/* * Copyright (c) 2002, 2008, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.misc; import java.util.Vector; import java.io.FileWriter; import java.io.File; import java.io.OutputStreamWriter; import java.io.Writer; /** * This class is intended to be a central place for the jdk to * log timing events of interest. There is pre-defined event * of startTime, as well as a general * mechanism of setting aribtrary times in an array. * All unreserved times in the array can be used by callers * in application-defined situations. The caller is responsible * for setting and getting all times and for doing whatever * analysis is interesting; this class is merely a central container * for those timing values. * Note that, due to the variables in this class being static, * use of particular time values by multiple applets will cause * confusing results. For example, if plugin runs two applets * simultaneously, the initTime for those applets will collide * and the results may be undefined. *

* To automatically track startup performance in an app or applet, * use the command-line parameter sun.perflog as follows:
* -Dsun.perflog[=file:] *
* where simply using the parameter with no value will enable output * to the console and a value of "file:" will cause * that given filename to be created and used for all output. *

* By default, times are measured using System.currentTimeMillis(). To use * System.nanoTime() instead, add the command-line parameter:
-Dsun.perflog.nano=true *
*

* Warning: Use at your own risk! * This class is intended for internal testing * purposes only and may be removed at any time. More * permanent monitoring and profiling APIs are expected to be * developed for future releases and this class will cease to * exist once those APIs are in place. * @author Chet Haase */ public class PerformanceLogger { // Timing values of global interest private static final int START_INDEX = 0; // VM start private static final int LAST_RESERVED = START_INDEX; private static boolean perfLoggingOn = false; private static boolean useNanoTime = false; private static Vector times; private static String logFileName = null; private static Writer logWriter = null; private static long baseTime; static { String perfLoggingProp = java.security.AccessController.doPrivileged( new sun.security.action.GetPropertyAction("sun.perflog")); if (perfLoggingProp != null) { perfLoggingOn = true; // Check if we should use nanoTime String perfNanoProp = java.security.AccessController.doPrivileged( new sun.security.action.GetPropertyAction("sun.perflog.nano")); if (perfNanoProp != null) { useNanoTime = true; } // Now, figure out what the user wants to do with the data if (perfLoggingProp.regionMatches(true, 0, "file:", 0, 5)) { logFileName = perfLoggingProp.substring(5); } if (logFileName != null) { if (logWriter == null) { java.security.AccessController.doPrivileged( new java.security.PrivilegedAction() { public Void run() { try { File logFile = new File(logFileName); logFile.createNewFile(); logWriter = new FileWriter(logFile); } catch (Exception e) { System.out.println(e + ": Creating logfile " + logFileName + ". Log to console"); } return null; } }); } } if (logWriter == null) { logWriter = new OutputStreamWriter(System.out); } } times = new Vector(10); // Reserve predefined slots for (int i = 0; i <= LAST_RESERVED; ++i) { times.add(new TimeData("Time " + i + " not set", 0)); } } /** * Returns status of whether logging is enabled or not. This is * provided as a convenience method so that users do not have to * perform the same GetPropertyAction check as above to determine whether * to enable performance logging. */ public static boolean loggingEnabled() { return perfLoggingOn; } /** * Internal class used to store time/message data together. */ static class TimeData { String message; long time; TimeData(String message, long time) { this.message = message; this.time = time; } String getMessage() { return message; } long getTime() { return time; } } /** * Return the current time, in millis or nanos as appropriate */ private static long getCurrentTime() { if (useNanoTime) { return System.nanoTime(); } else { return System.currentTimeMillis(); } } /** * Sets the start time. Ideally, this is the earliest time available * during the startup of a Java applet or application. This time is * later used to analyze the difference between the initial startup * time and other events in the system (such as an applet's init time). */ public static void setStartTime(String message) { if (loggingEnabled()) { long nowTime = getCurrentTime(); setStartTime(message, nowTime); } } /** * Sets the base time, output can then * be displayed as offsets from the base time;. */ public static void setBaseTime(long time) { if (loggingEnabled()) { baseTime = time; } } /** * Sets the start time. * This version of the method is * given the time to log, instead of expecting this method to * get the time itself. This is done in case the time was * recorded much earlier than this method was called. */ public static void setStartTime(String message, long time) { if (loggingEnabled()) { times.set(START_INDEX, new TimeData(message, time)); } } /** * Gets the start time, which should be the time when * the java process started, prior to the VM actually being * loaded. */ public static long getStartTime() { if (loggingEnabled()) { return times.get(START_INDEX).getTime(); } else { return 0; } } /** * Sets the value of a given time and returns the index of the * slot that that time was stored in. */ public static int setTime(String message) { if (loggingEnabled()) { long nowTime = getCurrentTime(); return setTime(message, nowTime); } else { return 0; } } /** * Sets the value of a given time and returns the index of the * slot that that time was stored in. * This version of the method is * given the time to log, instead of expecting this method to * get the time itself. This is done in case the time was * recorded much earlier than this method was called. */ public static int setTime(String message, long time) { if (loggingEnabled()) { // times is already synchronized, but we need to ensure that // the size used in times.set() is the same used when returning // the index of that operation. synchronized (times) { times.add(new TimeData(message, time)); return (times.size() - 1); } } else { return 0; } } /** * Returns time at given index. */ public static long getTimeAtIndex(int index) { if (loggingEnabled()) { return times.get(index).getTime(); } else { return 0; } } /** * Returns message at given index. */ public static String getMessageAtIndex(int index) { if (loggingEnabled()) { return times.get(index).getMessage(); } else { return null; } } /** * Outputs all data to parameter-specified Writer object */ public static void outputLog(Writer writer) { if (loggingEnabled()) { try { synchronized(times) { for (int i = 0; i < times.size(); ++i) { TimeData td = times.get(i); if (td != null) { writer.write(i + " " + td.getMessage() + ": " + (td.getTime() - baseTime) + "\n"); } } } writer.flush(); } catch (Exception e) { System.out.println(e + ": Writing performance log to " + writer); } } } /** * Outputs all data to whatever location the user specified * via sun.perflog command-line parameter. */ public static void outputLog() { outputLog(logWriter); } }