/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.internal.os;
import android.os.BatteryStats;
import android.util.Log;
/**
* Estimates WiFi power usage based on timers in BatteryStats.
*/
public class WifiPowerEstimator extends PowerCalculator {
private static final boolean DEBUG = BatteryStatsHelper.DEBUG;
private static final String TAG = "WifiPowerEstimator";
private final double mWifiPowerPerPacket;
private final double mWifiPowerOn;
private final double mWifiPowerScan;
private final double mWifiPowerBatchScan;
private long mTotalAppWifiRunningTimeMs = 0;
public WifiPowerEstimator(PowerProfile profile) {
mWifiPowerPerPacket = getWifiPowerPerPacket(profile);
mWifiPowerOn = profile.getAveragePower(PowerProfile.POWER_WIFI_ON);
mWifiPowerScan = profile.getAveragePower(PowerProfile.POWER_WIFI_SCAN);
mWifiPowerBatchScan = profile.getAveragePower(PowerProfile.POWER_WIFI_BATCHED_SCAN);
}
/**
* Return estimated power (in mAs) of sending a byte with the Wi-Fi radio.
*/
private static double getWifiPowerPerPacket(PowerProfile profile) {
final long WIFI_BPS = 1000000; // TODO: Extract average bit rates from system
final double WIFI_POWER = profile.getAveragePower(PowerProfile.POWER_WIFI_ACTIVE)
/ 3600;
return (WIFI_POWER / (((double)WIFI_BPS) / 8 / 2048)) / (60*60);
}
@Override
public void calculateApp(BatterySipper app, BatteryStats.Uid u, long rawRealtimeUs,
long rawUptimeUs, int statsType) {
app.wifiRxPackets = u.getNetworkActivityPackets(BatteryStats.NETWORK_WIFI_RX_DATA,
statsType);
app.wifiTxPackets = u.getNetworkActivityPackets(BatteryStats.NETWORK_WIFI_TX_DATA,
statsType);
app.wifiRxBytes = u.getNetworkActivityBytes(BatteryStats.NETWORK_WIFI_RX_DATA,
statsType);
app.wifiTxBytes = u.getNetworkActivityBytes(BatteryStats.NETWORK_WIFI_TX_DATA,
statsType);
final double wifiPacketPower = (app.wifiRxPackets + app.wifiTxPackets)
* mWifiPowerPerPacket;
app.wifiRunningTimeMs = u.getWifiRunningTime(rawRealtimeUs, statsType) / 1000;
mTotalAppWifiRunningTimeMs += app.wifiRunningTimeMs;
final double wifiLockPower = (app.wifiRunningTimeMs * mWifiPowerOn) / (1000*60*60);
final long wifiScanTimeMs = u.getWifiScanTime(rawRealtimeUs, statsType) / 1000;
final double wifiScanPower = (wifiScanTimeMs * mWifiPowerScan) / (1000*60*60);
double wifiBatchScanPower = 0;
for (int bin = 0; bin < BatteryStats.Uid.NUM_WIFI_BATCHED_SCAN_BINS; bin++) {
final long batchScanTimeMs =
u.getWifiBatchedScanTime(bin, rawRealtimeUs, statsType) / 1000;
final double batchScanPower = (batchScanTimeMs * mWifiPowerBatchScan) / (1000*60*60);
wifiBatchScanPower += batchScanPower;
}
app.wifiPowerMah = wifiPacketPower + wifiLockPower + wifiScanPower + wifiBatchScanPower;
if (DEBUG && app.wifiPowerMah != 0) {
Log.d(TAG, "UID " + u.getUid() + ": power=" +
BatteryStatsHelper.makemAh(app.wifiPowerMah));
}
}
@Override
public void calculateRemaining(BatterySipper app, BatteryStats stats, long rawRealtimeUs,
long rawUptimeUs, int statsType) {
final long totalRunningTimeMs = stats.getGlobalWifiRunningTime(rawRealtimeUs, statsType)
/ 1000;
final double powerDrain = ((totalRunningTimeMs - mTotalAppWifiRunningTimeMs) * mWifiPowerOn)
/ (1000*60*60);
app.wifiRunningTimeMs = totalRunningTimeMs;
app.wifiPowerMah = Math.max(0, powerDrain);
}
@Override
public void reset() {
mTotalAppWifiRunningTimeMs = 0;
}
}