1/* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16package android.multiuser; 17 18import android.os.Bundle; 19 20import java.util.ArrayList; 21import java.util.Collections; 22import java.util.concurrent.TimeUnit; 23 24public class BenchmarkResults { 25 private final ArrayList<Long> mResults = new ArrayList<>(); 26 27 public void addDuration(long duration) { 28 mResults.add(TimeUnit.NANOSECONDS.toMillis(duration)); 29 } 30 31 public Bundle getStatsToReport() { 32 final Bundle stats = new Bundle(); 33 stats.putDouble("Mean (ms)", mean()); 34 return stats; 35 } 36 37 public Bundle getStatsToLog() { 38 final Bundle stats = new Bundle(); 39 stats.putDouble("Mean (ms)", mean()); 40 stats.putDouble("Median (ms)", median()); 41 stats.putDouble("Sigma (ms)", standardDeviation()); 42 return stats; 43 } 44 45 public ArrayList<Long> getAllDurations() { 46 return mResults; 47 } 48 49 private double mean() { 50 final int size = mResults.size(); 51 long sum = 0; 52 for (int i = 0; i < size; ++i) { 53 sum += mResults.get(i); 54 } 55 return (double) sum / size; 56 } 57 58 private double median() { 59 final int size = mResults.size(); 60 if (size == 0) { 61 return 0f; 62 } 63 Collections.sort(mResults); 64 final int idx = size / 2; 65 return size % 2 == 0 66 ? (double) (mResults.get(idx) + mResults.get(idx - 1)) / 2 67 : mResults.get(idx); 68 } 69 70 private double standardDeviation() { 71 final int size = mResults.size(); 72 if (size == 0) { 73 return 0f; 74 } 75 final double mean = mean(); 76 double sd = 0; 77 for (int i = 0; i < size; ++i) { 78 double diff = mResults.get(i) - mean; 79 sd += diff * diff; 80 } 81 return Math.sqrt(sd / size); 82 } 83} 84