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", pthread_self(), (unsigned long)gettid());
 111         sleep(2);
 112
 113         rcu_register_thread();
 114
 115         time1 = caa_get_cycles();
 116         for (i = 0; i < OUTER_READ_LOOP; i++) {
 117                 for (j = 0; j < INNER_READ_LOOP; j++) {
 118                         rcu_read_lock();
 119                         local_ptr = rcu_dereference(test_rcu_pointer);
 120                         if (local_ptr) {
 121                                 assert(local_ptr->a == 8);
 122                         }
 123                         rcu_read_unlock();
 124                 }
 125         }
 126         time2 = caa_get_cycles();
 127
 128         rcu_unregister_thread();
 129
 130         reader_time[(unsigned long)arg] = time2 - time1;
 131
 132         sleep(2);
 133         printf("thread_end %s, thread id : %lx, tid %lu\n",
 134                         "reader", pthread_self(), (unsigned long)gettid());
 135         return ((void*)1);
 136
 137 }
 138
 139 void *thr_writer(void *arg)
 140 {
 141         int i, j;
 142         struct test_array *new, *old;
 143         cycles_t time1, time2;
 144
 145         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 146                         "writer", pthread_self(), (unsigned long)gettid());
 147         sleep(2);
 148
 149         for (i = 0; i < OUTER_WRITE_LOOP; i++) {
 150                 for (j = 0; j < INNER_WRITE_LOOP; j++) {
 151                         time1 = caa_get_cycles();
 152                         new = malloc(sizeof(struct test_array));
 153                         rcu_copy_mutex_lock();
 154                         old = test_rcu_pointer;
 155                         if (old) {
 156                                 assert(old->a == 8);
 157                         }
 158                         new->a = 8;
 159                         old = rcu_xchg_pointer(&test_rcu_pointer, new);
 160                         rcu_copy_mutex_unlock();
 161                         synchronize_rcu();
 162                         /* can be done after unlock */
 163                         if (old) {
 164                                 old->a = 0;
 165                         }
 166                         free(old);
 167                         time2 = caa_get_cycles();
 168                         writer_time[(unsigned long)arg] += time2 - time1;
 169                         usleep(1);
 170                 }
 171         }
 172
 173         printf("thread_end %s, thread id : %lx, tid %lu\n",
 174                         "writer", pthread_self(), (unsigned long)gettid());
 175         return ((void*)2);
 176 }
 177
 178 int main(int argc, char **argv)
 179 {
 180         int err;
 181         pthread_t *tid_reader, *tid_writer;
 182         void *tret;
 183         int i;
 184         cycles_t tot_rtime = 0;
 185         cycles_t tot_wtime = 0;
 186
 187         if (argc < 2) {
 188                 printf("Usage : %s nr_readers nr_writers\n", argv[0]);
 189                 exit(-1);
 190         }
 191         num_read = atoi(argv[1]);
 192         num_write = atoi(argv[2]);
 193
 194         reader_time = malloc(sizeof(*reader_time) * num_read);
 195         writer_time = malloc(sizeof(*writer_time) * num_write);
 196         tid_reader = malloc(sizeof(*tid_reader) * num_read);
 197         tid_writer = malloc(sizeof(*tid_writer) * num_write);
 198
 199         printf("thread %-6s, thread id : %lx, tid %lu\n",
 200                         "main", pthread_self(), (unsigned long)gettid());
 201
 202         for (i = 0; i < NR_READ; i++) {
 203                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 204                                      (void *)(long)i);
 205                 if (err != 0)
 206                         exit(1);
 207         }
 208         for (i = 0; i < NR_WRITE; i++) {
 209                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 210                                      (void *)(long)i);
 211                 if (err != 0)
 212                         exit(1);
 213         }
 214
 215         sleep(10);
 216
 217         for (i = 0; i < NR_READ; i++) {
 218                 err = pthread_join(tid_reader[i], &tret);
 219                 if (err != 0)
 220                         exit(1);
 221                 tot_rtime += reader_time[i];
 222         }
 223         for (i = 0; i < NR_WRITE; i++) {
 224                 err = pthread_join(tid_writer[i], &tret);
 225                 if (err != 0)
 226                         exit(1);
 227                 tot_wtime += writer_time[i];
 228         }
 229         free(test_rcu_pointer);
 230         printf("Time per read : %g cycles\n",
 231                (double)tot_rtime / ((double)NR_READ * (double)READ_LOOP));
 232         printf("Time per write : %g cycles\n",
 233                (double)tot_wtime / ((double)NR_WRITE * (double)WRITE_LOOP));
 234
 235         free(reader_time);
 236         free(writer_time);
 237         free(tid_reader);
 238         free(tid_writer);
 239
 240         return 0;
 241 }