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
|
// @file timer.h
/* Copyright 2010 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects
* for all of the code used other than as permitted herein. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you do not
* wish to do so, delete this exception statement from your version. If you
* delete this exception statement from all source files in the program,
* then also delete it in the license file.
*/
#pragma once
#include "mongo/client/export_macros.h"
namespace mongo {
/**
* Time tracking object.
*
* Should be of reasonably high performance, though the implementations are platform-specific.
* Each platform provides a distinct implementation of the now() method, and sets the
* _countsPerSecond static field to the constant number of ticks per second that now() counts
* in. The maximum span measurable by the counter and convertible to microseconds is about 10
* trillion ticks. As long as there are fewer than 100 ticks per nanosecond, timer durations of
* 2.5 years will be supported. Since a typical tick duration will be under 10 per nanosecond,
* if not below 1 per nanosecond, this should not be an issue.
*/
class MONGO_CLIENT_API Timer /*copyable*/ {
public:
static const unsigned long long millisPerSecond = 1000;
static const unsigned long long microsPerSecond = 1000 * millisPerSecond;
static const unsigned long long nanosPerSecond = 1000 * microsPerSecond;
Timer() { reset(); }
int seconds() const { return (int)(micros() / 1000000); }
int millis() const { return (int)(micros() / 1000); }
int minutes() const { return seconds() / 60; }
/** Get the time interval and reset at the same time.
* @return time in milliseconds.
*/
inline int millisReset() {
unsigned long long nextNow = now();
unsigned long long deltaMicros =
((nextNow - _old) * microsPerSecond) / _countsPerSecond;
_old = nextNow;
return static_cast<int>(deltaMicros / 1000);
}
inline unsigned long long micros() const {
return ((now() - _old) * microsPerSecond) / _countsPerSecond;
}
inline void reset() { _old = now(); }
/**
* Internally, the timer counts platform-dependent ticks of some sort, and
* must then convert those ticks to microseconds and their ilk. This field
* stores the frequency of the platform-dependent counter.
*
* This value is initialized at program startup, and never changed after.
* It should be treated as private.
*/
static unsigned long long _countsPerSecond;
private:
inline unsigned long long now() const;
unsigned long long _old;
};
} // namespace mongo
#include "mongo/util/timer-inl.h"
|
