1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/*
* rwlock8.c
*
* Hammer on a bunch of rwlocks to test robustness and fairness.
* Printed stats should be roughly even for each thread.
*
* Yield during each access to exercise lock contention code paths
* more than rwlock7.c does (particularly on uni-processor systems).
*/
#include "test.h"
#include <sys/timeb.h>
#ifdef __GNUC__
#include <stdlib.h>
#endif
#define THREADS 5
#define DATASIZE 7
#define ITERATIONS 100000
/*
* Keep statistics for each thread.
*/
typedef struct thread_tag {
int thread_num;
pthread_t thread_id;
int updates;
int reads;
int changed;
int seed;
} thread_t;
/*
* Read-write lock and shared data
*/
typedef struct data_tag {
pthread_rwlock_t lock;
int data;
int updates;
} data_t;
static thread_t threads[THREADS];
static data_t data[DATASIZE];
/*
* Thread start routine that uses read-write locks
*/
void *thread_routine (void *arg)
{
thread_t *self = (thread_t*)arg;
int iteration;
int element = 0;
int seed = self->seed;
int interval = 1 + rand_r (&seed) % 71;
self->changed = 0;
for (iteration = 0; iteration < ITERATIONS; iteration++)
{
if (iteration % (ITERATIONS / 10) == 0)
{
putchar('.');
fflush(stdout);
}
/*
* Each "self->interval" iterations, perform an
* update operation (write lock instead of read
* lock).
*/
if ((iteration % interval) == 0)
{
assert(pthread_rwlock_wrlock (&data[element].lock) == 0);
data[element].data = self->thread_num;
data[element].updates++;
self->updates++;
interval = 1 + rand_r (&seed) % 71;
sched_yield();
assert(pthread_rwlock_unlock (&data[element].lock) == 0);
} else {
/*
* Look at the current data element to see whether
* the current thread last updated it. Count the
* times, to report later.
*/
assert(pthread_rwlock_rdlock (&data[element].lock) == 0);
self->reads++;
if (data[element].data != self->thread_num)
{
self->changed++;
interval = 1 + self->changed % 71;
}
sched_yield();
assert(pthread_rwlock_unlock (&data[element].lock) == 0);
}
element = (element + 1) % DATASIZE;
}
return NULL;
}
int
main (int argc, char *argv[])
{
int count;
int data_count;
int thread_updates = 0;
int data_updates = 0;
int seed = 1;
struct _timeb currSysTime1;
struct _timeb currSysTime2;
/*
* Initialize the shared data.
*/
for (data_count = 0; data_count < DATASIZE; data_count++)
{
data[data_count].data = 0;
data[data_count].updates = 0;
assert(pthread_rwlock_init (&data[data_count].lock, NULL) == 0);
}
PTW32_FTIME(&currSysTime1);
/*
* Create THREADS threads to access shared data.
*/
for (count = 0; count < THREADS; count++)
{
threads[count].thread_num = count;
threads[count].updates = 0;
threads[count].reads = 0;
threads[count].seed = 1 + rand_r (&seed) % 71;
assert(pthread_create (&threads[count].thread_id,
NULL, thread_routine, (void*)&threads[count]) == 0);
}
/*
* Wait for all threads to complete, and collect
* statistics.
*/
for (count = 0; count < THREADS; count++)
{
assert(pthread_join (threads[count].thread_id, NULL) == 0);
}
putchar('\n');
fflush(stdout);
for (count = 0; count < THREADS; count++)
{
if (threads[count].changed > 0)
{
printf ("Thread %d found changed elements %d times\n",
count, threads[count].changed);
}
}
putchar('\n');
fflush(stdout);
for (count = 0; count < THREADS; count++)
{
thread_updates += threads[count].updates;
printf ("%02d: seed %d, updates %d, reads %d\n",
count, threads[count].seed,
threads[count].updates, threads[count].reads);
}
putchar('\n');
fflush(stdout);
/*
* Collect statistics for the data.
*/
for (data_count = 0; data_count < DATASIZE; data_count++)
{
data_updates += data[data_count].updates;
printf ("data %02d: value %d, %d updates\n",
data_count, data[data_count].data, data[data_count].updates);
assert(pthread_rwlock_destroy (&data[data_count].lock) == 0);
}
printf ("%d thread updates, %d data updates\n",
thread_updates, data_updates);
PTW32_FTIME(&currSysTime2);
printf( "\nstart: %ld/%d, stop: %ld/%d, duration:%ld\n",
currSysTime1.time,currSysTime1.millitm,
currSysTime2.time,currSysTime2.millitm,
((long)((currSysTime2.time*1000+currSysTime2.millitm) -
(currSysTime1.time*1000+currSysTime1.millitm))));
return 0;
}
|
