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
|
package procfs
import (
"bytes"
"fmt"
"io/ioutil"
"os"
)
// Originally, this USER_HZ value was dynamically retrieved via a sysconf call
// which required cgo. However, that caused a lot of problems regarding
// cross-compilation. Alternatives such as running a binary to determine the
// value, or trying to derive it in some other way were all problematic. After
// much research it was determined that USER_HZ is actually hardcoded to 100 on
// all Go-supported platforms as of the time of this writing. This is why we
// decided to hardcode it here as well. It is not impossible that there could
// be systems with exceptions, but they should be very exotic edge cases, and
// in that case, the worst outcome will be two misreported metrics.
//
// See also the following discussions:
//
// - https://github.com/prometheus/node_exporter/issues/52
// - https://github.com/prometheus/procfs/pull/2
// - http://stackoverflow.com/questions/17410841/how-does-user-hz-solve-the-jiffy-scaling-issue
const userHZ = 100
// ProcStat provides status information about the process,
// read from /proc/[pid]/stat.
type ProcStat struct {
// The process ID.
PID int
// The filename of the executable.
Comm string
// The process state.
State string
// The PID of the parent of this process.
PPID int
// The process group ID of the process.
PGRP int
// The session ID of the process.
Session int
// The controlling terminal of the process.
TTY int
// The ID of the foreground process group of the controlling terminal of
// the process.
TPGID int
// The kernel flags word of the process.
Flags uint
// The number of minor faults the process has made which have not required
// loading a memory page from disk.
MinFlt uint
// The number of minor faults that the process's waited-for children have
// made.
CMinFlt uint
// The number of major faults the process has made which have required
// loading a memory page from disk.
MajFlt uint
// The number of major faults that the process's waited-for children have
// made.
CMajFlt uint
// Amount of time that this process has been scheduled in user mode,
// measured in clock ticks.
UTime uint
// Amount of time that this process has been scheduled in kernel mode,
// measured in clock ticks.
STime uint
// Amount of time that this process's waited-for children have been
// scheduled in user mode, measured in clock ticks.
CUTime uint
// Amount of time that this process's waited-for children have been
// scheduled in kernel mode, measured in clock ticks.
CSTime uint
// For processes running a real-time scheduling policy, this is the negated
// scheduling priority, minus one.
Priority int
// The nice value, a value in the range 19 (low priority) to -20 (high
// priority).
Nice int
// Number of threads in this process.
NumThreads int
// The time the process started after system boot, the value is expressed
// in clock ticks.
Starttime uint64
// Virtual memory size in bytes.
VSize int
// Resident set size in pages.
RSS int
fs FS
}
// NewStat returns the current status information of the process.
func (p Proc) NewStat() (ProcStat, error) {
f, err := os.Open(p.path("stat"))
if err != nil {
return ProcStat{}, err
}
defer f.Close()
data, err := ioutil.ReadAll(f)
if err != nil {
return ProcStat{}, err
}
var (
ignore int
s = ProcStat{PID: p.PID, fs: p.fs}
l = bytes.Index(data, []byte("("))
r = bytes.LastIndex(data, []byte(")"))
)
if l < 0 || r < 0 {
return ProcStat{}, fmt.Errorf(
"unexpected format, couldn't extract comm: %s",
data,
)
}
s.Comm = string(data[l+1 : r])
_, err = fmt.Fscan(
bytes.NewBuffer(data[r+2:]),
&s.State,
&s.PPID,
&s.PGRP,
&s.Session,
&s.TTY,
&s.TPGID,
&s.Flags,
&s.MinFlt,
&s.CMinFlt,
&s.MajFlt,
&s.CMajFlt,
&s.UTime,
&s.STime,
&s.CUTime,
&s.CSTime,
&s.Priority,
&s.Nice,
&s.NumThreads,
&ignore,
&s.Starttime,
&s.VSize,
&s.RSS,
)
if err != nil {
return ProcStat{}, err
}
return s, nil
}
// VirtualMemory returns the virtual memory size in bytes.
func (s ProcStat) VirtualMemory() int {
return s.VSize
}
// ResidentMemory returns the resident memory size in bytes.
func (s ProcStat) ResidentMemory() int {
return s.RSS * os.Getpagesize()
}
// StartTime returns the unix timestamp of the process in seconds.
func (s ProcStat) StartTime() (float64, error) {
stat, err := s.fs.NewStat()
if err != nil {
return 0, err
}
return float64(stat.BootTime) + (float64(s.Starttime) / userHZ), nil
}
// CPUTime returns the total CPU user and system time in seconds.
func (s ProcStat) CPUTime() float64 {
return float64(s.UTime+s.STime) / userHZ
}
|
