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_WRITE 4
  51 #define DURATION_TEST_DELAY_READ 100
  52
  53 /*
  54  * returns 0 if test should end.
  55  */
  56 static int test_duration_write(void)
  57 {
  58         if (duration_interval++ >= DURATION_TEST_DELAY_WRITE) {
  59                 duration_interval = 0;
  60                 if (time(NULL) - start_time >= duration)
  61                         return 0;
  62         }
  63         return 1;
  64 }
  65
  66 static int test_duration_read(void)
  67 {
  68         if (duration_interval++ >= DURATION_TEST_DELAY_READ) {
  69                 duration_interval = 0;
  70                 if (time(NULL) - start_time >= duration)
  71                         return 0;
  72         }
  73         return 1;
  74 }
  75
  76 #define NR_READ 10
  77 #define NR_WRITE 9
  78
  79 static unsigned long long __thread nr_writes;
  80 static unsigned long long __thread nr_reads;
  81
  82 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  83
  84 void rcu_copy_mutex_lock(void)
  85 {
  86         int ret;
  87         ret = pthread_mutex_lock(&rcu_copy_mutex);
  88         if (ret) {
  89                 perror("Error in pthread mutex lock");
  90                 exit(-1);
  91         }
  92 }
  93
  94 void rcu_copy_mutex_unlock(void)
  95 {
  96         int ret;
  97
  98         ret = pthread_mutex_unlock(&rcu_copy_mutex);
  99         if (ret) {
 100                 perror("Error in pthread mutex unlock");
 101                 exit(-1);
 102         }
 103 }
 104
 105 /*
 106  * malloc/free are reusing memory areas too quickly, which does not let us
 107  * test races appropriately. Use a large circular array for allocations.
 108  * ARRAY_SIZE is larger than NR_WRITE, which insures we never run over our tail.
 109  */
 110 #define ARRAY_SIZE (1048576 * NR_WRITE)
 111 #define ARRAY_POISON 0xDEADBEEF
 112 static int array_index;
 113 static struct test_array test_array[ARRAY_SIZE];
 114
 115 static struct test_array *test_array_alloc(void)
 116 {
 117         struct test_array *ret;
 118         int index;
 119
 120         rcu_copy_mutex_lock();
 121         index = array_index % ARRAY_SIZE;
 122         assert(test_array[index].a == ARRAY_POISON ||
 123                 test_array[index].a == 0);
 124         ret = &test_array[index];
 125         array_index++;
 126         if (array_index == ARRAY_SIZE)
 127                 array_index = 0;
 128         rcu_copy_mutex_unlock();
 129         return ret;
 130 }
 131
 132 static void test_array_free(struct test_array *ptr)
 133 {
 134         if (!ptr)
 135                 return;
 136         rcu_copy_mutex_lock();
 137         ptr->a = ARRAY_POISON;
 138         rcu_copy_mutex_unlock();
 139 }
 140
 141 void *thr_reader(void *_count)
 142 {
 143         unsigned long long *count = _count;
 144         struct test_array *local_ptr;
 145
 146         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 147                         "reader", pthread_self(), (unsigned long)gettid());
 148
 149         urcu_register_thread();
 150
 151         for (;;) {
 152                 rcu_read_lock();
 153                 local_ptr = rcu_dereference(test_rcu_pointer);
 154                 debug_yield_read();
 155                 if (local_ptr)
 156                         assert(local_ptr->a == 8);
 157                 rcu_read_unlock();
 158                 nr_reads++;
 159                 if (!test_duration_read())
 160                         break;
 161         }
 162
 163         urcu_unregister_thread();
 164
 165         *count = nr_reads;
 166         printf("thread_end %s, thread id : %lx, tid %lu\n",
 167                         "reader", pthread_self(), (unsigned long)gettid());
 168         return ((void*)1);
 169
 170 }
 171
 172 void *thr_writer(void *_count)
 173 {
 174         unsigned long long *count = _count;
 175         struct test_array *new, *old;
 176
 177         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 178                         "writer", pthread_self(), (unsigned long)gettid());
 179
 180         for (;;) {
 181                 new = test_array_alloc();
 182                 rcu_copy_mutex_lock();
 183                 old = test_rcu_pointer;
 184                 if (old)
 185                         assert(old->a == 8);
 186                 new->a = 8;
 187                 old = urcu_publish_content(&test_rcu_pointer, new);
 188                 rcu_copy_mutex_unlock();
 189                 /* can be done after unlock */
 190                 if (old)
 191                         old->a = 0;
 192                 test_array_free(old);
 193                 nr_writes++;
 194                 if (!test_duration_write())
 195                         break;
 196                 if (!no_writer_delay)
 197                         usleep(1);
 198         }
 199
 200         printf("thread_end %s, thread id : %lx, tid %lu\n",
 201                         "writer", pthread_self(), (unsigned long)gettid());
 202         *count = nr_writes;
 203         return ((void*)2);
 204 }
 205
 206 void show_usage(int argc, char **argv)
 207 {
 208         printf("Usage : %s duration (s)", argv[0]);
 209 #ifdef DEBUG_YIELD
 210         printf(" [-r] [-w] (yield reader and/or writer)");
 211 #endif
 212         printf(" [-n] (disable writer delay)");
 213         printf("\n");
 214 }
 215
 216 int main(int argc, char **argv)
 217 {
 218         int err;
 219         pthread_t tid_reader[NR_READ], tid_writer[NR_WRITE];
 220         void *tret;
 221         unsigned long long count_reader[NR_READ], count_writer[NR_WRITE];
 222         unsigned long long tot_reads = 0, tot_writes = 0;
 223         int i;
 224
 225         if (argc < 2) {
 226                 show_usage(argc, argv);
 227                 return -1;
 228         }
 229
 230         err = sscanf(argv[1], "%lu", &duration);
 231         if (err != 1) {
 232                 show_usage(argc, argv);
 233                 return -1;
 234         }
 235
 236         for (i = 2; i < argc; i++) {
 237                 if (argv[i][0] != '-')
 238                         continue;
 239                 switch (argv[i][1]) {
 240 #ifdef DEBUG_YIELD
 241                 case 'r':
 242                         yield_active |= YIELD_READ;
 243                         break;
 244                 case 'w':
 245                         yield_active |= YIELD_WRITE;
 246                         break;
 247 #endif
 248                 case 'n':
 249                         no_writer_delay = 1;
 250                         break;
 251                 }
 252         }
 253
 254         printf("running test for %lu seconds.\n", duration);
 255         start_time = time(NULL);
 256         printf("thread %-6s, thread id : %lx, tid %lu\n",
 257                         "main", pthread_self(), (unsigned long)gettid());
 258
 259         for (i = 0; i < NR_READ; i++) {
 260                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 261                                      &count_reader[i]);
 262                 if (err != 0)
 263                         exit(1);
 264         }
 265         for (i = 0; i < NR_WRITE; i++) {
 266                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 267                                      &count_writer[i]);
 268                 if (err != 0)
 269                         exit(1);
 270         }
 271
 272         for (i = 0; i < NR_READ; i++) {
 273                 err = pthread_join(tid_reader[i], &tret);
 274                 if (err != 0)
 275                         exit(1);
 276                 tot_reads += count_reader[i];
 277         }
 278         for (i = 0; i < NR_WRITE; i++) {
 279                 err = pthread_join(tid_writer[i], &tret);
 280                 if (err != 0)
 281                         exit(1);
 282                 tot_writes += count_writer[i];
 283         }
 284
 285         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 286                tot_writes);
 287         test_array_free(test_rcu_pointer);
 288
 289         return 0;
 290 }