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
|
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include "power.h"
/* XXX Is this exposed through RAPL? */
int power_init(struct power *power)
{
char buf[4096];
int fd, len;
memset(power, 0, sizeof(*power));
fd = open("/sys/kernel/debug/dri/0/i915_energy_uJ", 0);
if (fd < 0)
return power->error = errno;
len = read(fd, buf, sizeof(buf));
close(fd);
if (len < 0)
return power->error = errno;
return 0;
}
static uint64_t file_to_u64(const char *path)
{
char buf[4096];
int fd, len;
fd = open(path, 0);
if (fd < 0)
return 0;
len = read(fd, buf, sizeof(buf)-1);
close(fd);
if (len < 0)
return 0;
buf[len] = '\0';
return strtoull(buf, 0, 0);
}
static uint64_t clock_ms_to_u64(void)
{
struct timespec tv;
if (clock_gettime(CLOCK_MONOTONIC, &tv) < 0)
return 0;
return (uint64_t)tv.tv_sec * 1000 + tv.tv_nsec / 1000000;
}
int power_update(struct power *power)
{
struct power_stat *s = &power->stat[power->count++&1];
struct power_stat *d = &power->stat[power->count&1];
uint64_t d_time;
if (power->error)
return power->error;
s->energy = file_to_u64("/sys/kernel/debug/dri/0/i915_energy_uJ");
s->timestamp = clock_ms_to_u64();
if (power->count == 1)
return EAGAIN;
d_time = s->timestamp - d->timestamp;
if (d_time < 1200) { /* HW sample rate seems to be stable ~1Hz */
power->count--;
return power->count <= 1 ? EAGAIN : 0;
}
power->power_mW = (s->energy - d->energy) / d_time;
power->new_sample = 1;
return 0;
}
|
