Perfometer.java

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/*
 * Javolution - Java(TM) Solution for Real-Time and Embedded Systems
 * Copyright (C) 2012 - Javolution (http://javolution.org/)
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software is
 * freely granted, provided that this notice is preserved.
 */
package javolution.test;
 
import javolution.context.LogContext;
import javolution.lang.Configurable;
import javolution.lang.MathLib;
import javolution.text.TextBuilder;
import javolution.util.FastTable;
 
public abstract class Perfometer<T> {
 
    public static final Configurable<Integer> DURATION_MS = new Configurable<Integer>() {
 
        @Override
        public String getName() { // Requires since there are multiple configurable fields.
            return this.getClass().getEnclosingClass().getName()
                    + "#DURATION_MS";
        }
 
        @Override
        protected Integer getDefault() {
            return 1000;
        }
 
    };
    public static final Configurable<Boolean> SKIP = new Configurable<Boolean>() {
 
        @Override
        public String getName() { // Requires since there are multiple configurable fields.
            return this.getClass().getEnclosingClass().getName() + "#SKIP";
        }
 
        @Override
        protected Boolean getDefault() {
            return false;
        }
    };
 
    private final String description;
    private T input;
    private long[] times; // Nano-Seconds.
 
    public Perfometer(String description) {
        this.description = description;
    }
 
    public double getAvgTimeInSeconds() {
        if (times == null) return Double.NaN;
        long sum = 0;
        for (long time : times) {
            sum += time;
        }
        return sum / 1e9 / times.length;
    }
 
    public String getDescription() {
        return description;
    }
 
    public T getInput() {
        return input;
    }
 
    public int getNbrOfIterations() {
        return (times != null) ? times.length : 0;
    }
 
    public double[] getTimesInSeconds() {
        if (times == null) return new double[0];
        double[] timesSec = new double[times.length];
        for (int i=0; i < times.length; i++) {
            timesSec[i] = times[i] / 1e9;
        }
        return timesSec;
    }
 
    public Perfometer<T> measure(T input, int nbrOfIterations) {
        if (SKIP.get()) return this; // Skip.
        this.input = input;
        this.times = new long[nbrOfIterations];
        long[] calibrations = longArray(nbrOfIterations, Long.MAX_VALUE);
        long[] measures = longArray(nbrOfIterations, Long.MAX_VALUE);
        try {
            long exitTime = System.currentTimeMillis() + DURATION_MS.get();
            do {
                // Calibration.
                initialize();
                for (int i = 0; i < nbrOfIterations; i++) {
                    long start = System.nanoTime();
                    run(false);
                    long time = System.nanoTime() - start;
                    calibrations[i] = MathLib.min(calibrations[i], time);
                }
                // Measurement.
                initialize();
                for (int i = 0; i < nbrOfIterations; i++) {
                    long start = System.nanoTime();
                    run(true);
                    long time = System.nanoTime() - start;
                    measures[i] = MathLib.min(measures[i], time);
                }
            } while (System.currentTimeMillis() < exitTime);
            for (int i = 0; i < nbrOfIterations; i++) {
                times[i] = measures[i] - calibrations[i];
            }
            return this;
        } catch (Exception error) {
            throw new RuntimeException("Perfometer Exception", error);
        }
    }
 
    public void print() {
        if (Perfometer.SKIP.get()) return;
        TextBuilder txt = new TextBuilder();
        txt.append(description).append(" (").append(getNbrOfIterations())
                .append(") for ").append(input).append(": ");
        while (txt.length() < 80)
            txt.append(' ');
        txt.append(getAvgTimeInSeconds() * 1E9, 8, false, true); // Nano-Seconds.
        txt.append(" ns (avg), ");
        txt.append(getWCETinSeconds() * 1E9, 8, false, true); // Nano-Seconds.
        txt.append(" ns (wcet#").append(getWorstCaseNumber()).append(")");
        LogContext.info(txt);
    }
 
    public void printDetails() {
        if (Perfometer.SKIP.get()) return;
        FastTable<Long> measurements = new FastTable<Long>();
        for (long time : times)
            measurements.add(time);
        LogContext.debug(measurements);
    }
 
    public double getWCETinSeconds() {
        if (times == null) return Double.NaN;
        long wcet = 0;
        for (long time : times) {
            if (time > wcet) wcet = time;
        }
        return wcet / 1e9;
    }
 
    public int getWorstCaseNumber() {
        if (times == null) return -1;
        long wcet = 0;
        int j = -1;
        for (int i=0; i < times.length; i++) {
            if (times[i] > wcet) {
                wcet = times[i];
                j = i;   
            }
        }
        return j;
    }
 
    protected abstract void initialize() throws Exception;
 
    protected abstract void run(boolean measure) throws Exception;
 
    protected void validate() {}
 
    private long[] longArray(int length, long initialValue) {
        long[] array = new long[length];
        for (int i = 0; i < length; i++)
            array[i] = initialValue;
        return array;
    }
}