Home | History | Annotate | Download | only in multiuser 
      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  */
     16 package android.multiuser;
     17 
     18 import android.os.Bundle;
     19 
     20 import java.util.ArrayList;
     21 import java.util.Collections;
     22 import java.util.concurrent.TimeUnit;
     23 
     24 public 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