tests/benchmark/test_urcu_timing.c

   1 // SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   2 //
   3 // SPDX-License-Identifier: GPL-2.0-or-later
   4
   5 /*
   6  * Userspace RCU library - test program
   7  */
   8
   9 #include <stdio.h>
  10 #include <pthread.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/types.h>
  14 #include <sys/wait.h>
  15 #include <unistd.h>
  16 #include <stdio.h>
  17 #include <errno.h>
  18
  19 #include <urcu/arch.h>
  20 #include <urcu/assert.h>
  21
  22 #include "thread-id.h"
  23
  24 #define _LGPL_SOURCE
  25 #include <urcu.h>
  26
  27 pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
  28
  29 static
  30 void rcu_copy_mutex_lock(void)
  31 {
  32         int ret;
  33         ret = pthread_mutex_lock(&rcu_copy_mutex);
  34         if (ret) {
  35                 perror("Error in pthread mutex lock");
  36                 exit(-1);
  37         }
  38 }
  39
  40 static
  41 void rcu_copy_mutex_unlock(void)
  42 {
  43         int ret;
  44
  45         ret = pthread_mutex_unlock(&rcu_copy_mutex);
  46         if (ret) {
  47                 perror("Error in pthread mutex unlock");
  48                 exit(-1);
  49         }
  50 }
  51
  52 struct test_array {
  53         int a;
  54 };
  55
  56 static struct test_array *test_rcu_pointer;
  57
  58 #define OUTER_READ_LOOP 2000U
  59 #define INNER_READ_LOOP 100000U
  60 #define READ_LOOP ((unsigned long long)OUTER_READ_LOOP * INNER_READ_LOOP)
  61
  62 #define OUTER_WRITE_LOOP 10U
  63 #define INNER_WRITE_LOOP 200U
  64 #define WRITE_LOOP ((unsigned long long)OUTER_WRITE_LOOP * INNER_WRITE_LOOP)
  65
  66 static int num_read;
  67 static int num_write;
  68
  69 #define NR_READ num_read
  70 #define NR_WRITE num_write
  71
  72 static caa_cycles_t __attribute__((aligned(CAA_CACHE_LINE_SIZE))) *reader_time;
  73 static caa_cycles_t __attribute__((aligned(CAA_CACHE_LINE_SIZE))) *writer_time;
  74
  75 static
  76 void *thr_reader(void *arg)
  77 {
  78         unsigned int i, j;
  79         struct test_array *local_ptr;
  80         caa_cycles_t time1, time2;
  81
  82         printf("thread_begin %s, tid %lu\n",
  83                 "reader", urcu_get_thread_id());
  84         sleep(2);
  85
  86         rcu_register_thread();
  87
  88         time1 = caa_get_cycles();
  89         for (i = 0; i < OUTER_READ_LOOP; i++) {
  90                 for (j = 0; j < INNER_READ_LOOP; j++) {
  91                         rcu_read_lock();
  92                         local_ptr = rcu_dereference(test_rcu_pointer);
  93                         if (local_ptr) {
  94                                 urcu_posix_assert(local_ptr->a == 8);
  95                         }
  96                         rcu_read_unlock();
  97                 }
  98         }
  99         time2 = caa_get_cycles();
 100
 101         rcu_unregister_thread();
 102
 103         reader_time[(unsigned long)arg] = time2 - time1;
 104
 105         sleep(2);
 106         printf("thread_end %s, tid %lu\n",
 107                 "reader", urcu_get_thread_id());
 108         return ((void*)1);
 109
 110 }
 111
 112 static
 113 void *thr_writer(void *arg)
 114 {
 115         unsigned int i, j;
 116         struct test_array *new, *old;
 117         caa_cycles_t time1, time2;
 118
 119         printf("thread_begin %s, tid %lu\n",
 120                 "writer", urcu_get_thread_id());
 121         sleep(2);
 122
 123         for (i = 0; i < OUTER_WRITE_LOOP; i++) {
 124                 for (j = 0; j < INNER_WRITE_LOOP; j++) {
 125                         time1 = caa_get_cycles();
 126                         new = malloc(sizeof(struct test_array));
 127                         rcu_copy_mutex_lock();
 128                         old = test_rcu_pointer;
 129                         if (old) {
 130                                 urcu_posix_assert(old->a == 8);
 131                         }
 132                         new->a = 8;
 133                         old = rcu_xchg_pointer(&test_rcu_pointer, new);
 134                         rcu_copy_mutex_unlock();
 135                         synchronize_rcu();
 136                         /* can be done after unlock */
 137                         if (old) {
 138                                 old->a = 0;
 139                         }
 140                         free(old);
 141                         time2 = caa_get_cycles();
 142                         writer_time[(unsigned long)arg] += time2 - time1;
 143                         usleep(1);
 144                 }
 145         }
 146
 147         printf("thread_end %s, tid %lu\n",
 148                 "writer", urcu_get_thread_id());
 149         return ((void*)2);
 150 }
 151
 152 int main(int argc, char **argv)
 153 {
 154         int err;
 155         pthread_t *tid_reader, *tid_writer;
 156         void *tret;
 157         int i;
 158         caa_cycles_t tot_rtime = 0;
 159         caa_cycles_t tot_wtime = 0;
 160
 161         if (argc < 2) {
 162                 printf("Usage : %s nr_readers nr_writers\n", argv[0]);
 163                 exit(-1);
 164         }
 165         num_read = atoi(argv[1]);
 166         num_write = atoi(argv[2]);
 167
 168         reader_time = calloc(num_read, sizeof(*reader_time));
 169         writer_time = calloc(num_write, sizeof(*writer_time));
 170         tid_reader = calloc(num_read, sizeof(*tid_reader));
 171         tid_writer = calloc(num_write, sizeof(*tid_writer));
 172
 173         printf("thread %-6s, tid %lu\n",
 174                 "main", urcu_get_thread_id());
 175
 176         for (i = 0; i < NR_READ; i++) {
 177                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 178                                      (void *)(long)i);
 179                 if (err != 0)
 180                         exit(1);
 181         }
 182         for (i = 0; i < NR_WRITE; i++) {
 183                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 184                                      (void *)(long)i);
 185                 if (err != 0)
 186                         exit(1);
 187         }
 188
 189         sleep(10);
 190
 191         for (i = 0; i < NR_READ; i++) {
 192                 err = pthread_join(tid_reader[i], &tret);
 193                 if (err != 0)
 194                         exit(1);
 195                 tot_rtime += reader_time[i];
 196         }
 197         for (i = 0; i < NR_WRITE; i++) {
 198                 err = pthread_join(tid_writer[i], &tret);
 199                 if (err != 0)
 200                         exit(1);
 201                 tot_wtime += writer_time[i];
 202         }
 203         free(test_rcu_pointer);
 204         printf("Time per read : %g cycles\n",
 205                (double)tot_rtime / ((double)NR_READ * (double)READ_LOOP));
 206         printf("Time per write : %g cycles\n",
 207                (double)tot_wtime / ((double)NR_WRITE * (double)WRITE_LOOP));
 208
 209         free(reader_time);
 210         free(writer_time);
 211         free(tid_reader);
 212         free(tid_writer);
 213
 214         return 0;
 215 }