/*
* This file is part of the Jikes RVM project (http://jikesrvm.org).
*
* This file is licensed to You under the Eclipse Public License (EPL);
* You may not use this file except in compliance with the License. You
* may obtain a copy of the License at
*
* http://www.opensource.org/licenses/eclipse-1.0.php
*
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.
*/
package org.jikesrvm.adaptive.recompilation.instrumentation;
import org.jikesrvm.adaptive.util.AOSOptions;
import org.vmmagic.pragma.Entrypoint;
import org.vmmagic.pragma.Uninterruptible;
/**
* Contains necessary infrastructure to perform counter-based
* sampling used with the instrumentation sampling code (PLDI'01)
* (see InstrumentationSamplingFramework)
* */
@Uninterruptible
public final class CounterBasedSampling {
static final boolean DEBUG = false;
/**
* Holds the value that is used to reset the global counter after
* a sample is taken.
*/
@Entrypoint
static int resetValue = 100;
/**
* The global counter.
*/
@Entrypoint
static int globalCounter = resetValue;
/**
* Initializes counter based sampling. Called when the VM boots.
*
* @param options the options for the AOS (and therefore also
* counter-based sampling)
*/
public static void boot(AOSOptions options) {
// Initialize the counter values
resetValue = options.COUNTER_BASED_SAMPLE_INTERVAL - 1;
globalCounter = resetValue;
}
}