argv);
 254                 return -1;
 255         }
 256
 257         err = sscanf(argv[1], "%u", &nr_readers);
 258         if (err != 1) {
 259                 show_usage(argc, argv);
 260                 return -1;
 261         }
 262
 263         err = sscanf(argv[2], "%u", &nr_writers);
 264         if (err != 1) {
 265                 show_usage(argc, argv);
 266                 return -1;
 267         }
 268
 269         err = sscanf(argv[3], "%lu", &duration);
 270         if (err != 1) {
 271                 show_usage(argc, argv);
 272                 return -1;
 273         }
 274
 275         for (i = 4; i < argc; i++) {
 276                 if (argv[i][0] != '-')
 277                         continue;
 278                 switch (argv[i][1]) {
 279 #ifdef DEBUG_YIELD
 280                 case 'r':
 281                         yield_active |= YIELD_READ;
 282                         break;
 283                 case 'w':
 284                         yield_active |= YIELD_WRITE;
 285                         break;
 286 #endif
 287                 case 'd':
 288                         if (argc < i + 1) {
 289                                 show_usage(argc, argv);
 290                                 return -1;
 291                         }
 292                         wdelay = atoi(argv[++i]);
 293                         break;
 294                 }
 295         }
 296
 297         printf("running test for %lu seconds, %u readers, %u writers.\n",
 298                 duration, nr_readers, nr_writers);
 299         printf("Writer delay : %u us.\n", wdelay);
 300         start_time = time(NULL);
 301         printf("thread %-6s, thread id : %lx, tid %lu\n",
 302                         "main", pthread_self(), (unsigned long)gettid());
 303
 304         test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
 305         tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
 306         tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
 307         count_reader = malloc(sizeof(*count_reader) * nr_readers);
 308         count_writer = malloc(sizeof(*count_writer) * nr_writers);
 309
 310         for (i = 0; i < nr_readers; i++) {
 311                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 312                                      &count_reader[i]);
 313                 if (err != 0)
 314                         exit(1);
 315         }
 316         for (i = 0; i < nr_writers; i++) {
 317                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 318                                      &count_writer[i]);
 319                 if (err != 0)
 320                         exit(1);
 321         }
 322
 323         test_go = 1;
 324
 325         for (i = 0; i < nr_readers; i++) {
 326                 err = pthread_join(tid_reader[i], &tret);
 327                 if (err != 0)
 328                         exit(1);
 329                 tot_reads += count_reader[i];
 330         }
 331         for (i = 0; i < nr_writers; i++) {
 332                 err = pthread_join(tid_writer[i], &tret);
 333                 if (err != 0)
 334                         exit(1);
 335                 tot_writes += count_writer[i];
 336         }
 337
 338         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 339                tot_writes);
 340         test_array_free(test_rcu_pointer);
 341         free(test_array);
 342         free(tid_reader);
 343         free(tid_writer);
 344         free(count_reader);
 345         free(count_writer);
 346         return 0;
 347 }