01: /*
02: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
03: *
04: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
05: *
06: * The contents of this file are subject to the terms of either the GNU
07: * General Public License Version 2 only ("GPL") or the Common
08: * Development and Distribution License("CDDL") (collectively, the
09: * "License"). You may not use this file except in compliance with the
10: * License. You can obtain a copy of the License at
11: * http://www.netbeans.org/cddl-gplv2.html
12: * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
13: * specific language governing permissions and limitations under the
14: * License. When distributing the software, include this License Header
15: * Notice in each file and include the License file at
16: * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
17: * particular file as subject to the "Classpath" exception as provided
18: * by Sun in the GPL Version 2 section of the License file that
19: * accompanied this code. If applicable, add the following below the
20: * License Header, with the fields enclosed by brackets [] replaced by
21: * your own identifying information:
22: * "Portions Copyrighted [year] [name of copyright owner]"
23: *
24: * Contributor(s):
25: * The Original Software is NetBeans. The Initial Developer of the Original
26: * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
27: * Microsystems, Inc. All Rights Reserved.
28: *
29: * If you wish your version of this file to be governed by only the CDDL
30: * or only the GPL Version 2, indicate your decision by adding
31: * "[Contributor] elects to include this software in this distribution
32: * under the [CDDL or GPL Version 2] license." If you do not indicate a
33: * single choice of license, a recipient has the option to distribute
34: * your version of this file under either the CDDL, the GPL Version 2 or
35: * to extend the choice of license to its licensees as provided above.
36: * However, if you add GPL Version 2 code and therefore, elected the GPL
37: * Version 2 license, then the option applies only if the new code is
38: * made subject to such option by the copyright holder.
39: */
40:
41: package org.netbeans.lib.profiler.server.system;
42:
43: import java.lang.management.ManagementFactory;
44: import java.lang.management.ThreadMXBean;
45:
46: /**
47: * Provides methods for obtaining various high-resolution system times.
48: * A version for JDK 1.5
49: *
50: * @author Misha Dmitriev
51: */
52: public class Timers {
53: //~ Static fields/initializers -----------------------------------------------------------------------------------------------
54:
55: private static ThreadMXBean mxbean;
56:
57: //~ Methods ------------------------------------------------------------------------------------------------------------------
58:
59: /**
60: * "counts" instead of nanoseconds in this method are for compatibility with the previous
61: * versions of JFluid, that call a native method for system timer, which, in turn, returns
62: * the result in sub-microsecond "counts" on Windows.
63: */
64: public static long getCurrentTimeInCounts() {
65: return System.nanoTime();
66: }
67:
68: public static long getNoOfCountsInSecond() {
69: return 1000000000;
70: }
71:
72: public static native long getThreadCPUTimeInNanos();
73:
74: /**
75: * This is relevant only on Solaris. By default, the resolution of the thread local CPU timer is 10 ms. If we enable
76: * micro state accounting, it enables significantly (but possibly at a price of some overhead). So I turn it on only
77: * when thread CPU timestamps are really collected.
78: */
79: public static native void enableMicrostateAccounting(boolean v);
80:
81: /** Should be called at earliest possible time */
82: public static void initialize() {
83: mxbean = ManagementFactory.getThreadMXBean();
84: getThreadCPUTimeInNanos();
85: }
86:
87: /**
88: * WORKS ONLY ON UNIX, calls nanosleep(). On Solaris, this is more precise than the built-in Thread.sleep() call
89: * implementation that, at least in JDK 1.4.2, goes to select(3C). On Linux, it should be more precise, but it
90: * turns out that nanosleep() in this OS, at least in version 7.3 that I tested, has a resolution of at least 20ms.
91: * This seems to be a known issue; hopefully they fix it in future.
92: */
93: public static native void osSleep(int ns);
94: }
|