BasicPerformanceTest.java

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 * Copyright (c) 2013, Daniel Murphy
 * All rights reserved.
 * 
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 * 	  this list of conditions and the following disclaimer in the documentation
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/**
 * Created at 8:12:11 AM Jan 18, 2011
 */
package org.jbox2d.profile;

import java.util.ArrayList;
import java.util.Collections;

import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;
import org.jbox2d.common.MathUtils;

/**
 * @author Daniel Murphy
 */
public abstract class BasicPerformanceTest {
  public static enum ResultFormat {
    MILLISECONDS(1000000, "Milliseconds"), MICROSECONDS(1000, "Microseconds"), NANOSECONDS(1,
        "Nanoseconds");

    private final int divisor;
    private final String name;

    private ResultFormat(int divisor, String name) {
      assert (divisor != 0);
      this.divisor = divisor;
      this.name = name;
    }
  }

  private ResultFormat format = ResultFormat.MICROSECONDS;
  private final int numTests, iters, frames;
  protected final DescriptiveStatistics[] stats;
  private ArrayList<Integer> testOrder = new ArrayList<Integer>();

  public BasicPerformanceTest(int numTests, int iters, int frames) {
    this.numTests = numTests;
    this.iters = iters;
    this.frames = frames;
    stats = new DescriptiveStatistics[numTests];
    for (int i = 0; i < numTests; i++) {
      stats[i] = new DescriptiveStatistics(iters * frames + 1);
      testOrder.add(i);
    }
  }
  
  public void setFormat(ResultFormat format) {
    this.format = format;
  }

  public void go() {
    long prev, after;
    // warmup
    println("Warmup");
    int warmupIters = iters / 10;
    for (int i = 0; i < warmupIters; i++) {
      println(i * 100.0 / warmupIters + "%");
      Collections.shuffle(testOrder);
      for (int test = 0; test < numTests; test++) {
        setupTest(test);
      }
      for (int j = 0; j < frames; j++) {
        Collections.shuffle(testOrder);
        for (int test = 0; test < numTests; test++) {
          int runningTest = testOrder.get(test);
          preStep(runningTest);
          step(runningTest);
        }
      }
    }
    println("Testing");
    for (int i = 0; i < iters; i++) {
      println(i * 100.0 / iters + "%");
      for (int test = 0; test < numTests; test++) {
        setupTest(test);
      }
      for (int j = 0; j < frames; j++) {
        Collections.shuffle(testOrder);
        for (int test = 0; test < numTests; test++) {
          int runningTest = testOrder.get(test);
          preStep(runningTest);
          prev = System.nanoTime();
          step(runningTest);
          after = System.nanoTime();
          stats[runningTest].addValue((after - prev));
        }
      }
    }
    printResults();
  }

  public void printResults() {
    printf("%-20s%20s%20s%20s\n", "Test Name", format.name + " Avg", "StdDev", "95% Interval");
    for (int i = 0; i < numTests; i++) {
      double mean = stats[i].getMean() / format.divisor;
      double stddev = stats[i].getStandardDeviation() / format.divisor;
      double diff = 1.96 * stddev / MathUtils.sqrt(stats[i].getN());
      printf("%-20s%20.3f%20.3f  (%7.3f,%7.3f)\n", getTestName(i), mean, stddev, mean - diff, mean
          + diff);
    }
  }

  public void setupTest(int testNum) {}

  public void preStep(int testNum) {}

  public abstract void step(int testNum);

  public abstract String getTestName(int testNum);

  public int getFrames(int testNum) {
    return 0;
  }

  // override to change output
  public void println(String s) {
    System.out.println(s);
  }

  public void printf(String s, Object... args) {
    System.out.printf(s, args);
  }
}