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
|
/*
* Copyright (C) 2009, Christian Halstrick <christian.halstrick@sap.com>
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.util;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;
/**
* A simple stopwatch which measures elapsed CPU time of the current thread. CPU
* time is the time spent on executing your own code plus the time spent on
* executing operating system calls triggered by your application.
* <p>
* This stopwatch needs a VM which supports getting CPU Time information for the
* current thread. The static method createInstance() will take care to return
* only a new instance of this class if the VM is capable of returning CPU time.
*/
public class CPUTimeStopWatch {
private long start;
private static ThreadMXBean mxBean=ManagementFactory.getThreadMXBean();
/**
* use this method instead of the constructor to be sure that the underlying
* VM provides all features needed by this class.
*
* @return a new instance of {@link #CPUTimeStopWatch()} or
* <code>null</code> if the VM does not support getting CPU time
* information
*/
public static CPUTimeStopWatch createInstance() {
return mxBean.isCurrentThreadCpuTimeSupported() ? new CPUTimeStopWatch()
: null;
}
/**
* Starts the stopwatch. If the stopwatch is already started this will
* restart the stopwatch.
*/
public void start() {
start = mxBean.getCurrentThreadCpuTime();
}
/**
* Stops the stopwatch and return the elapsed CPU time in nanoseconds.
* Should be called only on started stopwatches.
*
* @return the elapsed CPU time in nanoseconds. When called on non-started
* stopwatches (either because {@link #start()} was never called or
* {@link #stop()} was called after the last call to
* {@link #start()}) this method will return 0.
*/
public long stop() {
long cpuTime = readout();
start = 0;
return cpuTime;
}
/**
* Return the elapsed CPU time in nanoseconds. In contrast to
* {@link #stop()} the stopwatch will continue to run after this call.
*
* @return the elapsed CPU time in nanoseconds. When called on non-started
* stopwatches (either because {@link #start()} was never called or
* {@link #stop()} was called after the last call to
* {@link #start()}) this method will return 0.
*/
public long readout() {
return (start == 0) ? 0 : mxBean.getCurrentThreadCpuTime() - start;
}
}
|
