core/src/core/org/jnode/vm/memmgr/generational/GenGCStatsCounter.java - new-gc-algorithms in JNode

/*
 * $Id$
 *
 * Copyright (C) 2003-2009 JNode.org
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; If not, write to the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package org.jnode.vm.memmgr.generational;

import org.jnode.vm.memmgr.GCStatistics;

/**
 * 
 * @author loic
 *
 */
final class GenGCStatsCounter extends GCStatistics {

	private String title;
	private long lastDuration;
	private long lastPauseDuration;
	private long avgDuration;
	private long avgPauseDuration;
	private long lastExecutionDate;
	private long firstExecutionDate = -1L;
	private long nbExecutions = 0L;

	public GenGCStatsCounter(String title) {
		this.title = title;
	}
	
	public void addExecutionDuration(long duration) {
		long currentDate = currentMillis();
		lastDuration = duration;
		lastPauseDuration = lastExecutionDate - currentDate;
		avgDuration = computeAvg(lastDuration, avgDuration);
		avgPauseDuration = computeAvg(lastPauseDuration, avgPauseDuration);
		lastExecutionDate = currentDate;
		if (firstExecutionDate < 0L) {
			firstExecutionDate = currentDate;
		}
		nbExecutions++;
	}
	
	@Override
	public String toString() {
		return "--------------------\n\t" +
		 title + "--------------------\n" +
		 addString("last duration", lastDuration, "ms") +
		 addString("last pause duration", lastPauseDuration, "ms") +
		 addString("average duration", avgDuration, "ms") +
		 addString("average pause duration", avgPauseDuration, "ms") +
		 addString("last execution", currentMillis() - lastExecutionDate, "ms ago") +
		 addString("overhead", getOverhead()) +
		 addString("time executed", nbExecutions) + 
		 "--------------------\n";
	}

	private String addString(String property, long value) {
		return addString(property, value, "");
	}

	private String addString(String property, long value, String unit) {
        return property + ": " + value + " " + unit + "\n";
	}
	
	private long getOverhead() {
		return (100 * avgDuration) / (lastExecutionDate - firstExecutionDate);
	}

	private long currentMillis() {
        return GenGCStatistics.currentMillis();
	}
	
	private long computeAvg(long newValue, long previousAvg) {
		return (previousAvg * nbExecutions + newValue) / (nbExecutions + 1);
	}
}

1	/*
2	* $Id$
3	*
4	* Copyright (C) 2003-2009 JNode.org
5	*
6	* This library is free software; you can redistribute it and/or modify it
7	* under the terms of the GNU Lesser General Public License as published
8	* by the Free Software Foundation; either version 2.1 of the License, or
9	* (at your option) any later version.
10	*
11	* This library is distributed in the hope that it will be useful, but
12	* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13	* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
14	* License for more details.
15	*
16	* You should have received a copy of the GNU Lesser General Public License
17	* along with this library; If not, write to the Free Software Foundation, Inc.,
18	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
19	*/
20
21	package org.jnode.vm.memmgr.generational;
22
23	import org.jnode.vm.memmgr.GCStatistics;
24
25	/**
26	*
27	* @author loic
28	*
29	*/
30	final class GenGCStatsCounter extends GCStatistics {
31
32	private String title;
33	private long lastDuration;
34	private long lastPauseDuration;
35	private long avgDuration;
36	private long avgPauseDuration;
37	private long lastExecutionDate;
38	private long firstExecutionDate = -1L;
39	private long nbExecutions = 0L;
40
41	public GenGCStatsCounter(String title) {
42	this.title = title;
43	}
44
45	public void addExecutionDuration(long duration) {
46	long currentDate = currentMillis();
47	lastDuration = duration;
48	lastPauseDuration = lastExecutionDate - currentDate;
49	avgDuration = computeAvg(lastDuration, avgDuration);
50	avgPauseDuration = computeAvg(lastPauseDuration, avgPauseDuration);
51	lastExecutionDate = currentDate;
52	if (firstExecutionDate < 0L) {
53	firstExecutionDate = currentDate;
54	}
55	nbExecutions++;
56	}
57
58	@Override
59	public String toString() {
60	return "--------------------\n\t" +
61	title + "--------------------\n" +
62	addString("last duration", lastDuration, "ms") +
63	addString("last pause duration", lastPauseDuration, "ms") +
64	addString("average duration", avgDuration, "ms") +
65	addString("average pause duration", avgPauseDuration, "ms") +
66	addString("last execution", currentMillis() - lastExecutionDate, "ms ago") +
67	addString("overhead", getOverhead()) +
68	addString("time executed", nbExecutions) +
69	"--------------------\n";
70	}
71
72	private String addString(String property, long value) {
73	return addString(property, value, "");
74	}
75
76	private String addString(String property, long value, String unit) {
77	return property + ": " + value + " " + unit + "\n";
78	}
79
80	private long getOverhead() {
81	return (100 * avgDuration) / (lastExecutionDate - firstExecutionDate);
82	}
83
84	private long currentMillis() {
85	return GenGCStatistics.currentMillis();
86	}
87
88	private long computeAvg(long newValue, long previousAvg) {
89	return (previousAvg * nbExecutions + newValue) / (nbExecutions + 1);
90	}
91	}

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