1 /*
   2  * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 
  27 
  28 package sun.misc;
  29 
  30 import java.util.Vector;
  31 import java.io.FileWriter;
  32 import java.io.File;
  33 import java.io.OutputStreamWriter;
  34 import java.io.Writer;
  35 
  36 /**
  37  * This class is intended to be a central place for the jdk to
  38  * log timing events of interest.  There is pre-defined event
  39  * of startTime, as well as a general
  40  * mechanism of setting arbitrary times in an array.
  41  * All unreserved times in the array can be used by callers
  42  * in application-defined situations.  The caller is responsible
  43  * for setting and getting all times and for doing whatever
  44  * analysis is interesting; this class is merely a central container
  45  * for those timing values.
  46  * Note that, due to the variables in this class being static,
  47  * use of particular time values by multiple applets will cause
  48  * confusing results.  For example, if plugin runs two applets
  49  * simultaneously, the initTime for those applets will collide
  50  * and the results may be undefined.
  51  * <P>
  52  * To automatically track startup performance in an app or applet,
  53  * use the command-line parameter sun.perflog as follows:<BR>
  54  *     -Dsun.perflog[=file:<filename>]
  55  * <BR>
  56  * where simply using the parameter with no value will enable output
  57  * to the console and a value of "file:<filename>" will cause
  58  * that given filename to be created and used for all output.
  59  * <P>
  60  * By default, times are measured using System.currentTimeMillis().  To use
  61  * System.nanoTime() instead, add the command-line parameter:<BR>
  62        -Dsun.perflog.nano=true
  63  * <BR>
  64  * <P>
  65  * <B>Warning: Use at your own risk!</B>
  66  * This class is intended for internal testing
  67  * purposes only and may be removed at any time.  More
  68  * permanent monitoring and profiling APIs are expected to be
  69  * developed for future releases and this class will cease to
  70  * exist once those APIs are in place.
  71  * @author Chet Haase
  72  */
  73 public class PerformanceLogger {
  74 
  75     // Timing values of global interest
  76     private static final int START_INDEX    = 0;    // VM start
  77     private static final int LAST_RESERVED  = START_INDEX;
  78 
  79     private static boolean perfLoggingOn = false;
  80     private static boolean useNanoTime = false;
  81     private static Vector<TimeData> times;
  82     private static String logFileName = null;
  83     private static Writer logWriter = null;
  84     private static long baseTime;
  85 
  86     static {
  87         String perfLoggingProp =
  88             java.security.AccessController.doPrivileged(
  89             new sun.security.action.GetPropertyAction("sun.perflog"));
  90         if (perfLoggingProp != null) {
  91             perfLoggingOn = true;
  92 
  93             // Check if we should use nanoTime
  94             String perfNanoProp =
  95                 java.security.AccessController.doPrivileged(
  96                 new sun.security.action.GetPropertyAction("sun.perflog.nano"));
  97             if (perfNanoProp != null) {
  98                 useNanoTime = true;
  99             }
 100 
 101             // Now, figure out what the user wants to do with the data
 102             if (perfLoggingProp.regionMatches(true, 0, "file:", 0, 5)) {
 103                 logFileName = perfLoggingProp.substring(5);
 104             }
 105             if (logFileName != null) {
 106                 if (logWriter == null) {
 107                     java.security.AccessController.doPrivileged(
 108                     new java.security.PrivilegedAction<Void>() {
 109                         public Void run() {
 110                             try {
 111                                 File logFile = new File(logFileName);
 112                                 logFile.createNewFile();
 113                                 logWriter = new FileWriter(logFile);
 114                             } catch (Exception e) {
 115                                 System.out.println(e + ": Creating logfile " +
 116                                                    logFileName +
 117                                                    ".  Log to console");
 118                             }
 119                             return null;
 120                         }
 121                     });
 122                 }
 123             }
 124             if (logWriter == null) {
 125                 logWriter = new OutputStreamWriter(System.out);
 126             }
 127         }
 128         times = new Vector<TimeData>(10);
 129         // Reserve predefined slots
 130         for (int i = 0; i <= LAST_RESERVED; ++i) {
 131             times.add(new TimeData("Time " + i + " not set", 0));
 132         }
 133     }
 134 
 135     /**
 136      * Returns status of whether logging is enabled or not.  This is
 137      * provided as a convenience method so that users do not have to
 138      * perform the same GetPropertyAction check as above to determine whether
 139      * to enable performance logging.
 140      */
 141     public static boolean loggingEnabled() {
 142         return perfLoggingOn;
 143     }
 144 
 145 
 146     /**
 147      * Internal class used to store time/message data together.
 148      */
 149     static class TimeData {
 150         String message;
 151         long time;
 152 
 153         TimeData(String message, long time) {
 154             this.message = message;
 155             this.time = time;
 156         }
 157 
 158         String getMessage() {
 159             return message;
 160         }
 161 
 162         long getTime() {
 163             return time;
 164         }
 165     }
 166 
 167     /**
 168      * Return the current time, in millis or nanos as appropriate
 169      */
 170     private static long getCurrentTime() {
 171         if (useNanoTime) {
 172             return System.nanoTime();
 173         } else {
 174             return System.currentTimeMillis();
 175         }
 176     }
 177 
 178     /**
 179      * Sets the start time.  Ideally, this is the earliest time available
 180      * during the startup of a Java applet or application.  This time is
 181      * later used to analyze the difference between the initial startup
 182      * time and other events in the system (such as an applet's init time).
 183      */
 184     public static void setStartTime(String message) {
 185         if (loggingEnabled()) {
 186             long nowTime = getCurrentTime();
 187             setStartTime(message, nowTime);
 188         }
 189     }
 190 
 191     /**
 192      * Sets the base time, output can then
 193      * be displayed as offsets from the base time;.
 194      */
 195     public static void setBaseTime(long time) {
 196         if (loggingEnabled()) {
 197             baseTime = time;
 198         }
 199     }
 200 
 201     /**
 202      * Sets the start time.
 203      * This version of the method is
 204      * given the time to log, instead of expecting this method to
 205      * get the time itself.  This is done in case the time was
 206      * recorded much earlier than this method was called.
 207      */
 208     public static void setStartTime(String message, long time) {
 209         if (loggingEnabled()) {
 210             times.set(START_INDEX, new TimeData(message, time));
 211         }
 212     }
 213 
 214     /**
 215      * Gets the start time, which should be the time when
 216      * the java process started, prior to the VM actually being
 217      * loaded.
 218      */
 219     public static long getStartTime() {
 220         if (loggingEnabled()) {
 221             return times.get(START_INDEX).getTime();
 222         } else {
 223             return 0;
 224         }
 225     }
 226 
 227     /**
 228      * Sets the value of a given time and returns the index of the
 229      * slot that that time was stored in.
 230      */
 231     public static int setTime(String message) {
 232         if (loggingEnabled()) {
 233             long nowTime = getCurrentTime();
 234             return setTime(message, nowTime);
 235         } else {
 236             return 0;
 237         }
 238     }
 239 
 240     /**
 241      * Sets the value of a given time and returns the index of the
 242      * slot that that time was stored in.
 243      * This version of the method is
 244      * given the time to log, instead of expecting this method to
 245      * get the time itself.  This is done in case the time was
 246      * recorded much earlier than this method was called.
 247      */
 248     public static int setTime(String message, long time) {
 249         if (loggingEnabled()) {
 250             // times is already synchronized, but we need to ensure that
 251             // the size used in times.set() is the same used when returning
 252             // the index of that operation.
 253             synchronized (times) {
 254                 times.add(new TimeData(message, time));
 255                 return (times.size() - 1);
 256             }
 257         } else {
 258             return 0;
 259         }
 260     }
 261 
 262     /**
 263      * Returns time at given index.
 264      */
 265     public static long getTimeAtIndex(int index) {
 266         if (loggingEnabled()) {
 267             return times.get(index).getTime();
 268         } else {
 269             return 0;
 270         }
 271     }
 272 
 273     /**
 274      * Returns message at given index.
 275      */
 276     public static String getMessageAtIndex(int index) {
 277         if (loggingEnabled()) {
 278             return times.get(index).getMessage();
 279         } else {
 280             return null;
 281         }
 282     }
 283 
 284     /**
 285      * Outputs all data to parameter-specified Writer object
 286      */
 287     public static void outputLog(Writer writer) {
 288         if (loggingEnabled()) {
 289             try {
 290                 synchronized(times) {
 291                     for (int i = 0; i < times.size(); ++i) {
 292                         TimeData td = times.get(i);
 293                         if (td != null) {
 294                             writer.write(i + " " + td.getMessage() + ": " +
 295                                          (td.getTime() - baseTime) + "\n");
 296 
 297                         }
 298                     }
 299                 }
 300                 writer.flush();
 301             } catch (Exception e) {
 302                 System.out.println(e + ": Writing performance log to " +
 303                                    writer);
 304             }
 305         }
 306     }
 307 
 308     /**
 309      * Outputs all data to whatever location the user specified
 310      * via sun.perflog command-line parameter.
 311      */
 312     public static void outputLog() {
 313         outputLog(logWriter);
 314     }
 315 }