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