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 /* read-side C.S. duration, in us */
  73 static unsigned long rduration;
  74
  75 /*
  76  * returns 0 if test should end.
  77  */
  78 static int test_duration_write(void)
  79 {
  80         return !test_stop;
  81 }
  82
  83 static int test_duration_read(void)
  84 {
  85         return !test_stop;
  86 }
  87
  88 static unsigned long long __thread nr_writes;
  89 static unsigned long long __thread nr_reads;
  90
  91 static unsigned int nr_readers;
  92 static unsigned int nr_writers;
  93
  94 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  95
  96 void rcu_copy_mutex_lock(void)
  97 {
  98         int ret;
  99         ret = pthread_mutex_lock(&rcu_copy_mutex);
 100         if (ret) {
 101                 perror("Error in pthread mutex lock");
 102                 exit(-1);
 103         }
 104 }
 105
 106 void rcu_copy_mutex_unlock(void)
 107 {
 108         int ret;
 109
 110         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 111         if (ret) {
 112                 perror("Error in pthread mutex unlock");
 113                 exit(-1);
 114         }
 115 }
 116
 117 /*
 118  * malloc/free are reusing memory areas too quickly, which does not let us
 119  * test races appropriately. Use a large circular array for allocations.
 120  * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 121  */
 122 #define ARRAY_SIZE (1048576 * nr_writers)
 123 #define ARRAY_POISON 0xDEADBEEF
 124 static int array_index;
 125 static struct test_array *test_array;
 126
 127 static struct test_array *test_array_alloc(void)
 128 {
 129         struct test_array *ret;
 130         int index;
 131
 132         rcu_copy_mutex_lock();
 133         index = array_index % ARRAY_SIZE;
 134         assert(test_array[index].a == ARRAY_POISON ||
 135                 test_array[index].a == 0);
 136         ret = &test_array[index];
 137         array_index++;
 138         if (array_index == ARRAY_SIZE)
 139                 array_index = 0;
 140         rcu_copy_mutex_unlock();
 141         return ret;
 142 }
 143
 144 static void test_array_free(struct test_array *ptr)
 145 {
 146         if (!ptr)
 147                 return;
 148         rcu_copy_mutex_lock();
 149         ptr->a = ARRAY_POISON;
 150         rcu_copy_mutex_unlock();
 151 }
 152
 153 void *thr_reader(void *_count)
 154 {
 155         unsigned long long *count = _count;
 156         struct test_array *local_ptr;
 157
 158         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 159                         "reader", pthread_self(), (unsigned long)gettid());
 160
 161         rcu_register_thread();
 162
 163         while (!test_go)
 164         {
 165         }
 166         smp_mb();
 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                 if (unlikely(rduration))
 175                         usleep(rduration);
 176                 rcu_read_unlock();
 177                 nr_reads++;
 178                 if (unlikely(!test_duration_read()))
 179                         break;
 180         }
 181
 182         rcu_unregister_thread();
 183
 184         *count = nr_reads;
 185         printf("thread_end %s, thread id : %lx, tid %lu\n",
 186                         "reader", pthread_self(), (unsigned long)gettid());
 187         return ((void*)1);
 188
 189 }
 190
 191 void *thr_writer(void *_count)
 192 {
 193         unsigned long long *count = _count;
 194         struct test_array *new, *old;
 195
 196         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 197                         "writer", pthread_self(), (unsigned long)gettid());
 198
 199         while (!test_go)
 200         {
 201         }
 202         smp_mb();
 203
 204         for (;;) {
 205                 new = test_array_alloc();
 206                 rcu_copy_mutex_lock();
 207                 old = test_rcu_pointer;
 208                 if (old)
 209                         assert(old->a == 8);
 210                 new->a = 8;
 211                 old = rcu_publish_content(&test_rcu_pointer, new);
 212                 rcu_copy_mutex_unlock();
 213                 /* can be done after unlock */
 214                 if (old)
 215                         old->a = 0;
 216                 test_array_free(old);
 217                 nr_writes++;
 218                 if (unlikely(!test_duration_write()))
 219                         break;
 220                 if (unlikely(wdelay))
 221                         usleep(wdelay);
 222         }
 223
 224         printf("thread_end %s, thread id : %lx, tid %lu\n",
 225                         "writer", pthread_self(), (unsigned long)gettid());
 226         *count = nr_writes;
 227         return ((void*)2);
 228 }
 229
 230 void show_usage(int argc, char **argv)
 231 {
 232         printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
 233 #ifdef DEBUG_YIELD
 234         printf(" [-r] [-w] (yield reader and/or writer)");
 235 #endif
 236         printf(" [-d delay] (writer period (us))");
 237         printf(" [-c duration] (reader C.S. duration (us))");
 238         printf(" [-a cpu#] [-a cpu#]... (affinity)");
 239         printf("\n");
 240 }
 241
 242 cpu_set_t affinity;
 243
 244 int main(int argc, char **argv)
 245 {
 246         int err;
 247         pthread_t *tid_reader, *tid_writer;
 248         void *tret;
 249         unsigned long long *count_reader, *count_writer;
 250         unsigned long long tot_reads = 0, tot_writes = 0;
 251         int i, a;
 252         int use_affinity = 0;
 253
 254         if (argc < 4) {
 255                 show_usage(argc, argv);
 256                 return -1;
 257         }
 258
 259         err = sscanf(argv[1], "%u", &nr_readers);
 260         if (err != 1) {
 261                 show_usage(argc, argv);
 262                 return -1;
 263         }
 264
 265         err = sscanf(argv[2], "%u", &nr_writers);
 266         if (err != 1) {
 267                 show_usage(argc, argv);
 268                 return -1;
 269         }
 270
 271         err = sscanf(argv[3], "%lu", &duration);
 272         if (err != 1) {
 273                 show_usage(argc, argv);
 274                 return -1;
 275         }
 276
 277         CPU_ZERO(&affinity);
 278
 279         for (i = 4; i < argc; i++) {
 280                 if (argv[i][0] != '-')
 281                         continue;
 282                 switch (argv[i][1]) {
 283 #ifdef DEBUG_YIELD
 284                 case 'r':
 285                         yield_active |= YIELD_READ;
 286                         break;
 287                 case 'w':
 288                         yield_active |= YIELD_WRITE;
 289                         break;
 290 #endif
 291                 case 'a':
 292                         if (argc < i + 2) {
 293                                 show_usage(argc, argv);
 294                                 return -1;
 295                         }
 296                         a = atoi(argv[++i]);
 297                         CPU_SET(a, &affinity);
 298                         use_affinity = 1;
 299                         printf("Adding CPU %d affinity\n", a);
 300                         break;
 301                 case 'c':
 302                         if (argc < i + 2) {
 303                                 show_usage(argc, argv);
 304                                 return -1;
 305                         }
 306                         rduration = atoi(argv[++i]);
 307                         break;
 308                 case 'd':
 309                         if (argc < i + 2) {
 310                                 show_usage(argc, argv);
 311                                 return -1;
 312                         }
 313                         wdelay = atoi(argv[++i]);
 314                         break;
 315                 }
 316         }
 317
 318         printf("running test for %lu seconds, %u readers, %u writers.\n",
 319                 duration, nr_readers, nr_writers);
 320         printf("Writer delay : %u us.\n", wdelay);
 321         printf("thread %-6s, thread id : %lx, tid %lu\n",
 322                         "main", pthread_self(), (unsigned long)gettid());
 323
 324         if (use_affinity
 325             && sched_setaffinity(0, sizeof(affinity), &affinity) < 0) {
 326                 perror("sched_setaffinity");
 327                 exit(-1);
 328         }
 329
 330         test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
 331         tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
 332         tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
 333         count_reader = malloc(sizeof(*count_reader) * nr_readers);
 334         count_writer = malloc(sizeof(*count_writer) * nr_writers);
 335
 336         for (i = 0; i < nr_readers; i++) {
 337                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 338                                      &count_reader[i]);
 339                 if (err != 0)
 340                         exit(1);
 341         }
 342         for (i = 0; i < nr_writers; i++) {
 343                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 344                                      &count_writer[i]);
 345                 if (err != 0)
 346                         exit(1);
 347         }
 348
 349         smp_mb();
 350
 351         test_go = 1;
 352
 353         sleep(duration);
 354
 355         test_stop = 1;
 356
 357         for (i = 0; i < nr_readers; i++) {
 358                 err = pthread_join(tid_reader[i], &tret);
 359                 if (err != 0)
 360                         exit(1);
 361                 tot_reads += count_reader[i];
 362         }
 363         for (i = 0; i < nr_writers; i++) {
 364                 err = pthread_join(tid_writer[i], &tret);
 365                 if (err != 0)
 366                         exit(1);
 367                 tot_writes += count_writer[i];
 368         }
 369
 370         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 371                tot_writes);
 372         test_array_free(test_rcu_pointer);
 373         free(test_array);
 374         free(tid_reader);
 375         free(tid_writer);
 376         free(count_reader);
 377         free(count_writer);
 378         return 0;
 379 }