1 /*
   2  * Copyright (c) 2014, 2015, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package jdk.vm.ci.common;
  24 
  25 import java.util.concurrent.atomic.AtomicInteger;
  26 
  27 /**
  28  * A facility for timing a step in the runtime initialization sequence. This is independent from all
  29  * other JVMCI code so as to not perturb the initialization sequence. It is enabled by setting the
  30  * {@code "jvmci.inittimer"} system property to {@code "true"}.
  31  */
  32 public final class InitTimer implements AutoCloseable {
  33     private final String name;
  34     private final long start;
  35 
  36     private InitTimer(String name) {
  37         int n = nesting.getAndIncrement();
  38         if (n == 0) {
  39             initializingThread = Thread.currentThread();
  40             System.out.println("INITIALIZING THREAD: " + initializingThread);
  41         } else {
  42             assert Thread.currentThread() == initializingThread : Thread.currentThread() + " != " + initializingThread;
  43         }
  44         this.name = name;
  45         this.start = System.currentTimeMillis();
  46         System.out.println("START: " + SPACES.substring(0, n * 2) + name);
  47     }
  48 
  49     @SuppressFBWarnings(value = "ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD", justification = "only the initializing thread accesses this field")
  50     public void close() {
  51         final long end = System.currentTimeMillis();
  52         int n = nesting.decrementAndGet();
  53         System.out.println(" DONE: " + SPACES.substring(0, n * 2) + name + " [" + (end - start) + " ms]");
  54         if (n == 0) {
  55             initializingThread = null;
  56         }
  57     }
  58 
  59     public static InitTimer timer(String name) {
  60         return ENABLED ? new InitTimer(name) : null;
  61     }
  62 
  63     public static InitTimer timer(String name, Object suffix) {
  64         return ENABLED ? new InitTimer(name + suffix) : null;
  65     }
  66 
  67     /**
  68      * Specifies if initialization timing is enabled. Note: This property cannot use
  69      * {@code HotSpotJVMCIRuntime.Option} since that class is not visible from this package.
  70      */
  71     private static final boolean ENABLED = Boolean.getBoolean("jvmci.InitTimer");
  72 
  73     public static final AtomicInteger nesting = ENABLED ? new AtomicInteger() : null;
  74     public static final String SPACES = "                                            ";
  75 
  76     /**
  77      * Used to assert the invariant that all related initialization happens on the same thread.
  78      */
  79     static Thread initializingThread;
  80 }