1 /* 2 * Copyright (C) 2021 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 17 package com.android.internal.os; 18 19 import android.os.BatteryStats; 20 21 /** 22 * Implements a simple linear power model based on the assumption that the power consumer 23 * consumes a fixed current when it is used and no current when it is unused. 24 * 25 * <code>power = usageDuration * averagePower</code> 26 */ 27 public class UsageBasedPowerEstimator { 28 private static final double MILLIS_IN_HOUR = 1000.0 * 60 * 60; 29 private final double mAveragePowerMahPerMs; 30 UsageBasedPowerEstimator(double averagePowerMilliAmp)31 public UsageBasedPowerEstimator(double averagePowerMilliAmp) { 32 mAveragePowerMahPerMs = averagePowerMilliAmp / MILLIS_IN_HOUR; 33 } 34 isSupported()35 public boolean isSupported() { 36 return mAveragePowerMahPerMs != 0; 37 } 38 39 /** 40 * Given a {@link BatteryStats.Timer}, returns the accumulated duration. 41 */ calculateDuration(BatteryStats.Timer timer, long rawRealtimeUs, int statsType)42 public long calculateDuration(BatteryStats.Timer timer, long rawRealtimeUs, int statsType) { 43 return timer == null ? 0 : timer.getTotalTimeLocked(rawRealtimeUs, statsType) / 1000; 44 } 45 46 /** 47 * Given a duration in milliseconds, return the estimated power consumption. 48 */ calculatePower(long durationMs)49 public double calculatePower(long durationMs) { 50 return mAveragePowerMahPerMs * durationMs; 51 } 52 } 53