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