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
|
/**
* @file nmi_timer_int.c
*
* @remark Copyright 2011 Advanced Micro Devices, Inc.
*
* @author Robert Richter <robert.richter@amd.com>
*/
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/oprofile.h>
#include <linux/perf_event.h>
#ifdef CONFIG_OPROFILE_NMI_TIMER
static DEFINE_PER_CPU(struct perf_event *, nmi_timer_events);
static int ctr_running;
static struct perf_event_attr nmi_timer_attr = {
.type = PERF_TYPE_HARDWARE,
.config = PERF_COUNT_HW_CPU_CYCLES,
.size = sizeof(struct perf_event_attr),
.pinned = 1,
.disabled = 1,
};
static void nmi_timer_callback(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
event->hw.interrupts = 0; /* don't throttle interrupts */
oprofile_add_sample(regs, 0);
}
static int nmi_timer_start_cpu(int cpu)
{
struct perf_event *event = per_cpu(nmi_timer_events, cpu);
if (!event) {
event = perf_event_create_kernel_counter(&nmi_timer_attr, cpu, NULL,
nmi_timer_callback, NULL);
if (IS_ERR(event))
return PTR_ERR(event);
per_cpu(nmi_timer_events, cpu) = event;
}
if (event && ctr_running)
perf_event_enable(event);
return 0;
}
static void nmi_timer_stop_cpu(int cpu)
{
struct perf_event *event = per_cpu(nmi_timer_events, cpu);
if (event && ctr_running)
perf_event_disable(event);
}
static int nmi_timer_cpu_notifier(struct notifier_block *b, unsigned long action,
void *data)
{
int cpu = (unsigned long)data;
switch (action) {
case CPU_DOWN_FAILED:
case CPU_ONLINE:
nmi_timer_start_cpu(cpu);
break;
case CPU_DOWN_PREPARE:
nmi_timer_stop_cpu(cpu);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block nmi_timer_cpu_nb = {
.notifier_call = nmi_timer_cpu_notifier
};
static int nmi_timer_start(void)
{
int cpu;
get_online_cpus();
ctr_running = 1;
for_each_online_cpu(cpu)
nmi_timer_start_cpu(cpu);
put_online_cpus();
return 0;
}
static void nmi_timer_stop(void)
{
int cpu;
get_online_cpus();
for_each_online_cpu(cpu)
nmi_timer_stop_cpu(cpu);
ctr_running = 0;
put_online_cpus();
}
static void nmi_timer_shutdown(void)
{
struct perf_event *event;
int cpu;
cpu_notifier_register_begin();
__unregister_cpu_notifier(&nmi_timer_cpu_nb);
for_each_possible_cpu(cpu) {
event = per_cpu(nmi_timer_events, cpu);
if (!event)
continue;
perf_event_disable(event);
per_cpu(nmi_timer_events, cpu) = NULL;
perf_event_release_kernel(event);
}
cpu_notifier_register_done();
}
static int nmi_timer_setup(void)
{
int cpu, err;
u64 period;
/* clock cycles per tick: */
period = (u64)cpu_khz * 1000;
do_div(period, HZ);
nmi_timer_attr.sample_period = period;
cpu_notifier_register_begin();
err = __register_cpu_notifier(&nmi_timer_cpu_nb);
if (err)
goto out;
/* can't attach events to offline cpus: */
for_each_online_cpu(cpu) {
err = nmi_timer_start_cpu(cpu);
if (err) {
cpu_notifier_register_done();
nmi_timer_shutdown();
return err;
}
}
out:
cpu_notifier_register_done();
return err;
}
int __init op_nmi_timer_init(struct oprofile_operations *ops)
{
int err = 0;
err = nmi_timer_setup();
if (err)
return err;
nmi_timer_shutdown(); /* only check, don't alloc */
ops->create_files = NULL;
ops->setup = nmi_timer_setup;
ops->shutdown = nmi_timer_shutdown;
ops->start = nmi_timer_start;
ops->stop = nmi_timer_stop;
ops->cpu_type = "timer";
printk(KERN_INFO "oprofile: using NMI timer interrupt.\n");
return 0;
}
#endif
|
