projects/linux·blob master · refs

127 lines · 2.2 KiB

1// SPDX-License-Identifier: GPL-2.0
2#include <linux/init.h>
3#include <linux/kthread.h>
4#include <linux/hrtimer.h>
5#include <linux/fs.h>
6#include <linux/debugfs.h>
7#include <linux/export.h>
8#include <linux/spinlock.h>
9#include <asm/debug.h>
10
11static int ss_get(void *data, u64 *val)
12{
13 ktime_t start, finish;
14 int loops;
15 int cont;
16 DEFINE_RAW_SPINLOCK(ss_spin);
17
18 loops = 1000000;
19 cont = 1;
20
21 start = ktime_get();
22
23 while (cont) {
24 raw_spin_lock(&ss_spin);
25 loops--;
26 if (loops == 0)
27 cont = 0;
28 raw_spin_unlock(&ss_spin);
29 }
30
31 finish = ktime_get();
32
33 *val = ktime_us_delta(finish, start);
34
35 return 0;
36}
37
38DEFINE_DEBUGFS_ATTRIBUTE(fops_ss, ss_get, NULL, "%llu\n");
39
40
41
42struct spin_multi_state {
43 raw_spinlock_t lock;
44 atomic_t start_wait;
45 atomic_t enter_wait;
46 atomic_t exit_wait;
47 int loops;
48};
49
50struct spin_multi_per_thread {
51 struct spin_multi_state *state;
52 ktime_t start;
53};
54
55static int multi_other(void *data)
56{
57 int loops;
58 int cont;
59 struct spin_multi_per_thread *pt = data;
60 struct spin_multi_state *s = pt->state;
61
62 loops = s->loops;
63 cont = 1;
64
65 atomic_dec(&s->enter_wait);
66
67 while (atomic_read(&s->enter_wait))
68 ; /* spin */
69
70 pt->start = ktime_get();
71
72 atomic_dec(&s->start_wait);
73
74 while (atomic_read(&s->start_wait))
75 ; /* spin */
76
77 while (cont) {
78 raw_spin_lock(&s->lock);
79 loops--;
80 if (loops == 0)
81 cont = 0;
82 raw_spin_unlock(&s->lock);
83 }
84
85 atomic_dec(&s->exit_wait);
86 while (atomic_read(&s->exit_wait))
87 ; /* spin */
88 return 0;
89}
90
91static int multi_get(void *data, u64 *val)
92{
93 ktime_t finish;
94 struct spin_multi_state ms;
95 struct spin_multi_per_thread t1, t2;
96
97 ms.lock = __RAW_SPIN_LOCK_UNLOCKED("multi_get");
98 ms.loops = 1000000;
99
100 atomic_set(&ms.start_wait, 2);
101 atomic_set(&ms.enter_wait, 2);
102 atomic_set(&ms.exit_wait, 2);
103 t1.state = &ms;
104 t2.state = &ms;
105
106 kthread_run(multi_other, &t2, "multi_get");
107
108 multi_other(&t1);
109
110 finish = ktime_get();
111
112 *val = ktime_us_delta(finish, t1.start);
113
114 return 0;
115}
116
117DEFINE_DEBUGFS_ATTRIBUTE(fops_multi, multi_get, NULL, "%llu\n");
118
119static int __init spinlock_test(void)
120{
121 debugfs_create_file_unsafe("spin_single", S_IRUGO, mips_debugfs_dir, NULL,
122 &fops_ss);
123 debugfs_create_file_unsafe("spin_multi", S_IRUGO, mips_debugfs_dir, NULL,
124 &fops_multi);
125 return 0;
126}
127device_initcall(spinlock_test);