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  * Distributed under GPLv2
   9  */
  10
  11 #include <stdio.h>
  12 #include <pthread.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/types.h>
  16 #include <sys/wait.h>
  17 #include <unistd.h>
  18 #include <stdio.h>
  19 #include <assert.h>
  20 #include <sys/syscall.h>
  21
  22 #if defined(_syscall0)
  23 _syscall0(pid_t, gettid)
  24 #elif defined(__NR_gettid)
  25 static inline pid_t gettid(void)
  26 {
  27         return syscall(__NR_gettid);
  28 }
  29 #else
  30 #warning "use pid as tid"
  31 static inline pid_t gettid(void)
  32 {
  33         return getpid();
  34 }
  35 #endif
  36
  37 #include "urcu.h"
  38
  39 struct test_array {
  40         int a;
  41 };
  42
  43 static int no_writer_delay;
  44
  45 static struct test_array *test_rcu_pointer;
  46
  47 static unsigned long duration;
  48 static time_t start_time;
  49 static unsigned long __thread duration_interval;
  50 #define DURATION_TEST_DELAY 100
  51
  52 /*
  53  * returns 0 if test should end.
  54  */
  55 static int test_duration(void)
  56 {
  57         if (duration_interval++ >= DURATION_TEST_DELAY) {
  58                 duration_interval = 0;
  59                 if (time(NULL) - start_time >= duration)
  60                         return 0;
  61         }
  62         return 1;
  63 }
  64
  65 #define NR_READ 10
  66 #define NR_WRITE 9
  67
  68 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  69
  70 void rcu_copy_mutex_lock(void)
  71 {
  72         int ret;
  73         ret = pthread_mutex_lock(&rcu_copy_mutex);
  74         if (ret) {
  75                 perror("Error in pthread mutex lock");
  76                 exit(-1);
  77         }
  78 }
  79
  80 void rcu_copy_mutex_unlock(void)
  81 {
  82         int ret;
  83
  84         ret = pthread_mutex_unlock(&rcu_copy_mutex);
  85         if (ret) {
  86                 perror("Error in pthread mutex unlock");
  87                 exit(-1);
  88         }
  89 }
  90
  91 /*
  92  * malloc/free are reusing memory areas too quickly, which does not let us
  93  * test races appropriately. Use a large circular array for allocations.
  94  * ARRAY_SIZE is larger than NR_WRITE, which insures we never run over our tail.
  95  */
  96 #define ARRAY_SIZE (1048576 * NR_WRITE)
  97 #define ARRAY_POISON 0xDEADBEEF
  98 static int array_index;
  99 static struct test_array test_array[ARRAY_SIZE];
 100
 101 static struct test_array *test_array_alloc(void)
 102 {
 103         struct test_array *ret;
 104         int index;
 105
 106         rcu_copy_mutex_lock();
 107         index = array_index % ARRAY_SIZE;
 108         assert(test_array[index].a == ARRAY_POISON ||
 109                 test_array[index].a == 0);
 110         ret = &test_array[index];
 111         array_index++;
 112         if (array_index == ARRAY_SIZE)
 113                 array_index = 0;
 114         rcu_copy_mutex_unlock();
 115         return ret;
 116 }
 117
 118 static void test_array_free(struct test_array *ptr)
 119 {
 120         if (!ptr)
 121                 return;
 122         rcu_copy_mutex_lock();
 123         ptr->a = ARRAY_POISON;
 124         rcu_copy_mutex_unlock();
 125 }
 126
 127 void *thr_reader(void *arg)
 128 {
 129         struct test_array *local_ptr;
 130
 131         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 132                         "reader", pthread_self(), (unsigned long)gettid());
 133
 134         urcu_register_thread();
 135
 136         for (;;) {
 137                 rcu_read_lock();
 138                 local_ptr = rcu_dereference(test_rcu_pointer);
 139                 debug_yield_read();
 140                 if (local_ptr)
 141                         assert(local_ptr->a == 8);
 142                 rcu_read_unlock();
 143                 if (!test_duration())
 144                         break;
 145         }
 146
 147         urcu_unregister_thread();
 148
 149         printf("thread_end %s, thread id : %lx, tid %lu\n",
 150                         "reader", pthread_self(), (unsigned long)gettid());
 151         return ((void*)1);
 152
 153 }
 154
 155 void *thr_writer(void *arg)
 156 {
 157         struct test_array *new, *old;
 158
 159         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 160                         "writer", pthread_self(), (unsigned long)gettid());
 161
 162         for (;;) {
 163                 new = test_array_alloc();
 164                 rcu_copy_mutex_lock();
 165                 old = test_rcu_pointer;
 166                 if (old)
 167                         assert(old->a == 8);
 168                 new->a = 8;
 169                 old = urcu_publish_content(&test_rcu_pointer, new);
 170                 rcu_copy_mutex_unlock();
 171                 /* can be done after unlock */
 172                 if (old)
 173                         old->a = 0;
 174                 test_array_free(old);
 175                 if (!test_duration())
 176                         break;
 177                 if (!no_writer_delay)
 178                         usleep(1);
 179         }
 180
 181         printf("thread_end %s, thread id : %lx, tid %lu\n",
 182                         "writer", pthread_self(), (unsigned long)gettid());
 183         return ((void*)2);
 184 }
 185
 186 void show_usage(int argc, char **argv)
 187 {
 188         printf("Usage : %s duration (s)", argv[0]);
 189 #ifdef DEBUG_YIELD
 190         printf(" [-r] [-w] (yield reader and/or writer)");
 191 #endif
 192         printf(" [-n] (disable writer delay)");
 193         printf("\n");
 194 }
 195
 196 int main(int argc, char **argv)
 197 {
 198         int err;
 199         pthread_t tid_reader[NR_READ], tid_writer[NR_WRITE];
 200         void *tret;
 201         int i;
 202
 203         if (argc < 2) {
 204                 show_usage(argc, argv);
 205                 return -1;
 206         }
 207
 208         err = sscanf(argv[1], "%lu", &duration);
 209         if (err != 1) {
 210                 show_usage(argc, argv);
 211                 return -1;
 212         }
 213
 214         for (i = 2; i < argc; i++) {
 215                 if (argv[i][0] != '-')
 216                         continue;
 217                 switch (argv[i][1]) {
 218 #ifdef DEBUG_YIELD
 219                 case 'r':
 220                         yield_active |= YIELD_READ;
 221                         break;
 222                 case 'w':
 223                         yield_active |= YIELD_WRITE;
 224                         break;
 225 #endif
 226                 case 'n':
 227                         no_writer_delay = 1;
 228                         break;
 229                 }
 230         }
 231
 232         printf("running test for %lu seconds.\n", duration);
 233         start_time = time(NULL);
 234         printf("thread %-6s, thread id : %lx, tid %lu\n",
 235                         "main", pthread_self(), (unsigned long)gettid());
 236
 237         for (i = 0; i < NR_READ; i++) {
 238                 err = pthread_create(&tid_reader[i], NULL, thr_reader, NULL);
 239                 if (err != 0)
 240                         exit(1);
 241         }
 242         for (i = 0; i < NR_WRITE; i++) {
 243                 err = pthread_create(&tid_writer[i], NULL, thr_writer, NULL);
 244                 if (err != 0)
 245                         exit(1);
 246         }
 247
 248         for (i = 0; i < NR_READ; i++) {
 249                 err = pthread_join(tid_reader[i], &tret);
 250                 if (err != 0)
 251                         exit(1);
 252         }
 253         for (i = 0; i < NR_WRITE; i++) {
 254                 err = pthread_join(tid_writer[i], &tret);
 255                 if (err != 0)
 256                         exit(1);
 257         }
 258         test_array_free(test_rcu_pointer);
 259
 260         return 0;
 261 }