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 #define _GNU_SOURCE
  24 #include <stdio.h>
  25 #include <pthread.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/types.h>
  29 #include <sys/wait.h>
  30 #include <unistd.h>
  31 #include <stdio.h>
  32 #include <assert.h>
  33 #include <sys/syscall.h>
  34 #include <sched.h>
  35
  36 #include "arch.h"
  37
  38 #if defined(_syscall0)
  39 _syscall0(pid_t, gettid)
  40 #elif defined(__NR_gettid)
  41 static inline pid_t gettid(void)
  42 {
  43         return syscall(__NR_gettid);
  44 }
  45 #else
  46 #warning "use pid as tid"
  47 static inline pid_t gettid(void)
  48 {
  49         return getpid();
  50 }
  51 #endif
  52
  53 #ifndef DYNAMIC_LINK_TEST
  54 #define _LGPL_SOURCE
  55 #else
  56 #define debug_yield_read()
  57 #endif
  58 #include "urcu.h"
  59
  60 struct test_array {
  61         int a;
  62 };
  63
  64 static volatile int test_go, test_stop;
  65
  66 static int wdelay;
  67
  68 static struct test_array *test_rcu_pointer;
  69
  70 static unsigned long duration;
  71
  72 /*
  73  * returns 0 if test should end.
  74  */
  75 static int test_duration_write(void)
  76 {
  77         return !test_stop;
  78 }
  79
  80 static int test_duration_read(void)
  81 {
  82         return !test_stop;
  83 }
  84
  85 static unsigned long long __thread nr_writes;
  86 static unsigned long long __thread nr_reads;
  87
  88 static unsigned int nr_readers;
  89 static unsigned int nr_writers;
  90
  91 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  92
  93 void rcu_copy_mutex_lock(void)
  94 {
  95         int ret;
  96         ret = pthread_mutex_lock(&rcu_copy_mutex);
  97         if (ret) {
  98                 perror("Error in pthread mutex lock");
  99                 exit(-1);
 100         }
 101 }
 102
 103 void rcu_copy_mutex_unlock(void)
 104 {
 105         int ret;
 106
 107         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 108         if (ret) {
 109                 perror("Error in pthread mutex unlock");
 110                 exit(-1);
 111         }
 112 }
 113
 114 /*
 115  * malloc/free are reusing memory areas too quickly, which does not let us
 116  * test races appropriately. Use a large circular array for allocations.
 117  * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 118  */
 119 #define ARRAY_SIZE (1048576 * nr_writers)
 120 #define ARRAY_POISON 0xDEADBEEF
 121 static int array_index;
 122 static struct test_array *test_array;
 123
 124 static struct test_array *test_array_alloc(void)
 125 {
 126         struct test_array *ret;
 127         int index;
 128
 129         rcu_copy_mutex_lock();
 130         index = array_index % ARRAY_SIZE;
 131         assert(test_array[index].a == ARRAY_POISON ||
 132                 test_array[index].a == 0);
 133         ret = &test_array[index];
 134         array_index++;
 135         if (array_index == ARRAY_SIZE)
 136                 array_index = 0;
 137         rcu_copy_mutex_unlock();
 138         return ret;
 139 }
 140
 141 static void test_array_free(struct test_array *ptr)
 142 {
 143         if (!ptr)
 144                 return;
 145         rcu_copy_mutex_lock();
 146         ptr->a = ARRAY_POISON;
 147         rcu_copy_mutex_unlock();
 148 }
 149
 150 void *thr_reader(void *_count)
 151 {
 152         unsigned long long *count = _count;
 153         struct test_array *local_ptr;
 154
 155         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 156                         "reader", pthread_self(), (unsigned long)gettid());
 157
 158         rcu_register_thread();
 159
 160         while (!test_go)
 161         {
 162         }
 163         smp_mb();
 164
 165         for (;;) {
 166                 rcu_read_lock();
 167                 local_ptr = rcu_dereference(test_rcu_pointer);
 168                 debug_yield_read();
 169                 if (local_ptr)
 170                         assert(local_ptr->a == 8);
 171                 rcu_read_unlock();
 172                 nr_reads++;
 173                 if (unlikely(!test_duration_read()))
 174                         break;
 175         }
 176
 177         rcu_unregister_thread();
 178
 179         *count = nr_reads;
 180         printf("thread_end %s, thread id : %lx, tid %lu\n",
 181                         "reader", pthread_self(), (unsigned long)gettid());
 182         return ((void*)1);
 183
 184 }
 185
 186 void *thr_writer(void *_count)
 187 {
 188         unsigned long long *count = _count;
 189         struct test_array *new, *old;
 190
 191         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 192                         "writer", pthread_self(), (unsigned long)gettid());
 193
 194         while (!test_go)
 195         {
 196         }
 197         smp_mb();
 198
 199         for (;;) {
 200                 new = test_array_alloc();
 201                 rcu_copy_mutex_lock();
 202                 old = test_rcu_pointer;
 203                 if (old)
 204                         assert(old->a == 8);
 205                 new->a = 8;
 206                 old = rcu_publish_content(&test_rcu_pointer, new);
 207                 rcu_copy_mutex_unlock();
 208                 /* can be done after unlock */
 209                 if (old)
 210                         old->a = 0;
 211                 test_array_free(old);
 212                 nr_writes++;
 213                 if (unlikely(!test_duration_write()))
 214                         break;
 215                 if (unlikely(wdelay))
 216                         usleep(wdelay);
 217         }
 218
 219         printf("thread_end %s, thread id : %lx, tid %lu\n",
 220                         "writer", pthread_self(), (unsigned long)gettid());
 221         *count = nr_writes;
 222         return ((void*)2);
 223 }
 224
 225 void show_usage(int argc, char **argv)
 226 {
 227         printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
 228 #ifdef DEBUG_YIELD
 229         printf(" [-r] [-w] (yield reader and/or writer)");
 230 #endif
 231         printf(" [-d delay] (writer period (us))");
 232         printf(" [-a cpu#] [-a cpu#]... (affinity)");
 233         printf("\n");
 234 }
 235
 236 cpu_set_t affinity;
 237
 238 int main(int argc, char **argv)
 239 {
 240         int err;
 241         pthread_t *tid_reader, *tid_writer;
 242         void *tret;
 243         unsigned long long *count_reader, *count_writer;
 244         unsigned long long tot_reads = 0, tot_writes = 0;
 245         int i, a;
 246         int use_affinity = 0;
 247
 248         if (argc < 4) {
 249                 show_usage(argc, argv);
 250                 return -1;
 251         }
 252
 253         err = sscanf(argv[1], "%u", &nr_readers);
 254         if (err != 1) {
 255                 show_usage(argc, argv);
 256                 return -1;
 257         }
 258
 259         err = sscanf(argv[2], "%u", &nr_writers);
 260         if (err != 1) {
 261                 show_usage(argc, argv);
 262                 return -1;
 263         }
 264
 265         err = sscanf(argv[3], "%lu", &duration);
 266         if (err != 1) {
 267                 show_usage(argc, argv);
 268                 return -1;
 269         }
 270
 271         CPU_ZERO(&affinity);
 272
 273         for (i = 4; i < argc; i++) {
 274                 if (argv[i][0] != '-')
 275                         continue;
 276                 switch (argv[i][1]) {
 277 #ifdef DEBUG_YIELD
 278                 case 'r':
 279                         yield_active |= YIELD_READ;
 280                         break;
 281                 case 'w':
 282                         yield_active |= YIELD_WRITE;
 283                         break;
 284 #endif
 285                 case 'a':
 286                         if (argc < i + 2) {
 287                                 show_usage(argc, argv);
 288                                 return -1;
 289                         }
 290                         a = atoi(argv[++i]);
 291                         CPU_SET(a, &affinity);
 292                         use_affinity = 1;
 293                         printf("Adding CPU %d affinity\n", a);
 294                         break;
 295                 case 'd':
 296                         if (argc < i + 2) {
 297                                 show_usage(argc, argv);
 298                                 return -1;
 299                         }
 300                         wdelay = atoi(argv[++i]);
 301                         break;
 302                 }
 303         }
 304
 305         printf("running test for %lu seconds, %u readers, %u writers.\n",
 306                 duration, nr_readers, nr_writers);
 307         printf("Writer delay : %u us.\n", wdelay);
 308         printf("thread %-6s, thread id : %lx, tid %lu\n",
 309                         "main", pthread_self(), (unsigned long)gettid());
 310
 311         if (use_affinity
 312             && sched_setaffinity(0, sizeof(affinity), &affinity) < 0) {
 313                 perror("sched_setaffinity");
 314                 exit(-1);
 315         }
 316
 317         test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
 318         tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
 319         tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
 320         count_reader = malloc(sizeof(*count_reader) * nr_readers);
 321         count_writer = malloc(sizeof(*count_writer) * nr_writers);
 322
 323         for (i = 0; i < nr_readers; i++) {
 324                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 325                                      &count_reader[i]);
 326                 if (err != 0)
 327                         exit(1);
 328         }
 329         for (i = 0; i < nr_writers; i++) {
 330                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 331                                      &count_writer[i]);
 332                 if (err != 0)
 333                         exit(1);
 334         }
 335
 336         smp_mb();
 337
 338         test_go = 1;
 339
 340         sleep(duration);
 341
 342         test_stop = 1;
 343
 344         for (i = 0; i < nr_readers; i++) {
 345                 err = pthread_join(tid_reader[i], &tret);
 346                 if (err != 0)
 347                         exit(1);
 348                 tot_reads += count_reader[i];
 349         }
 350         for (i = 0; i < nr_writers; i++) {
 351                 err = pthread_join(tid_writer[i], &tret);
 352                 if (err != 0)
 353                         exit(1);
 354                 tot_writes += count_writer[i];
 355         }
 356
 357         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 358                tot_writes);
 359         test_array_free(test_rcu_pointer);
 360         free(test_array);
 361         free(tid_reader);
 362         free(tid_writer);
 363         free(count_reader);
 364         free(count_writer);
 365         return 0;
 366 }