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