tests/test_qsbr_timing.c

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