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      1 /*
      2  * Copyright (C) 2015 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 com.android.internal.os;
     17 
     18 import android.os.BatteryStats;
     19 import android.util.Log;
     20 
     21 /**
     22  * Estimates WiFi power usage based on timers in BatteryStats.
     23  */
     24 public class WifiPowerEstimator extends PowerCalculator {
     25     private static final boolean DEBUG = BatteryStatsHelper.DEBUG;
     26     private static final String TAG = "WifiPowerEstimator";
     27     private final double mWifiPowerPerPacket;
     28     private final double mWifiPowerOn;
     29     private final double mWifiPowerScan;
     30     private final double mWifiPowerBatchScan;
     31     private long mTotalAppWifiRunningTimeMs = 0;
     32 
     33     public WifiPowerEstimator(PowerProfile profile) {
     34         mWifiPowerPerPacket = getWifiPowerPerPacket(profile);
     35         mWifiPowerOn = profile.getAveragePower(PowerProfile.POWER_WIFI_ON);
     36         mWifiPowerScan = profile.getAveragePower(PowerProfile.POWER_WIFI_SCAN);
     37         mWifiPowerBatchScan = profile.getAveragePower(PowerProfile.POWER_WIFI_BATCHED_SCAN);
     38     }
     39 
     40     /**
     41      * Return estimated power per Wi-Fi packet in mAh/packet where 1 packet = 2 KB.
     42      */
     43     private static double getWifiPowerPerPacket(PowerProfile profile) {
     44         final long WIFI_BPS = 1000000; // TODO: Extract average bit rates from system
     45         final double WIFI_POWER = profile.getAveragePower(PowerProfile.POWER_WIFI_ACTIVE)
     46                 / 3600;
     47         return WIFI_POWER / (((double)WIFI_BPS) / 8 / 2048);
     48     }
     49 
     50     @Override
     51     public void calculateApp(BatterySipper app, BatteryStats.Uid u, long rawRealtimeUs,
     52                              long rawUptimeUs, int statsType) {
     53         app.wifiRxPackets = u.getNetworkActivityPackets(BatteryStats.NETWORK_WIFI_RX_DATA,
     54                 statsType);
     55         app.wifiTxPackets = u.getNetworkActivityPackets(BatteryStats.NETWORK_WIFI_TX_DATA,
     56                 statsType);
     57         app.wifiRxBytes = u.getNetworkActivityBytes(BatteryStats.NETWORK_WIFI_RX_DATA,
     58                 statsType);
     59         app.wifiTxBytes = u.getNetworkActivityBytes(BatteryStats.NETWORK_WIFI_TX_DATA,
     60                 statsType);
     61 
     62         final double wifiPacketPower = (app.wifiRxPackets + app.wifiTxPackets)
     63                 * mWifiPowerPerPacket;
     64 
     65         app.wifiRunningTimeMs = u.getWifiRunningTime(rawRealtimeUs, statsType) / 1000;
     66         mTotalAppWifiRunningTimeMs += app.wifiRunningTimeMs;
     67         final double wifiLockPower = (app.wifiRunningTimeMs * mWifiPowerOn) / (1000*60*60);
     68 
     69         final long wifiScanTimeMs = u.getWifiScanTime(rawRealtimeUs, statsType) / 1000;
     70         final double wifiScanPower = (wifiScanTimeMs * mWifiPowerScan) / (1000*60*60);
     71 
     72         double wifiBatchScanPower = 0;
     73         for (int bin = 0; bin < BatteryStats.Uid.NUM_WIFI_BATCHED_SCAN_BINS; bin++) {
     74             final long batchScanTimeMs =
     75                     u.getWifiBatchedScanTime(bin, rawRealtimeUs, statsType) / 1000;
     76             final double batchScanPower = (batchScanTimeMs * mWifiPowerBatchScan) / (1000*60*60);
     77             wifiBatchScanPower += batchScanPower;
     78         }
     79 
     80         app.wifiPowerMah = wifiPacketPower + wifiLockPower + wifiScanPower + wifiBatchScanPower;
     81         if (DEBUG && app.wifiPowerMah != 0) {
     82             Log.d(TAG, "UID " + u.getUid() + ": power=" +
     83                     BatteryStatsHelper.makemAh(app.wifiPowerMah));
     84         }
     85     }
     86 
     87     @Override
     88     public void calculateRemaining(BatterySipper app, BatteryStats stats, long rawRealtimeUs,
     89                                    long rawUptimeUs, int statsType) {
     90         final long totalRunningTimeMs = stats.getGlobalWifiRunningTime(rawRealtimeUs, statsType)
     91                 / 1000;
     92         final double powerDrain = ((totalRunningTimeMs - mTotalAppWifiRunningTimeMs) * mWifiPowerOn)
     93                 / (1000*60*60);
     94         app.wifiRunningTimeMs = totalRunningTimeMs;
     95         app.wifiPowerMah = Math.max(0, powerDrain);
     96     }
     97 
     98     @Override
     99     public void reset() {
    100         mTotalAppWifiRunningTimeMs = 0;
    101     }
    102 }
    103