001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm.adaptive.controller;
014    
015    import org.jikesrvm.classloader.NormalMethod;
016    import org.jikesrvm.compilers.common.CompiledMethod;
017    
018    /**
019     * A recompilation choice represents an action (or a set of actions)
020     * that can be considered by the controller's analytic model.
021     */
022    abstract class RecompilationChoice {
023    
024      //--- Interface ---
025    
026      /**
027       * What is the cost of selecting this recompilation choice
028       *
029       * @param meth The method being considered for recompilation.
030       * @return The expected cost of exeuting this recompilation choice
031       */
032      abstract double getCost(NormalMethod meth);
033    
034      /**
035       * What is the benefit of executing this recompilation choice, given
036       * the estimated future time for the method if nothing changes?
037       *
038       * @param prevCompiler The previous compiler
039       * @param futureExecutionTime The expected future execution time of
040       *        the method if left running with the previous compiler.
041       * @return The expected future execution time if this choice were selected
042       */
043      abstract double getFutureExecutionTime(int prevCompiler, double futureExecutionTime);
044    
045      /**
046       * Return a controller plan that will start this recompilation choice
047       * in action
048       *
049       * @param cmpMethod The method in question
050       * @param prevCompiler The previous compiler
051       * @param prevTimeFormethod The estimated future time had nothing been done
052       * @param bestActionTime The estimated total time implementing this choice
053       * @param bestCost The estimated compilation cost implementing this choice
054       * @return The controller plan implementing this recompilation choice
055       */
056      abstract ControllerPlan makeControllerPlan(CompiledMethod cmpMethod, int prevCompiler, double prevTimeFormethod,
057                                                    double bestActionTime, double bestCost);
058    
059    }
060    
061    
062    
063    
064    
065    
066