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
|
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <asm/octeon/octeon.h>
#include <asm/octeon/cvmx-ciu-defs.h>
#include <asm/octeon/cvmx.h>
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#define TIMER_NUM 3
static bool reset_stats;
struct latency_info {
u64 io_interval;
u64 cpu_interval;
u64 timer_start1;
u64 timer_start2;
u64 max_latency;
u64 min_latency;
u64 latency_sum;
u64 average_latency;
u64 interrupt_cnt;
};
static struct latency_info li;
static struct dentry *dir;
static int show_latency(struct seq_file *m, void *v)
{
u64 cpuclk, avg, max, min;
struct latency_info curr_li = li;
cpuclk = octeon_get_clock_rate();
max = (curr_li.max_latency * 1000000000) / cpuclk;
min = (curr_li.min_latency * 1000000000) / cpuclk;
avg = (curr_li.latency_sum * 1000000000) / (cpuclk * curr_li.interrupt_cnt);
seq_printf(m, "cnt: %10lld, avg: %7lld ns, max: %7lld ns, min: %7lld ns\n",
curr_li.interrupt_cnt, avg, max, min);
return 0;
}
static int oct_ilm_open(struct inode *inode, struct file *file)
{
return single_open(file, show_latency, NULL);
}
static const struct file_operations oct_ilm_ops = {
.open = oct_ilm_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int reset_statistics(void *data, u64 value)
{
reset_stats = true;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(reset_statistics_ops, NULL, reset_statistics, "%llu\n");
static void init_debugfs(void)
{
dir = debugfs_create_dir("oct_ilm", 0);
debugfs_create_file("statistics", 0222, dir, NULL, &oct_ilm_ops);
debugfs_create_file("reset", 0222, dir, NULL, &reset_statistics_ops);
}
static void init_latency_info(struct latency_info *li, int startup)
{
/* interval in milli seconds after which the interrupt will
* be triggered
*/
int interval = 1;
if (startup) {
/* Calculating by the amounts io clock and cpu clock would
* increment in interval amount of ms
*/
li->io_interval = (octeon_get_io_clock_rate() * interval) / 1000;
li->cpu_interval = (octeon_get_clock_rate() * interval) / 1000;
}
li->timer_start1 = 0;
li->timer_start2 = 0;
li->max_latency = 0;
li->min_latency = (u64)-1;
li->latency_sum = 0;
li->interrupt_cnt = 0;
}
static void start_timer(int timer, u64 interval)
{
union cvmx_ciu_timx timx;
unsigned long flags;
timx.u64 = 0;
timx.s.one_shot = 1;
timx.s.len = interval;
raw_local_irq_save(flags);
li.timer_start1 = read_c0_cvmcount();
cvmx_write_csr(CVMX_CIU_TIMX(timer), timx.u64);
/* Read it back to force wait until register is written. */
timx.u64 = cvmx_read_csr(CVMX_CIU_TIMX(timer));
li.timer_start2 = read_c0_cvmcount();
raw_local_irq_restore(flags);
}
static irqreturn_t cvm_oct_ciu_timer_interrupt(int cpl, void *dev_id)
{
u64 last_latency;
u64 last_int_cnt;
if (reset_stats) {
init_latency_info(&li, 0);
reset_stats = false;
} else {
last_int_cnt = read_c0_cvmcount();
last_latency = last_int_cnt - (li.timer_start1 + li.cpu_interval);
li.interrupt_cnt++;
li.latency_sum += last_latency;
if (last_latency > li.max_latency)
li.max_latency = last_latency;
if (last_latency < li.min_latency)
li.min_latency = last_latency;
}
start_timer(TIMER_NUM, li.io_interval);
return IRQ_HANDLED;
}
static void disable_timer(int timer)
{
union cvmx_ciu_timx timx;
timx.s.one_shot = 0;
timx.s.len = 0;
cvmx_write_csr(CVMX_CIU_TIMX(timer), timx.u64);
/* Read it back to force immediate write of timer register*/
timx.u64 = cvmx_read_csr(CVMX_CIU_TIMX(timer));
}
static __init int oct_ilm_module_init(void)
{
int rc;
int irq = OCTEON_IRQ_TIMER0 + TIMER_NUM;
init_debugfs();
rc = request_irq(irq, cvm_oct_ciu_timer_interrupt, IRQF_NO_THREAD,
"oct_ilm", 0);
if (rc) {
WARN(1, "Could not acquire IRQ %d", irq);
goto err_irq;
}
init_latency_info(&li, 1);
start_timer(TIMER_NUM, li.io_interval);
return 0;
err_irq:
debugfs_remove_recursive(dir);
return rc;
}
static __exit void oct_ilm_module_exit(void)
{
disable_timer(TIMER_NUM);
debugfs_remove_recursive(dir);
free_irq(OCTEON_IRQ_TIMER0 + TIMER_NUM, 0);
}
module_exit(oct_ilm_module_exit);
module_init(oct_ilm_module_init);
MODULE_AUTHOR("Venkat Subbiah, Cavium");
MODULE_DESCRIPTION("Measures interrupt latency on Octeon chips.");
MODULE_LICENSE("GPL");
|
