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 static unsigned long long __thread nr_writes;
  69 static unsigned long long __thread nr_reads;
  70
  71 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  72
  73 void rcu_copy_mutex_lock(void)
  74 {
  75         int ret;
  76         ret = pthread_mutex_lock(&rcu_copy_mutex);
  77         if (ret) {
  78                 perror("Error in pthread mutex lock");
  79                 exit(-1);
  80         }
  81 }
  82
  83 void rcu_copy_mutex_unlock(void)
  84 {
  85         int ret;
  86
  87         ret = pthread_mutex_unlock(&rcu_copy_mutex);
  88         if (ret) {
  89                 perror("Error in pthread mutex unlock");
  90                 exit(-1);
  91         }
  92 }
  93
  94 /*
  95  * malloc/free are reusing memory areas too quickly, which does not let us
  96  * test races appropriately. Use a large circular array for allocations.
  97  * ARRAY_SIZE is larger than NR_WRITE, which insures we never run over our tail.
  98  */
  99 #define ARRAY_SIZE (1048576 * NR_WRITE)
 100 #define ARRAY_POISON 0xDEADBEEF
 101 static int array_index;
 102 static struct test_array test_array[ARRAY_SIZE];
 103
 104 static struct test_array *test_array_alloc(void)
 105 {
 106         struct test_array *ret;
 107         int index;
 108
 109         rcu_copy_mutex_lock();
 110         index = array_index % ARRAY_SIZE;
 111         assert(test_array[index].a == ARRAY_POISON ||
 112                 test_array[index].a == 0);
 113         ret = &test_array[index];
 114         array_index++;
 115         if (array_index == ARRAY_SIZE)
 116                 array_index = 0;
 117         rcu_copy_mutex_unlock();
 118         return ret;
 119 }
 120
 121 static void test_array_free(struct test_array *ptr)
 122 {
 123         if (!ptr)
 124                 return;
 125         rcu_copy_mutex_lock();
 126         ptr->a = ARRAY_POISON;
 127         rcu_copy_mutex_unlock();
 128 }
 129
 130 void *thr_reader(void *_count)
 131 {
 132         unsigned long long *count = _count;
 133         struct test_array *local_ptr;
 134
 135         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 136                         "reader", pthread_self(), (unsigned long)gettid());
 137
 138         urcu_register_thread();
 139
 140         for (;;) {
 141                 rcu_read_lock();
 142                 local_ptr = rcu_dereference(test_rcu_pointer);
 143                 debug_yield_read();
 144                 if (local_ptr)
 145                         assert(local_ptr->a == 8);
 146                 rcu_read_unlock();
 147                 nr_reads++;
 148                 if (!test_duration())
 149                         break;
 150         }
 151
 152         urcu_unregister_thread();
 153
 154         *count = nr_reads;
 155         printf("thread_end %s, thread id : %lx, tid %lu\n",
 156                         "reader", pthread_self(), (unsigned long)gettid());
 157         return ((void*)1);
 158
 159 }
 160
 161 void *thr_writer(void *_count)
 162 {
 163         unsigned long long *count = _count;
 164         struct test_array *new, *old;
 165
 166         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 167                         "writer", pthread_self(), (unsigned long)gettid());
 168
 169         for (;;) {
 170                 new = test_array_alloc();
 171                 rcu_copy_mutex_lock();
 172                 old = test_rcu_pointer;
 173                 if (old)
 174                         assert(old->a == 8);
 175                 new->a = 8;
 176                 old = urcu_publish_content(&test_rcu_pointer, new);
 177                 rcu_copy_mutex_unlock();
 178                 /* can be done after unlock */
 179                 if (old)
 180                         old->a = 0;
 181                 test_array_free(old);
 182                 nr_writes++;
 183                 if (!test_duration())
 184                         break;
 185                 if (!no_writer_delay)
 186                         usleep(1);
 187         }
 188
 189         printf("thread_end %s, thread id : %lx, tid %lu\n",
 190                         "writer", pthread_self(), (unsigned long)gettid());
 191         *count = nr_writes;
 192         return ((void*)2);
 193 }
 194
 195 void show_usage(int argc, char **argv)
 196 {
 197         printf("Usage : %s duration (s)", argv[0]);
 198 #ifdef DEBUG_YIELD
 199         printf(" [-r] [-w] (yield reader and/or writer)");
 200 #endif
 201         printf(" [-n] (disable writer delay)");
 202         printf("\n");
 203 }
 204
 205 int main(int argc, char **argv)
 206 {
 207         int err;
 208         pthread_t tid_reader[NR_READ], tid_writer[NR_WRITE];
 209         void *tret;
 210         unsigned long long count_reader[NR_READ], count_writer[NR_WRITE];
 211         unsigned long long tot_reads = 0, tot_writes = 0;
 212         int i;
 213
 214         if (argc < 2) {
 215                 show_usage(argc, argv);
 216                 return -1;
 217         }
 218
 219         err = sscanf(argv[1], "%lu", &duration);
 220         if (err != 1) {
 221                 show_usage(argc, argv);
 222                 return -1;
 223         }
 224
 225         for (i = 2; i < argc; i++) {
 226                 if (argv[i][0] != '-')
 227                         continue;
 228                 switch (argv[i][1]) {
 229 #ifdef DEBUG_YIELD
 230                 case 'r':
 231                         yield_active |= YIELD_READ;
 232                         break;
 233                 case 'w':
 234                         yield_active |= YIELD_WRITE;
 235                         break;
 236 #endif
 237                 case 'n':
 238                         no_writer_delay = 1;
 239                         break;
 240                 }
 241         }
 242
 243         printf("running test for %lu seconds.\n", duration);
 244         start_time = time(NULL);
 245         printf("thread %-6s, thread id : %lx, tid %lu\n",
 246                         "main", pthread_self(), (unsigned long)gettid());
 247
 248         for (i = 0; i < NR_READ; i++) {
 249                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 250                                      &count_reader[i]);
 251                 if (err != 0)
 252                         exit(1);
 253         }
 254         for (i = 0; i < NR_WRITE; i++) {
 255                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 256                                      &count_writer[i]);
 257                 if (err != 0)
 258                         exit(1);
 259         }
 260
 261         for (i = 0; i < NR_READ; i++) {
 262                 err = pthread_join(tid_reader[i], &tret);
 263                 if (err != 0)
 264                         exit(1);
 265                 tot_reads += count_reader[i];
 266         }
 267         for (i = 0; i < NR_WRITE; i++) {
 268                 err = pthread_join(tid_writer[i], &tret);
 269                 if (err != 0)
 270                         exit(1);
 271                 tot_writes += count_writer[i];
 272         }
 273         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 274                tot_writes);
 275         test_array_free(test_rcu_pointer);
 276
 277         return 0;
 278 }