test_rwlock_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 <pthread.h>
  34 #include <arch.h>
  35
  36 /* Make this big enough to include the POWER5+ L3 cacheline size of 256B */
  37 #define CACHE_LINE_SIZE 4096
  38
  39 #if defined(_syscall0)
  40 _syscall0(pid_t, gettid)
  41 #elif defined(__NR_gettid)
  42 static inline pid_t gettid(void)
  43 {
  44         return syscall(__NR_gettid);
  45 }
  46 #else
  47 #warning "use pid as tid"
  48 static inline pid_t gettid(void)
  49 {
  50         return getpid();
  51 }
  52 #endif
  53
  54 #include "urcu.h"
  55
  56 struct test_array {
  57         int a;
  58 };
  59
  60 pthread_rwlock_t lock = PTHREAD_RWLOCK_INITIALIZER;
  61
  62 static struct test_array test_array = { 8 };
  63
  64 #define OUTER_READ_LOOP 200U
  65 #define INNER_READ_LOOP 100000U
  66 #define READ_LOOP ((unsigned long long)OUTER_READ_LOOP * INNER_READ_LOOP)
  67
  68 #define OUTER_WRITE_LOOP 10U
  69 #define INNER_WRITE_LOOP 200U
  70 #define WRITE_LOOP ((unsigned long long)OUTER_WRITE_LOOP * INNER_WRITE_LOOP)
  71
  72 static int num_read;
  73 static int num_write;
  74
  75 #define NR_READ num_read
  76 #define NR_WRITE num_write
  77
  78 static cycles_t __attribute__((aligned(CACHE_LINE_SIZE))) *reader_time;
  79 static cycles_t __attribute__((aligned(CACHE_LINE_SIZE))) *writer_time;
  80
  81 void *thr_reader(void *arg)
  82 {
  83         int i, j;
  84         cycles_t time1, time2;
  85
  86         printf("thread_begin %s, thread id : %lx, tid %lu\n",
  87                         "reader", pthread_self(), (unsigned long)gettid());
  88         sleep(2);
  89
  90         time1 = get_cycles();
  91         for (i = 0; i < OUTER_READ_LOOP; i++) {
  92                 for (j = 0; j < INNER_READ_LOOP; j++) {
  93                         pthread_rwlock_rdlock(&lock);
  94                         assert(test_array.a == 8);
  95                         pthread_rwlock_unlock(&lock);
  96                 }
  97         }
  98         time2 = get_cycles();
  99
 100         reader_time[(unsigned long)arg] = time2 - time1;
 101
 102         sleep(2);
 103         printf("thread_end %s, thread id : %lx, tid %lu\n",
 104                         "reader", pthread_self(), (unsigned long)gettid());
 105         return ((void*)1);
 106
 107 }
 108
 109 void *thr_writer(void *arg)
 110 {
 111         int i, j;
 112         cycles_t time1, time2;
 113
 114         printf("thread_begin %s, thread id : %lx, tid %lu\n",
 115                         "writer", pthread_self(), (unsigned long)gettid());
 116         sleep(2);
 117
 118         for (i = 0; i < OUTER_WRITE_LOOP; i++) {
 119                 for (j = 0; j < INNER_WRITE_LOOP; j++) {
 120                         time1 = get_cycles();
 121                         pthread_rwlock_wrlock(&lock);
 122                         test_array.a = 8;
 123                         pthread_rwlock_unlock(&lock);
 124                         time2 = get_cycles();
 125                         writer_time[(unsigned long)arg] += time2 - time1;
 126                         usleep(1);
 127                 }
 128         }
 129
 130         printf("thread_end %s, thread id : %lx, tid %lu\n",
 131                         "writer", pthread_self(), (unsigned long)gettid());
 132         return ((void*)2);
 133 }
 134
 135 int main(int argc, char **argv)
 136 {
 137         int err;
 138         pthread_t *tid_reader, *tid_writer;
 139         void *tret;
 140         int i;
 141         cycles_t tot_rtime = 0;
 142         cycles_t tot_wtime = 0;
 143
 144         if (argc < 2) {
 145                 printf("Usage : %s nr_readers nr_writers\n", argv[0]);
 146                 exit(-1);
 147         }
 148         num_read = atoi(argv[1]);
 149         num_write = atoi(argv[2]);
 150
 151         reader_time = malloc(sizeof(*reader_time) * num_read);
 152         writer_time = malloc(sizeof(*writer_time) * num_write);
 153         tid_reader = malloc(sizeof(*tid_reader) * num_read);
 154         tid_writer = malloc(sizeof(*tid_writer) * num_write);
 155
 156         printf("thread %-6s, thread id : %lx, tid %lu\n",
 157                         "main", pthread_self(), (unsigned long)gettid());
 158
 159         for (i = 0; i < NR_READ; i++) {
 160                 err = pthread_create(&tid_reader[i], NULL, thr_reader,
 161                                      (void *)(long)i);
 162                 if (err != 0)
 163                         exit(1);
 164         }
 165         for (i = 0; i < NR_WRITE; i++) {
 166                 err = pthread_create(&tid_writer[i], NULL, thr_writer,
 167                                      (void *)(long)i);
 168                 if (err != 0)
 169                         exit(1);
 170         }
 171
 172         sleep(10);
 173
 174         for (i = 0; i < NR_READ; i++) {
 175                 err = pthread_join(tid_reader[i], &tret);
 176                 if (err != 0)
 177                         exit(1);
 178                 tot_rtime += reader_time[i];
 179         }
 180         for (i = 0; i < NR_WRITE; i++) {
 181                 err = pthread_join(tid_writer[i], &tret);
 182                 if (err != 0)
 183                         exit(1);
 184                 tot_wtime += writer_time[i];
 185         }
 186         printf("Time per read : %g cycles\n",
 187                (double)tot_rtime / ((double)NR_READ * (double)READ_LOOP));
 188         printf("Time per write : %g cycles\n",
 189                (double)tot_wtime / ((double)NR_WRITE * (double)WRITE_LOOP));
 190
 191         free(reader_time);
 192         free(writer_time);
 193         free(tid_reader);
 194         free(tid_writer);
 195
 196         return 0;
 197 }