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
|
This patch fixes performance problems on multi-core machines
as reported at <https://bugs.gnu.org/26441>.
See commit 480d374e596a0ee3fed168ab42cd84c313ad3c89 in Gnulib
by Bruno Haible <bruno@clisp.org>.
diff --git a/gettext-tools/gnulib-tests/test-lock.c b/gettext-tools/gnulib-tests/test-lock.c
index cb734b4e6..aa6de2739 100644
--- a/gettext-tools/gnulib-tests/test-lock.c
+++ b/gettext-tools/gnulib-tests/test-lock.c
@@ -50,6 +50,13 @@
Uncomment this to see if the operating system has a fair scheduler. */
#define EXPLICIT_YIELD 1
+/* Whether to use 'volatile' on some variables that communicate information
+ between threads. If set to 0, a lock is used to protect these variables.
+ If set to 1, 'volatile' is used; this is theoretically equivalent but can
+ lead to much slower execution (e.g. 30x slower total run time on a 40-core
+ machine. */
+#define USE_VOLATILE 0
+
/* Whether to print debugging messages. */
#define ENABLE_DEBUGGING 0
@@ -103,6 +110,51 @@
# define yield()
#endif
+#if USE_VOLATILE
+struct atomic_int {
+ volatile int value;
+};
+static void
+init_atomic_int (struct atomic_int *ai)
+{
+}
+static int
+get_atomic_int_value (struct atomic_int *ai)
+{
+ return ai->value;
+}
+static void
+set_atomic_int_value (struct atomic_int *ai, int new_value)
+{
+ ai->value = new_value;
+}
+#else
+struct atomic_int {
+ gl_lock_define (, lock)
+ int value;
+};
+static void
+init_atomic_int (struct atomic_int *ai)
+{
+ gl_lock_init (ai->lock);
+}
+static int
+get_atomic_int_value (struct atomic_int *ai)
+{
+ gl_lock_lock (ai->lock);
+ int ret = ai->value;
+ gl_lock_unlock (ai->lock);
+ return ret;
+}
+static void
+set_atomic_int_value (struct atomic_int *ai, int new_value)
+{
+ gl_lock_lock (ai->lock);
+ ai->value = new_value;
+ gl_lock_unlock (ai->lock);
+}
+#endif
+
#define ACCOUNT_COUNT 4
static int account[ACCOUNT_COUNT];
@@ -170,12 +222,12 @@ lock_mutator_thread (void *arg)
return NULL;
}
-static volatile int lock_checker_done;
+static struct atomic_int lock_checker_done;
static void *
lock_checker_thread (void *arg)
{
- while (!lock_checker_done)
+ while (get_atomic_int_value (&lock_checker_done) == 0)
{
dbgprintf ("Checker %p before check lock\n", gl_thread_self_pointer ());
gl_lock_lock (my_lock);
@@ -200,7 +252,8 @@ test_lock (void)
/* Initialization. */
for (i = 0; i < ACCOUNT_COUNT; i++)
account[i] = 1000;
- lock_checker_done = 0;
+ init_atomic_int (&lock_checker_done);
+ set_atomic_int_value (&lock_checker_done, 0);
/* Spawn the threads. */
checkerthread = gl_thread_create (lock_checker_thread, NULL);
@@ -210,7 +263,7 @@ test_lock (void)
/* Wait for the threads to terminate. */
for (i = 0; i < THREAD_COUNT; i++)
gl_thread_join (threads[i], NULL);
- lock_checker_done = 1;
+ set_atomic_int_value (&lock_checker_done, 1);
gl_thread_join (checkerthread, NULL);
check_accounts ();
}
@@ -254,12 +307,12 @@ rwlock_mutator_thread (void *arg)
return NULL;
}
-static volatile int rwlock_checker_done;
+static struct atomic_int rwlock_checker_done;
static void *
rwlock_checker_thread (void *arg)
{
- while (!rwlock_checker_done)
+ while (get_atomic_int_value (&rwlock_checker_done) == 0)
{
dbgprintf ("Checker %p before check rdlock\n", gl_thread_self_pointer ());
gl_rwlock_rdlock (my_rwlock);
@@ -284,7 +337,8 @@ test_rwlock (void)
/* Initialization. */
for (i = 0; i < ACCOUNT_COUNT; i++)
account[i] = 1000;
- rwlock_checker_done = 0;
+ init_atomic_int (&rwlock_checker_done);
+ set_atomic_int_value (&rwlock_checker_done, 0);
/* Spawn the threads. */
for (i = 0; i < THREAD_COUNT; i++)
@@ -295,7 +349,7 @@ test_rwlock (void)
/* Wait for the threads to terminate. */
for (i = 0; i < THREAD_COUNT; i++)
gl_thread_join (threads[i], NULL);
- rwlock_checker_done = 1;
+ set_atomic_int_value (&rwlock_checker_done, 1);
for (i = 0; i < THREAD_COUNT; i++)
gl_thread_join (checkerthreads[i], NULL);
check_accounts ();
@@ -356,12 +410,12 @@ reclock_mutator_thread (void *arg)
return NULL;
}
-static volatile int reclock_checker_done;
+static struct atomic_int reclock_checker_done;
static void *
reclock_checker_thread (void *arg)
{
- while (!reclock_checker_done)
+ while (get_atomic_int_value (&reclock_checker_done) == 0)
{
dbgprintf ("Checker %p before check lock\n", gl_thread_self_pointer ());
gl_recursive_lock_lock (my_reclock);
@@ -386,7 +440,8 @@ test_recursive_lock (void)
/* Initialization. */
for (i = 0; i < ACCOUNT_COUNT; i++)
account[i] = 1000;
- reclock_checker_done = 0;
+ init_atomic_int (&reclock_checker_done);
+ set_atomic_int_value (&reclock_checker_done, 0);
/* Spawn the threads. */
checkerthread = gl_thread_create (reclock_checker_thread, NULL);
@@ -396,7 +451,7 @@ test_recursive_lock (void)
/* Wait for the threads to terminate. */
for (i = 0; i < THREAD_COUNT; i++)
gl_thread_join (threads[i], NULL);
- reclock_checker_done = 1;
+ set_atomic_int_value (&reclock_checker_done, 1);
gl_thread_join (checkerthread, NULL);
check_accounts ();
}
|