tests/test_urcu_timing.c

   1 /*
   2  * test_urcu.c
   3  *
   4  * Userspace RCU library - test program
   5  *
   6  * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   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 <errno.h>
  33 #include <urcu/arch.h>
  34
  35 #ifdef __linux__
  36 #include <syscall.h>
  37 #endif
  38
  39 #if defined(_syscall0)
  40 _syscall0(pid_t, gettid)
  41 #elif defined(__NR_gettid)
  42 static inline pid_t gettid(void)
  43 {
  44         return syscall(__NR_gettid);
  45 }
  46 #else
  47 #warning "use pid as tid"
  48 static inline pid_t gettid(void)
  49 {
  50         return getpid();
  51 }
  52 #endif
  53
  54 #define _LGPL_SOURCE
  55 #include <urcu.h>
  56
  57 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  58
  59 void rcu_copy_mutex_lock(void)
  60 {
  61         int ret;
  62         ret = pthread_mutex_lock(&rcu_copy_mutex);
  63         if (ret) {
  64                 perror("Error in pthread mutex lock");
  65                 exit(-1);
  66         }
  67 }
  68
  69 void rcu_copy_mutex_unlock(void)
  70 {
  71         int ret;
  72
  73         ret = pthread_mutex_unlock(&rcu_copy_mutex);
  74         if (ret) {
  75                 perror("Error in pthread mutex unlock");
  76                 exit(-1);
  77         }
  78 }
  79
  80 struct test_array {
  81         int a;
  82 };
  83
  84 static struct test_array *test_rcu_pointer;
  85
  86 #define OUTER_READ_LOOP 2000U
  87 #define INNER_READ_LOOP 100000U
  88 #define READ_LOOP ((unsigned long long)OUTER_READ_LOOP * INNER_READ_LOOP)
  89
  90 #define OUTER_WRITE_LOOP 10U
  91 #define INNER_WRITE_LOOP 200U
  92 #define WRITE_LOOP ((unsigned long long)OUTER_WRITE_LOOP * INNER_WRITE_LOOP)
  93
  94 static int num_read;
  95 static int num_write;
  96
  97 #define NR_READ num_read
  98 #define NR_WRITE num_write
  99
 100 static cycles_t __attribute__((aligned(CAA_CACHE_LINE_SIZE))) *reader_time;
 101 static cycles_t __attribute__((aligned(CAA_CACHE_LINE_SIZE))) *writer_time;
 102
 103 void *thr_reader(void *arg)
 104 {
 105         int i, j;
 106         struct test_array *local_ptr;
 107         cycles_t time1, time2;
 108
 109         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 110                         "reader", (unsigned long) pthread_self(),
 111                         (unsigned long) gettid());
 112         sleep(2);
 113
 114         rcu_register_thread();
 115
 116         time1 = caa_get_cycles();
 117         for (i = 0; i < OUTER_READ_LOOP; i++) {
 118                 for (j = 0; j < INNER_READ_LOOP; j++) {
 119                         rcu_read_lock();
 120                         local_ptr = rcu_dereference(test_rcu_pointer);
 121                         if (local_ptr) {
 122                                 assert(local_ptr->a == 8);
 123                         }
 124                         rcu_read_unlock();
 125                 }
 126         }
 127         time2 = caa_get_cycles();
 128
 129         rcu_unregister_thread();
 130
 131         reader_time[(unsigned long)arg] = time2 - time1;
 132
 133         sleep(2);
 134         printf("thread_end %s, thread id : %lx, tid %lu\n",
 135                         "reader", (unsigned long) pthread_self(),
 136                         (unsigned long) gettid());
 137         return ((void*)1);
 138
 139 }
 140
 141 void *thr_writer(void *arg)
 142 {
 143         int i, j;
 144         struct test_array *new, *old;
 145         cycles_t time1, time2;
 146
 147         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 148                         "writer", (unsigned long) pthread_self(),
 149                         (unsigned long) gettid());
 150         sleep(2);
 151
 152         for (i = 0; i < OUTER_WRITE_LOOP; i++) {
 153                 for (j = 0; j < INNER_WRITE_LOOP; j++) {
 154                         time1 = caa_get_cycles();
 155                         new = malloc(sizeof(struct test_array));
 156                         rcu_copy_mutex_lock();
 157                         old = test_rcu_pointer;
 158                         if (old) {
 159                                 assert(old->a == 8);
 160                         }
 161                         new->a = 8;
 162                         old = rcu_xchg_pointer(&test_rcu_pointer, new);
 163                         rcu_copy_mutex_unlock();
 164                         synchronize_rcu();
 165                         /* can be done after unlock */
 166                         if (old) {
 167                                 old->a = 0;
 168                         }
 169                         free(old);
 170                         time2 = caa_get_cycles();
 171                         writer_time[(unsigned long)arg] += time2 - time1;
 172                         usleep(1);
 173                 }
 174         }
 175
 176         printf("thread_end %s, thread id : %lx, tid %lu\n",
 177                         "writer", (unsigned long) pthread_self(),
 178                         (unsigned long) gettid());
 179         return ((void*)2);
 180 }
 181
 182 int main(int argc, char **argv)
 183 {
 184         int err;
 185         pthread_t *tid_reader, *tid_writer;
 186         void *tret;
 187         int i;
 188         cycles_t tot_rtime = 0;
 189         cycles_t tot_wtime = 0;
 190
 191         if (argc < 2) {
 192                 printf("Usage : %s nr_readers nr_writers\n", argv[0]);
 193                 exit(-1);
 194         }
 195         num_read = atoi(argv[1]);
 196         num_write = atoi(argv[2]);
 197
 198         reader_time = malloc(sizeof(*reader_time) * num_read);
 199         writer_time = malloc(sizeof(*writer_time) * num_write);
 200         tid_reader = malloc(sizeof(*tid_reader) * num_read);
 201         tid_writer = malloc(sizeof(*tid_writer) * num_write);
 202
 203         printf("thread %-6s, thread id : %lx, tid %lu\n",
 204                         "main", (unsigned long) pthread_self(),
 205                         (unsigned long) gettid());
 206
 207         for (i = 0; i < NR_READ; i++) {
 208                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 209                                      (void *)(long)i);
 210                 if (err != 0)
 211                         exit(1);
 212         }
 213         for (i = 0; i < NR_WRITE; i++) {
 214                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 215                                      (void *)(long)i);
 216                 if (err != 0)
 217                         exit(1);
 218         }
 219
 220         sleep(10);
 221
 222         for (i = 0; i < NR_READ; i++) {
 223                 err = pthread_join(tid_reader[i], &tret);
 224                 if (err != 0)
 225                         exit(1);
 226                 tot_rtime += reader_time[i];
 227         }
 228         for (i = 0; i < NR_WRITE; i++) {
 229                 err = pthread_join(tid_writer[i], &tret);
 230                 if (err != 0)
 231                         exit(1);
 232                 tot_wtime += writer_time[i];
 233         }
 234         free(test_rcu_pointer);
 235         printf("Time per read : %g cycles\n",
 236                (double)tot_rtime / ((double)NR_READ * (double)READ_LOOP));
 237         printf("Time per write : %g cycles\n",
 238                (double)tot_wtime / ((double)NR_WRITE * (double)WRITE_LOOP));
 239
 240         free(reader_time);
 241         free(writer_time);
 242         free(tid_reader);
 243         free(tid_writer);
 244
 245         return 0;
 246 }