1 #include <linux/init.h>
2 #include <linux/kthread.h>
3 #include <linux/hrtimer.h>
4 #include <linux/fs.h>
5 #include <linux/debugfs.h>
6 #include <linux/export.h>
7 #include <linux/spinlock.h>
8
9
ss_get(void * data,u64 * val)10 static int ss_get(void *data, u64 *val)
11 {
12 ktime_t start, finish;
13 int loops;
14 int cont;
15 DEFINE_RAW_SPINLOCK(ss_spin);
16
17 loops = 1000000;
18 cont = 1;
19
20 start = ktime_get();
21
22 while (cont) {
23 raw_spin_lock(&ss_spin);
24 loops--;
25 if (loops == 0)
26 cont = 0;
27 raw_spin_unlock(&ss_spin);
28 }
29
30 finish = ktime_get();
31
32 *val = ktime_us_delta(finish, start);
33
34 return 0;
35 }
36
37 DEFINE_SIMPLE_ATTRIBUTE(fops_ss, ss_get, NULL, "%llu\n");
38
39
40
41 struct spin_multi_state {
42 raw_spinlock_t lock;
43 atomic_t start_wait;
44 atomic_t enter_wait;
45 atomic_t exit_wait;
46 int loops;
47 };
48
49 struct spin_multi_per_thread {
50 struct spin_multi_state *state;
51 ktime_t start;
52 };
53
multi_other(void * data)54 static int multi_other(void *data)
55 {
56 int loops;
57 int cont;
58 struct spin_multi_per_thread *pt = data;
59 struct spin_multi_state *s = pt->state;
60
61 loops = s->loops;
62 cont = 1;
63
64 atomic_dec(&s->enter_wait);
65
66 while (atomic_read(&s->enter_wait))
67 ; /* spin */
68
69 pt->start = ktime_get();
70
71 atomic_dec(&s->start_wait);
72
73 while (atomic_read(&s->start_wait))
74 ; /* spin */
75
76 while (cont) {
77 raw_spin_lock(&s->lock);
78 loops--;
79 if (loops == 0)
80 cont = 0;
81 raw_spin_unlock(&s->lock);
82 }
83
84 atomic_dec(&s->exit_wait);
85 while (atomic_read(&s->exit_wait))
86 ; /* spin */
87 return 0;
88 }
89
multi_get(void * data,u64 * val)90 static int multi_get(void *data, u64 *val)
91 {
92 ktime_t finish;
93 struct spin_multi_state ms;
94 struct spin_multi_per_thread t1, t2;
95
96 ms.lock = __RAW_SPIN_LOCK_UNLOCKED("multi_get");
97 ms.loops = 1000000;
98
99 atomic_set(&ms.start_wait, 2);
100 atomic_set(&ms.enter_wait, 2);
101 atomic_set(&ms.exit_wait, 2);
102 t1.state = &ms;
103 t2.state = &ms;
104
105 kthread_run(multi_other, &t2, "multi_get");
106
107 multi_other(&t1);
108
109 finish = ktime_get();
110
111 *val = ktime_us_delta(finish, t1.start);
112
113 return 0;
114 }
115
116 DEFINE_SIMPLE_ATTRIBUTE(fops_multi, multi_get, NULL, "%llu\n");
117
118
119 extern struct dentry *mips_debugfs_dir;
spinlock_test(void)120 static int __init spinlock_test(void)
121 {
122 struct dentry *d;
123
124 if (!mips_debugfs_dir)
125 return -ENODEV;
126
127 d = debugfs_create_file("spin_single", S_IRUGO,
128 mips_debugfs_dir, NULL,
129 &fops_ss);
130 if (!d)
131 return -ENOMEM;
132
133 d = debugfs_create_file("spin_multi", S_IRUGO,
134 mips_debugfs_dir, NULL,
135 &fops_multi);
136 if (!d)
137 return -ENOMEM;
138
139 return 0;
140 }
141 device_initcall(spinlock_test);
142