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