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 int no_writer_delay;
  61
  62 static struct test_array *test_rcu_pointer;
  63
  64 static unsigned long duration;
  65 static time_t start_time;
  66 static unsigned long __thread duration_interval;
  67 #define DURATION_TEST_DELAY_WRITE 4
  68 #define DURATION_TEST_DELAY_READ 100
  69
  70 /*
  71  * returns 0 if test should end.
  72  */
  73 static int test_duration_write(void)
  74 {
  75         if (duration_interval++ >= DURATION_TEST_DELAY_WRITE) {
  76                 duration_interval = 0;
  77                 if (time(NULL) - start_time >= duration)
  78                         return 0;
  79         }
  80         return 1;
  81 }
  82
  83 static int test_duration_read(void)
  84 {
  85         if (duration_interval++ >= DURATION_TEST_DELAY_READ) {
  86                 duration_interval = 0;
  87                 if (time(NULL) - start_time >= duration)
  88                         return 0;
  89         }
  90         return 1;
  91 }
  92
  93 #define NR_READ 10
  94 #define NR_WRITE 9
  95
  96 static unsigned long long __thread nr_writes;
  97 static unsigned long long __thread nr_reads;
  98
  99 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
 100
 101 void rcu_copy_mutex_lock(void)
 102 {
 103         int ret;
 104         ret = pthread_mutex_lock(&rcu_copy_mutex);
 105         if (ret) {
 106                 perror("Error in pthread mutex lock");
 107                 exit(-1);
 108         }
 109 }
 110
 111 void rcu_copy_mutex_unlock(void)
 112 {
 113         int ret;
 114
 115         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 116         if (ret) {
 117                 perror("Error in pthread mutex unlock");
 118                 exit(-1);
 119         }
 120 }
 121
 122 /*
 123  * malloc/free are reusing memory areas too quickly, which does not let us
 124  * test races appropriately. Use a large circular array for allocations.
 125  * ARRAY_SIZE is larger than NR_WRITE, which insures we never run over our tail.
 126  */
 127 #define ARRAY_SIZE (1048576 * NR_WRITE)
 128 #define ARRAY_POISON 0xDEADBEEF
 129 static int array_index;
 130 static struct test_array test_array[ARRAY_SIZE];
 131
 132 static struct test_array *test_array_alloc(void)
 133 {
 134         struct test_array *ret;
 135         int index;
 136
 137         rcu_copy_mutex_lock();
 138         index = array_index % ARRAY_SIZE;
 139         assert(test_array[index].a == ARRAY_POISON ||
 140                 test_array[index].a == 0);
 141         ret = &test_array[index];
 142         array_index++;
 143         if (array_index == ARRAY_SIZE)
 144                 array_index = 0;
 145         rcu_copy_mutex_unlock();
 146         return ret;
 147 }
 148
 149 static void test_array_free(struct test_array *ptr)
 150 {
 151         if (!ptr)
 152                 return;
 153         rcu_copy_mutex_lock();
 154         ptr->a = ARRAY_POISON;
 155         rcu_copy_mutex_unlock();
 156 }
 157
 158 void *thr_reader(void *_count)
 159 {
 160         unsigned long long *count = _count;
 161         struct test_array *local_ptr;
 162
 163         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 164                         "reader", pthread_self(), (unsigned long)gettid());
 165
 166         rcu_register_thread();
 167
 168         for (;;) {
 169                 rcu_read_lock();
 170                 local_ptr = rcu_dereference(test_rcu_pointer);
 171                 debug_yield_read();
 172                 if (local_ptr)
 173                         assert(local_ptr->a == 8);
 174                 rcu_read_unlock();
 175                 nr_reads++;
 176                 if (!test_duration_read())
 177                         break;
 178         }
 179
 180         rcu_unregister_thread();
 181
 182         *count = nr_reads;
 183         printf("thread_end %s, thread id : %lx, tid %lu\n",
 184                         "reader", pthread_self(), (unsigned long)gettid());
 185         return ((void*)1);
 186
 187 }
 188
 189 void *thr_writer(void *_count)
 190 {
 191         unsigned long long *count = _count;
 192         struct test_array *new, *old;
 193
 194         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 195                         "writer", pthread_self(), (unsigned long)gettid());
 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 (!no_writer_delay)
 214                         usleep(1);
 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 duration (s)", argv[0]);
 226 #ifdef DEBUG_YIELD
 227         printf(" [-r] [-w] (yield reader and/or writer)");
 228 #endif
 229         printf(" [-n] (disable writer delay)");
 230         printf("\n");
 231 }
 232
 233 int main(int argc, char **argv)
 234 {
 235         int err;
 236         pthread_t tid_reader[NR_READ], tid_writer[NR_WRITE];
 237         void *tret;
 238         unsigned long long count_reader[NR_READ], count_writer[NR_WRITE];
 239         unsigned long long tot_reads = 0, tot_writes = 0;
 240         int i;
 241
 242         if (argc < 2) {
 243                 show_usage(argc, argv);
 244                 return -1;
 245         }
 246
 247         err = sscanf(argv[1], "%lu", &duration);
 248         if (err != 1) {
 249                 show_usage(argc, argv);
 250                 return -1;
 251         }
 252
 253         for (i = 2; i < argc; i++) {
 254                 if (argv[i][0] != '-')
 255                         continue;
 256                 switch (argv[i][1]) {
 257 #ifdef DEBUG_YIELD
 258                 case 'r':
 259                         yield_active |= YIELD_READ;
 260                         break;
 261                 case 'w':
 262                         yield_active |= YIELD_WRITE;
 263                         break;
 264 #endif
 265                 case 'n':
 266                         no_writer_delay = 1;
 267                         break;
 268                 }
 269         }
 270
 271         printf("running test for %lu seconds.\n", duration);
 272         start_time = time(NULL);
 273         printf("thread %-6s, thread id : %lx, tid %lu\n",
 274                         "main", pthread_self(), (unsigned long)gettid());
 275
 276         for (i = 0; i < NR_READ; i++) {
 277                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 278                                      &count_reader[i]);
 279                 if (err != 0)
 280                         exit(1);
 281         }
 282         for (i = 0; i < NR_WRITE; i++) {
 283                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 284                                      &count_writer[i]);
 285                 if (err != 0)
 286                         exit(1);
 287         }
 288
 289         for (i = 0; i < NR_READ; i++) {
 290                 err = pthread_join(tid_reader[i], &tret);
 291                 if (err != 0)
 292                         exit(1);
 293                 tot_reads += count_reader[i];
 294         }
 295         for (i = 0; i < NR_WRITE; i++) {
 296                 err = pthread_join(tid_writer[i], &tret);
 297                 if (err != 0)
 298                         exit(1);
 299                 tot_writes += count_writer[i];
 300         }
 301
 302         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 303                tot_writes);
 304         test_array_free(test_rcu_pointer);
 305
 306         return 0;
 307 }