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@polymtl.ca>
   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 "../arch.h"
  34
  35 /* Make this big enough to include the POWER5+ L3 cacheline size of 256B */
  36 #define CACHE_LINE_SIZE 4096
  37
  38 #if defined(_syscall0)
  39 _syscall0(pid_t, gettid)
  40 #elif defined(__NR_gettid)
  41 static inline pid_t gettid(void)
  42 {
  43         return syscall(__NR_gettid);
  44 }
  45 #else
  46 #warning "use pid as tid"
  47 static inline pid_t gettid(void)
  48 {
  49         return getpid();
  50 }
  51 #endif
  52
  53 #define _LGPL_SOURCE
  54 #include "../urcu.h"
  55
  56 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  57
  58 void rcu_copy_mutex_lock(void)
  59 {
  60         int ret;
  61         ret = pthread_mutex_lock(&rcu_copy_mutex);
  62         if (ret) {
  63                 perror("Error in pthread mutex lock");
  64                 exit(-1);
  65         }
  66 }
  67
  68 void rcu_copy_mutex_unlock(void)
  69 {
  70         int ret;
  71
  72         ret = pthread_mutex_unlock(&rcu_copy_mutex);
  73         if (ret) {
  74                 perror("Error in pthread mutex unlock");
  75                 exit(-1);
  76         }
  77 }
  78
  79 struct test_array {
  80         int a;
  81 };
  82
  83 static struct test_array *test_rcu_pointer;
  84
  85 #define OUTER_READ_LOOP 2000U
  86 #define INNER_READ_LOOP 100000U
  87 #define READ_LOOP ((unsigned long long)OUTER_READ_LOOP * INNER_READ_LOOP)
  88
  89 #define OUTER_WRITE_LOOP 10U
  90 #define INNER_WRITE_LOOP 200U
  91 #define WRITE_LOOP ((unsigned long long)OUTER_WRITE_LOOP * INNER_WRITE_LOOP)
  92
  93 static int num_read;
  94 static int num_write;
  95
  96 #define NR_READ num_read
  97 #define NR_WRITE num_write
  98
  99 static cycles_t __attribute__((aligned(CACHE_LINE_SIZE))) *reader_time;
 100 static cycles_t __attribute__((aligned(CACHE_LINE_SIZE))) *writer_time;
 101
 102 void *thr_reader(void *arg)
 103 {
 104         int i, j;
 105         struct test_array *local_ptr;
 106         cycles_t time1, time2;
 107
 108         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 109                         "reader", pthread_self(), (unsigned long)gettid());
 110         sleep(2);
 111
 112         rcu_register_thread();
 113
 114         time1 = get_cycles();
 115         for (i = 0; i < OUTER_READ_LOOP; i++) {
 116                 for (j = 0; j < INNER_READ_LOOP; j++) {
 117                         rcu_read_lock();
 118                         local_ptr = rcu_dereference(test_rcu_pointer);
 119                         if (local_ptr) {
 120                                 assert(local_ptr->a == 8);
 121                         }
 122                         rcu_read_unlock();
 123                 }
 124         }
 125         time2 = 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 = 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_publish_content(&test_rcu_pointer, new);
 159                         rcu_copy_mutex_unlock();
 160                         /* can be done after unlock */
 161                         if (old) {
 162                                 old->a = 0;
 163                         }
 164                         free(old);
 165                         time2 = get_cycles();
 166                         writer_time[(unsigned long)arg] += time2 - time1;
 167                         usleep(1);
 168                 }
 169         }
 170
 171         printf("thread_end %s, thread id : %lx, tid %lu\n",
 172                         "writer", pthread_self(), (unsigned long)gettid());
 173         return ((void*)2);
 174 }
 175
 176 int main(int argc, char **argv)
 177 {
 178         int err;
 179         pthread_t *tid_reader, *tid_writer;
 180         void *tret;
 181         int i;
 182         cycles_t tot_rtime = 0;
 183         cycles_t tot_wtime = 0;
 184
 185         if (argc < 2) {
 186                 printf("Usage : %s nr_readers nr_writers\n", argv[0]);
 187                 exit(-1);
 188         }
 189         num_read = atoi(argv[1]);
 190         num_write = atoi(argv[2]);
 191
 192         reader_time = malloc(sizeof(*reader_time) * num_read);
 193         writer_time = malloc(sizeof(*writer_time) * num_write);
 194         tid_reader = malloc(sizeof(*tid_reader) * num_read);
 195         tid_writer = malloc(sizeof(*tid_writer) * num_write);
 196
 197         printf("thread %-6s, thread id : %lx, tid %lu\n",
 198                         "main", pthread_self(), (unsigned long)gettid());
 199
 200         for (i = 0; i < NR_READ; i++) {
 201                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 202                                      (void *)(long)i);
 203                 if (err != 0)
 204                         exit(1);
 205         }
 206         for (i = 0; i < NR_WRITE; i++) {
 207                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 208                                      (void *)(long)i);
 209                 if (err != 0)
 210                         exit(1);
 211         }
 212
 213         sleep(10);
 214
 215         for (i = 0; i < NR_READ; i++) {
 216                 err = pthread_join(tid_reader[i], &tret);
 217                 if (err != 0)
 218                         exit(1);
 219                 tot_rtime += reader_time[i];
 220         }
 221         for (i = 0; i < NR_WRITE; i++) {
 222                 err = pthread_join(tid_writer[i], &tret);
 223                 if (err != 0)
 224                         exit(1);
 225                 tot_wtime += writer_time[i];
 226         }
 227         free(test_rcu_pointer);
 228         printf("Time per read : %g cycles\n",
 229                (double)tot_rtime / ((double)NR_READ * (double)READ_LOOP));
 230         printf("Time per write : %g cycles\n",
 231                (double)tot_wtime / ((double)NR_WRITE * (double)WRITE_LOOP));
 232
 233         free(reader_time);
 234         free(writer_time);
 235         free(tid_reader);
 236         free(tid_writer);
 237
 238         return 0;
 239 }