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 static int verbose_mode;
  82
  83 #define printf_verbose(fmt, args...)            \
  84         do {                                    \
  85                 if (verbose_mode)               \
  86                         printf(fmt, args);      \
  87         } while (0)
  88
  89 /*
  90  * returns 0 if test should end.
  91  */
  92 static int test_duration_write(void)
  93 {
  94         return !test_stop;
  95 }
  96
  97 static int test_duration_read(void)
  98 {
  99         return !test_stop;
 100 }
 101
 102 static unsigned long long __thread nr_writes;
 103 static unsigned long long __thread nr_reads;
 104
 105 static unsigned int nr_readers;
 106 static unsigned int nr_writers;
 107
 108 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
 109
 110 void rcu_copy_mutex_lock(void)
 111 {
 112         int ret;
 113         ret = pthread_mutex_lock(&rcu_copy_mutex);
 114         if (ret) {
 115                 perror("Error in pthread mutex lock");
 116                 exit(-1);
 117         }
 118 }
 119
 120 void rcu_copy_mutex_unlock(void)
 121 {
 122         int ret;
 123
 124         ret = pthread_mutex_unlock(&rcu_copy_mutex);
 125         if (ret) {
 126                 perror("Error in pthread mutex unlock");
 127                 exit(-1);
 128         }
 129 }
 130
 131 /*
 132  * malloc/free are reusing memory areas too quickly, which does not let us
 133  * test races appropriately. Use a large circular array for allocations.
 134  * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 135  */
 136 #define ARRAY_SIZE (1048576 * nr_writers)
 137 #define ARRAY_POISON 0xDEADBEEF
 138 static int array_index;
 139 static struct test_array *test_array;
 140
 141 static struct test_array *test_array_alloc(void)
 142 {
 143         struct test_array *ret;
 144         int index;
 145
 146         rcu_copy_mutex_lock();
 147         index = array_index % ARRAY_SIZE;
 148         assert(test_array[index].a == ARRAY_POISON ||
 149                 test_array[index].a == 0);
 150         ret = &test_array[index];
 151         array_index++;
 152         if (array_index == ARRAY_SIZE)
 153                 array_index = 0;
 154         rcu_copy_mutex_unlock();
 155         return ret;
 156 }
 157
 158 static void test_array_free(struct test_array *ptr)
 159 {
 160         if (!ptr)
 161                 return;
 162         rcu_copy_mutex_lock();
 163         ptr->a = ARRAY_POISON;
 164         rcu_copy_mutex_unlock();
 165 }
 166
 167 void *thr_reader(void *_count)
 168 {
 169         unsigned long long *count = _count;
 170         struct test_array *local_ptr;
 171
 172         printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
 173                         "reader", pthread_self(), (unsigned long)gettid());
 174
 175         rcu_register_thread();
 176
 177         while (!test_go)
 178         {
 179         }
 180         smp_mb();
 181
 182         for (;;) {
 183                 rcu_read_lock();
 184                 local_ptr = rcu_dereference(test_rcu_pointer);
 185                 debug_yield_read();
 186                 if (local_ptr)
 187                         assert(local_ptr->a == 8);
 188                 if (unlikely(rduration))
 189                         loop_sleep(rduration);
 190                 rcu_read_unlock();
 191                 nr_reads++;
 192                 if (unlikely(!test_duration_read()))
 193                         break;
 194         }
 195
 196         rcu_unregister_thread();
 197
 198         *count = nr_reads;
 199         printf_verbose("thread_end %s, thread id : %lx, tid %lu\n",
 200                         "reader", pthread_self(), (unsigned long)gettid());
 201         return ((void*)1);
 202
 203 }
 204
 205 void *thr_writer(void *_count)
 206 {
 207         unsigned long long *count = _count;
 208         struct test_array *new, *old;
 209
 210         printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
 211                         "writer", pthread_self(), (unsigned long)gettid());
 212
 213         while (!test_go)
 214         {
 215         }
 216         smp_mb();
 217
 218         for (;;) {
 219                 new = test_array_alloc();
 220                 rcu_copy_mutex_lock();
 221                 old = test_rcu_pointer;
 222                 if (old)
 223                         assert(old->a == 8);
 224                 new->a = 8;
 225                 old = rcu_publish_content(&test_rcu_pointer, new);
 226                 rcu_copy_mutex_unlock();
 227                 /* can be done after unlock */
 228                 if (old)
 229                         old->a = 0;
 230                 test_array_free(old);
 231                 nr_writes++;
 232                 if (unlikely(!test_duration_write()))
 233                         break;
 234                 if (unlikely(wdelay))
 235                         usleep(wdelay);
 236         }
 237
 238         printf_verbose("thread_end %s, thread id : %lx, tid %lu\n",
 239                         "writer", pthread_self(), (unsigned long)gettid());
 240         *count = nr_writes;
 241         return ((void*)2);
 242 }
 243
 244 void show_usage(int argc, char **argv)
 245 {
 246         printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
 247 #ifdef DEBUG_YIELD
 248         printf(" [-r] [-w] (yield reader and/or writer)");
 249 #endif
 250         printf(" [-d delay] (writer period (us))");
 251         printf(" [-c duration] (reader C.S. duration (in loops))");
 252         printf(" [-v] (verbose output)");
 253         printf(" [-a cpu#] [-a cpu#]... (affinity)");
 254         printf("\n");
 255 }
 256
 257 cpu_set_t affinity;
 258
 259 int main(int argc, char **argv)
 260 {
 261         int err;
 262         pthread_t *tid_reader, *tid_writer;
 263         void *tret;
 264         unsigned long long *count_reader, *count_writer;
 265         unsigned long long tot_reads = 0, tot_writes = 0;
 266         int i, a;
 267         int use_affinity = 0;
 268
 269         if (argc < 4) {
 270                 show_usage(argc, argv);
 271                 return -1;
 272         }
 273
 274         err = sscanf(argv[1], "%u", &nr_readers);
 275         if (err != 1) {
 276                 show_usage(argc, argv);
 277                 return -1;
 278         }
 279
 280         err = sscanf(argv[2], "%u", &nr_writers);
 281         if (err != 1) {
 282                 show_usage(argc, argv);
 283                 return -1;
 284         }
 285
 286         err = sscanf(argv[3], "%lu", &duration);
 287         if (err != 1) {
 288                 show_usage(argc, argv);
 289                 return -1;
 290         }
 291
 292         CPU_ZERO(&affinity);
 293
 294         for (i = 4; i < argc; i++) {
 295                 if (argv[i][0] != '-')
 296                         continue;
 297                 switch (argv[i][1]) {
 298 #ifdef DEBUG_YIELD
 299                 case 'r':
 300                         yield_active |= YIELD_READ;
 301                         break;
 302                 case 'w':
 303                         yield_active |= YIELD_WRITE;
 304                         break;
 305 #endif
 306                 case 'a':
 307                         if (argc < i + 2) {
 308                                 show_usage(argc, argv);
 309                                 return -1;
 310                         }
 311                         a = atoi(argv[++i]);
 312                         CPU_SET(a, &affinity);
 313                         use_affinity = 1;
 314                         printf_verbose("Adding CPU %d affinity\n", a);
 315                         break;
 316                 case 'c':
 317                         if (argc < i + 2) {
 318                                 show_usage(argc, argv);
 319                                 return -1;
 320                         }
 321                         rduration = atoi(argv[++i]);
 322                         break;
 323                 case 'd':
 324                         if (argc < i + 2) {
 325                                 show_usage(argc, argv);
 326                                 return -1;
 327                         }
 328                         wdelay = atoi(argv[++i]);
 329                         break;
 330                 case 'v':
 331                         verbose_mode = 1;
 332                         break;
 333                 }
 334         }
 335
 336         printf_verbose("running test for %lu seconds, %u readers, %u writers.\n",
 337                 duration, nr_readers, nr_writers);
 338         printf_verbose("Writer delay : %u us.\n", wdelay);
 339         printf_verbose("Reader duration : %lu loops.\n", rduration);
 340         printf_verbose("thread %-6s, thread id : %lx, tid %lu\n",
 341                         "main", pthread_self(), (unsigned long)gettid());
 342
 343         if (use_affinity
 344             && sched_setaffinity(0, sizeof(affinity), &affinity) < 0) {
 345                 perror("sched_setaffinity");
 346                 exit(-1);
 347         }
 348
 349         test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
 350         tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
 351         tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
 352         count_reader = malloc(sizeof(*count_reader) * nr_readers);
 353         count_writer = malloc(sizeof(*count_writer) * nr_writers);
 354
 355         for (i = 0; i < nr_readers; i++) {
 356                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 357                                      &count_reader[i]);
 358                 if (err != 0)
 359                         exit(1);
 360         }
 361         for (i = 0; i < nr_writers; i++) {
 362                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 363                                      &count_writer[i]);
 364                 if (err != 0)
 365                         exit(1);
 366         }
 367
 368         smp_mb();
 369
 370         test_go = 1;
 371
 372         sleep(duration);
 373
 374         test_stop = 1;
 375
 376         for (i = 0; i < nr_readers; i++) {
 377                 err = pthread_join(tid_reader[i], &tret);
 378                 if (err != 0)
 379                         exit(1);
 380                 tot_reads += count_reader[i];
 381         }
 382         for (i = 0; i < nr_writers; i++) {
 383                 err = pthread_join(tid_writer[i], &tret);
 384                 if (err != 0)
 385                         exit(1);
 386                 tot_writes += count_writer[i];
 387         }
 388
 389         printf_verbose("total number of reads : %llu, writes %llu\n", tot_reads,
 390                tot_writes);
 391         printf("SUMMARY %-15s testdur %4lu nr_readers %3u rdur %6lu "
 392                 "nr_writers %3u "
 393                 "wdelay %4u nr_reads %12llu nr_writes %12llu nr_ops %12llu\n",
 394                 argv[0], duration, nr_readers, rduration,
 395                 nr_writers, wdelay, tot_reads, tot_writes,
 396                 tot_reads + tot_writes);
 397         test_array_free(test_rcu_pointer);
 398         free(test_array);
 399         free(tid_reader);
 400         free(tid_writer);
 401         free(count_reader);
 402         free(count_writer);
 403         return 0;
 404 }