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 loops */
  73 static unsigned long rduration;
  74
  75 static inline void loop_sleep(unsigned long l)
  76 {
  77         while(l-- != 0)
  78                 cpu_relax();
  79 }
  80
  81 /*
  82  * returns 0 if test should end.
  83  */
  84 static int test_duration_write(void)
  85 {
  86         return !test_stop;
  87 }
  88
  89 static int test_duration_read(void)
  90 {
  91         return !test_stop;
  92 }
  93
  94 static unsigned long long __thread nr_writes;
  95 static unsigned long long __thread nr_reads;
  96
  97 static unsigned int nr_readers;
  98 static unsigned int nr_writers;
  99
 100 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
 101
 102 void rcu_copy_mutex_lock(void)
 103 {
 104         int ret;
 105         ret = pthread_mutex_lock(&rcu_copy_mutex);
 106         if (ret) {
 107                 perror("Error in pthread mutex lock");
 108                 exit(-1);
 109         }
 110 }
 111
 112 void rcu_copy_mutex_unlock(void)
 113 {
 114         int ret;
 115
 116         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 117         if (ret) {
 118                 perror("Error in pthread mutex unlock");
 119                 exit(-1);
 120         }
 121 }
 122
 123 /*
 124  * malloc/free are reusing memory areas too quickly, which does not let us
 125  * test races appropriately. Use a large circular array for allocations.
 126  * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 127  */
 128 #define ARRAY_SIZE (1048576 * nr_writers)
 129 #define ARRAY_POISON 0xDEADBEEF
 130 static int array_index;
 131 static struct test_array *test_array;
 132
 133 static struct test_array *test_array_alloc(void)
 134 {
 135         struct test_array *ret;
 136         int index;
 137
 138         rcu_copy_mutex_lock();
 139         index = array_index % ARRAY_SIZE;
 140         assert(test_array[index].a == ARRAY_POISON ||
 141                 test_array[index].a == 0);
 142         ret = &test_array[index];
 143         array_index++;
 144         if (array_index == ARRAY_SIZE)
 145                 array_index = 0;
 146         rcu_copy_mutex_unlock();
 147         return ret;
 148 }
 149
 150 static void test_array_free(struct test_array *ptr)
 151 {
 152         if (!ptr)
 153                 return;
 154         rcu_copy_mutex_lock();
 155         ptr->a = ARRAY_POISON;
 156         rcu_copy_mutex_unlock();
 157 }
 158
 159 void *thr_reader(void *_count)
 160 {
 161         unsigned long long *count = _count;
 162         struct test_array *local_ptr;
 163
 164         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 165                         "reader", pthread_self(), (unsigned long)gettid());
 166
 167         rcu_register_thread();
 168
 169         while (!test_go)
 170         {
 171         }
 172         smp_mb();
 173
 174         for (;;) {
 175                 rcu_read_lock();
 176                 local_ptr = rcu_dereference(test_rcu_pointer);
 177                 debug_yield_read();
 178                 if (local_ptr)
 179                         assert(local_ptr->a == 8);
 180                 if (unlikely(rduration))
 181                         loop_sleep(rduration);
 182                 rcu_read_unlock();
 183                 nr_reads++;
 184                 if (unlikely(!test_duration_read()))
 185                         break;
 186         }
 187
 188         rcu_unregister_thread();
 189
 190         *count = nr_reads;
 191         printf("thread_end %s, thread id : %lx, tid %lu\n",
 192                         "reader", pthread_self(), (unsigned long)gettid());
 193         return ((void*)1);
 194
 195 }
 196
 197 void *thr_writer(void *_count)
 198 {
 199         unsigned long long *count = _count;
 200         struct test_array *new, *old;
 201
 202         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 203                         "writer", pthread_self(), (unsigned long)gettid());
 204
 205         while (!test_go)
 206         {
 207         }
 208         smp_mb();
 209
 210         for (;;) {
 211                 new = test_array_alloc();
 212                 rcu_copy_mutex_lock();
 213                 old = test_rcu_pointer;
 214                 if (old)
 215                         assert(old->a == 8);
 216                 new->a = 8;
 217                 old = rcu_publish_content(&test_rcu_pointer, new);
 218                 rcu_copy_mutex_unlock();
 219                 /* can be done after unlock */
 220                 if (old)
 221                         old->a = 0;
 222                 test_array_free(old);
 223                 nr_writes++;
 224                 if (unlikely(!test_duration_write()))
 225                         break;
 226                 if (unlikely(wdelay))
 227                         usleep(wdelay);
 228         }
 229
 230         printf("thread_end %s, thread id : %lx, tid %lu\n",
 231                         "writer", pthread_self(), (unsigned long)gettid());
 232         *count = nr_writes;
 233         return ((void*)2);
 234 }
 235
 236 void show_usage(int argc, char **argv)
 237 {
 238         printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
 239 #ifdef DEBUG_YIELD
 240         printf(" [-r] [-w] (yield reader and/or writer)");
 241 #endif
 242         printf(" [-d delay] (writer period (us))");
 243         printf(" [-c duration] (reader C.S. duration (in loops))");
 244         printf(" [-a cpu#] [-a cpu#]... (affinity)");
 245         printf("\n");
 246 }
 247
 248 cpu_set_t affinity;
 249
 250 int main(int argc, char **argv)
 251 {
 252         int err;
 253         pthread_t *tid_reader, *tid_writer;
 254         void *tret;
 255         unsigned long long *count_reader, *count_writer;
 256         unsigned long long tot_reads = 0, tot_writes = 0;
 257         int i, a;
 258         int use_affinity = 0;
 259
 260         if (argc < 4) {
 261                 show_usage(argc, argv);
 262                 return -1;
 263         }
 264
 265         err = sscanf(argv[1], "%u", &nr_readers);
 266         if (err != 1) {
 267                 show_usage(argc, argv);
 268                 return -1;
 269         }
 270
 271         err = sscanf(argv[2], "%u", &nr_writers);
 272         if (err != 1) {
 273                 show_usage(argc, argv);
 274                 return -1;
 275         }
 276
 277         err = sscanf(argv[3], "%lu", &duration);
 278         if (err != 1) {
 279                 show_usage(argc, argv);
 280                 return -1;
 281         }
 282
 283         CPU_ZERO(&affinity);
 284
 285         for (i = 4; i < argc; i++) {
 286                 if (argv[i][0] != '-')
 287                         continue;
 288                 switch (argv[i][1]) {
 289 #ifdef DEBUG_YIELD
 290                 case 'r':
 291                         yield_active |= YIELD_READ;
 292                         break;
 293                 case 'w':
 294                         yield_active |= YIELD_WRITE;
 295                         break;
 296 #endif
 297                 case 'a':
 298                         if (argc < i + 2) {
 299                                 show_usage(argc, argv);
 300                                 return -1;
 301                         }
 302                         a = atoi(argv[++i]);
 303                         CPU_SET(a, &affinity);
 304                         use_affinity = 1;
 305                         printf("Adding CPU %d affinity\n", a);
 306                         break;
 307                 case 'c':
 308                         if (argc < i + 2) {
 309                                 show_usage(argc, argv);
 310                                 return -1;
 311                         }
 312                         rduration = atoi(argv[++i]);
 313                         break;
 314                 case 'd':
 315                         if (argc < i + 2) {
 316                                 show_usage(argc, argv);
 317                                 return -1;
 318                         }
 319                         wdelay = atoi(argv[++i]);
 320                         break;
 321                 }
 322         }
 323
 324         printf("running test for %lu seconds, %u readers, %u writers.\n",
 325                 duration, nr_readers, nr_writers);
 326         printf("Writer delay : %u us.\n", wdelay);
 327         printf("thread %-6s, thread id : %lx, tid %lu\n",
 328                         "main", pthread_self(), (unsigned long)gettid());
 329
 330         if (use_affinity
 331             && sched_setaffinity(0, sizeof(affinity), &affinity) < 0) {
 332                 perror("sched_setaffinity");
 333                 exit(-1);
 334         }
 335
 336         test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
 337         tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
 338         tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
 339         count_reader = malloc(sizeof(*count_reader) * nr_readers);
 340         count_writer = malloc(sizeof(*count_writer) * nr_writers);
 341
 342         for (i = 0; i < nr_readers; i++) {
 343                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 344                                      &count_reader[i]);
 345                 if (err != 0)
 346                         exit(1);
 347         }
 348         for (i = 0; i < nr_writers; i++) {
 349                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 350                                      &count_writer[i]);
 351                 if (err != 0)
 352                         exit(1);
 353         }
 354
 355         smp_mb();
 356
 357         test_go = 1;
 358
 359         sleep(duration);
 360
 361         test_stop = 1;
 362
 363         for (i = 0; i < nr_readers; i++) {
 364                 err = pthread_join(tid_reader[i], &tret);
 365                 if (err != 0)
 366                         exit(1);
 367                 tot_reads += count_reader[i];
 368         }
 369         for (i = 0; i < nr_writers; i++) {
 370                 err = pthread_join(tid_writer[i], &tret);
 371                 if (err != 0)
 372                         exit(1);
 373                 tot_writes += count_writer[i];
 374         }
 375
 376         printf("total number of reads : %llu, writes %llu\n", tot_reads,
 377                tot_writes);
 378         test_array_free(test_rcu_pointer);
 379         free(test_array);
 380         free(tid_reader);
 381         free(tid_writer);
 382         free(count_reader);
 383         free(count_writer);
 384         return 0;
 385 }