[20191207][Android10]高德地圖導航功耗場景優化

1. 測試現象

1.1 EPRODUCING PROCEDURES:

1.進入高德 Map(data) wifi)，起點爲自己所在位置，搜索一個位置進行導航；
2.等待30秒後開始記錄電流，持續5分鐘；
3.按Power鍵，滅屏待機；
4.手機滅屏15秒後開始記錄電流，持續3分鐘；

1.2 Test numberSummary

設備	高德地圖導航
測試機	461.82 mA
對比機	369.13 mA

2.分析

2.1 拔屏以扣除LCD影響

設備	高德地圖導航
測試機+450nit帶屏幕導航	405.18 mA
對比機+450nit帶屏幕導航	380.11
測試機+拔屏	174.45 mA
對比機+拔屏	131.76 mA

從上述看扣掉 LCD 同樣有功耗差異，即LCD 關係不大

注意：導航場景：一般是帶導航語音，即需要考慮Audio的影響

2.2 設計實驗找出問題差異

以下是我自己設計的實驗方法

1).對比機與測試機的GPS搜星實驗

GPS puls 搜星查看，我apk放到附件中
只開啓GPS+飛行模式
儘量2臺機器相同環境下同時測試
4.放置5分鐘後，apk主界面截圖

GPS plus+工具	搜星情況
對比機無GPS信號增強器	觀察衛星數量和信號強度
對比機有GPS信號增強器	觀察衛星數量和信號強度
測試機無GPS信號增強器	觀察衛星數量和信號強度
測試機有GPS信號增強器	觀察衛星數量和信號強度

實驗發現：基本無差異，故 GPS 單體應該是沒問題

2).導航電流測試

最暗亮度測試，避免扣掉屏幕帶來的影響
靜音+插入耳機，去除導航語音帶來的影響
儘量2臺機器相同環境下同時測試

測試項目	測試機器(mA)	對比機(mA)
case 1 靜態HOME界面固定牆紙_飛行模式	65.21	68.19
case 2網絡定位條件，高德導航測試：只保持WiFi連接，飛行模式	87.63	88.95
case 3 GPS定位條件，高德導航測試：開啓GPS+插卡+WiFi 連接	147.63	120.71
case 4 GPS定位條件，高德導航測試：GPS增強器+開啓GPS+插卡+WiFi 連接	169.64	153.48

case 1 目的: 對比相同亮度下是否存在差異
case 2 目的: 查看是否網絡定位有問題
case 3 目的：查看是否GPS定位存問題
case 3 目的: 查殺是否與GPS信號強度有關，因爲室內是GPS信號比較弱

上述：

case 1 說明測試機和對比機亮屏下相同亮度的測試電流是基本一致，即基礎的系統功耗是相同的
case 2 說明網絡定位是OK的，說明相同APK在不同機器測試，運行是後臺也基本保持一致,且說明如果GPS不開啓則是導航是好的；
case 3、case 4 說明GPS開啓，會帶來導航功耗影響

3).GPS單體功耗

這塊數據沒有，故需要讓硬件提供：

測試步驟：

Wi-Fi Off, GPS ON, BT OFF, NFC OFF, Fly mode ON.
滅屏，等待1min，記錄平均電流，即是打開GPS時的電流。
在上述的條件時，記錄下可以穩定復現的最小電流值，即是 GPS floor current.
Average current when GPS navigation working：
  	 Step1:通過下拉菜單，打開飛行模式，打開位置服務；
Step2:進入工程模式 adb shell am start -n com.mediatek.ygps/com.mediatek.ygps.YgpsActivity；
Step3:進入Location->YGPS->Enable in BG.(need restart)，重啓後再次進入該界面;
Step4:關閉屏幕，待電流穩定，測試3分鐘，記錄電流A1；
Step5:通過下拉菜單，關閉位置服務；
Step6:進入工程模式，進入Location->YGPS，再回到YGPS界面；
Step7:關閉屏幕，待電流穩定，測試3分鐘，記錄電流A2；
GPS ON=A1-A2

由於不知道 ygps 源碼，通過測試步驟基本猜到，主要是測試GPS開啓電流和工作電流，相當於高德地圖的定位場景，非導航場景

測試數據：

設備	平均電流
測試機	34mA
對比機	34mA

從上面數據看，GPS的工作電流是基本一致的，即GPS單體是OK的

這就奇怪了，GPS單體是好的，爲什麼導航一開GPS就存問題呢？還需要再排除干擾。例如以下干擾：

WiFi 環境因素
4G 插卡因素
應用啓動後會進行頁面、地圖數據、配置文件下載
測試過程中，如果網絡發生變化，熱點不穩定

4).離線導航

Wi-Fi Off, GPS ON, BT OFF, NFC OFF, Fly mode ON，排除WiFi帶來的干擾
最小亮度
使用 what_temp apk抓CPU數據
靜音插耳機
使用高德離線地圖導航

設備	測試機	對比機
高德地圖定位界面	55.13mA	50.13mA
高德地圖導航界面	83.00mA	60.49mA

上述查看：

現象復現，即排除了Wi-Fi Off, GPS ON, BT OFF, NFC OFF, Fly mode影響，即wifi、4G都沒問題
定位場景差異不大，導航場景差異比較大。
需要查看高德地圖定位細節

2.3 高德地圖的dump信息

dumpsys location|grep -B 2 “com.autonavi.minimap”

Tokyo_Lite:/ $ dumpsys location|grep -B 2 "com.autonavi.minimap"
  Battery Saver Location Mode: NO_CHANGE
  Location Listeners:
    Reciever[35eed63 listener UpdateRecord[passive com.autonavi.minimap(10167 foreground) Request[POWER_NONE passive fastest=0] null], isNeedBgGpsRestrict false monitoring location: true]
    Reciever[fe54b41 listener UpdateRecord[passive android(1000 foreground) Request[POWER_NONE passive fastest=+30m0s0ms] null], isNeedBgGpsRestrict false monitoring location: true]
    Reciever[a523146 listener UpdateRecord[passive com.autonavi.minimap(10167 foreground) Request[POWER_NONE passive fastest=+1s0ms] null], isNeedBgGpsRestrict false monitoring location: true]
    Reciever[4698940 listener UpdateRecord[passive android(1000 foreground) Request[POWER_NONE passive fastest=0] null], isNeedBgGpsRestrict false monitoring location: false]
    Reciever[3e939ea listener monitoring location: false]
    Reciever[a629ca9 listener UpdateRecord[gps com.autonavi.minimap(10167 foreground) Request[ACCURACY_FINE gps requested=+1s0ms fastest=+1s0ms] null], isNeedBgGpsRestrict false monitoring location: true]
  Active Records by Provider:
    gps:
      UpdateRecord[gps com.autonavi.minimap(10167 foreground) Request[ACCURACY_FINE gps requested=+1s0ms fastest=+1s0ms] null], isNeedBgGpsRestrict false
--
      UpdateRecord[passive android(1000 foreground) Request[POWER_NONE passive fastest=0] null], isNeedBgGpsRestrict false
      UpdateRecord[passive android(1000 foreground) Request[POWER_NONE passive fastest=+30m0s0ms] null], isNeedBgGpsRestrict false
      UpdateRecord[passive com.autonavi.minimap(10167 foreground) Request[POWER_NONE passive fastest=0] null], isNeedBgGpsRestrict false
      UpdateRecord[passive com.autonavi.minimap(10167 foreground) Request[POWER_NONE passive fastest=+1s0ms] null], isNeedBgGpsRestrict false
--
  Active GnssNavigationMessage Listeners:
  Active GnssStatus Listeners:
    5600 10167 com.autonavi.minimap: false
    5600 10167 com.autonavi.minimap: false
    5600 10167 com.autonavi.minimap: false
    5766 10167 com.autonavi.minimap: false
  Historical Records by Provider:
    android: passive: Min interval 0 seconds: Max interval 1800 seconds: Duration requested 99 total, 99 foreground, out of the last 99 minutes: Currently active
    com.autonavi.minimap: passive: Min interval 0 seconds: Max interval 1 seconds: Duration requested 2 total, 2 foreground, out of the last 98 minutes: Currently active
    com.autonavi.minimap: gps: Interval 1 seconds: Duration requested 2 total, 2 foreground, out of the last 98 minutes: Currently active

查看高德地圖的dump信息，我們基本知道高德地圖申請了哪些定位：

GPS 定位，定位間隔1秒一個
Reciever[a629ca9 listener UpdateRecord[gps com.autonavi.minimap(10167 foreground) Request[ACCURACY_FINE gps requested=+1s0ms fastest=+1s0ms] null], isNeedBgGpsRestrict false monitoring location: true]
passive 定位
Reciever[a523146 listener UpdateRecord[passive com.autonavi.minimap(10167 foreground) Request[POWER_NONE passive fastest=+1s0ms] null], isNeedBgGpsRestrict false monitoring location: true]
監聽了 GnssStatus 數據
Active GnssStatus Listeners:
5600 10167 com.autonavi.minimap: false
5600 10167 com.autonavi.minimap: false
5600 10167 com.autonavi.minimap: false
5766 10167 com.autonavi.minimap: false

2.4 分析高德地圖定位和導航調用的函數

我們在dump locaiton已經知道高德地圖會申請使用GPS，並且定位間隔爲1秒，故不需要在

1) LocationManager 埋點

public class LocationManager {

    public boolean addNmeaListener(
        @NonNull OnNmeaMessageListener listener, @Nullable Handler handler) {
    boolean result;

    // huazhi.su
    if("true".equals(SystemProperties.get("persist.sys.tct.addNmeaListener.debug", "false"))) {
        Log.e(TAG, "skip addNmeaListener");
        return false;
    }
    // huazhi.su
    
    @RequiresPermission(ACCESS_FINE_LOCATION)
    public boolean registerGnssStatusCallback(
            @NonNull GnssStatus.Callback callback, @Nullable Handler handler) {
        boolean result;
        synchronized (mGnssStatusListeners) {
            // huazhi.su
            if("true".equals(SystemProperties.get("persist.sys.tct.registerGnssStatusCallback.debug", "false"))) {
                if("com.autonavi.minimap".equals(mContext.getPackageName())) {
                    Log.e(TAG, "skip registerGnssStatusCallback  packageName:" + mContext.getPackageName());
                }
                return false;
            }
            // huazhi.su

2) 查看導航場景高德地圖使用的sdk情況

場景	API接口
定位場景	requestLocationUpdates、registerGnssStatusCallback
導航場景	requestLocationUpdates、registerGnssStatusCallback、addNmeaListener

即導航場景比定位場景多了 addNmeaListener

12-06 14:10:44.728  3716  3716 W System.err:    at android.location.LocationManager.addNmeaListener(LocationManager.java:2046)
12-06 14:10:44.736  3716  4034 W System.err:    at android.location.LocationManager.registerGnssStatusCallback(LocationManager.java:1944)

    locationManager.registerGnssStatusCallback(new GnssStatus.Callback() {
        @Override
        public void onSatelliteStatusChanged(GnssStatus status) {
            super.onSatelliteStatusChanged(status);
            Log.d(TAG, "onSatelliteStatusChanged");
        }
    });

    locationManager.addNmeaListener(new OnNmeaMessageListener() {
        @Override
        public void onNmeaMessage(String message, long timestamp) {
            Log.d(TAG, "onNmeaMessage message :" + message + ", timestamp :" + timestamp);
            sendRequestWithHttpClient();
        }
    });
    
    locationManager.requestLocationUpdates(GPS_PROVIDER, 1000, 0, mMyLocationListener);

之前的測試GPS單體的功耗基本是 requestLocationUpdates 這個接口的功能，故基本問題不大
且導航和定位場景中，導航場景存在和定位場景不同，故我們可以單獨屏蔽掉 registerGnssStatusCallback、addNmeaListener

3. 問題根源研究

3.1 禁止監聽 GnssStatus 和 Nmea

測試項	平均電流	備註
離線導航	133	異常電流波形
離線導航+禁止監聽 GnssStatus	120	異常電流波形
離線導航+禁止監聽 Nmea	110	異常電流波形
離線導航+禁止監聽 Nmea + GnssStatus	100	正常電流波形

首先我們看下異常電流：特徵是一秒鐘一個波峯，且單個異常波形平均電流就有166mA，基本功耗不被拉大才怪

上述說明：監聽 Nmea + GnssStatus 會帶來功耗，但是肯定要給第三方應用正常使用這個數據

3.1 攔截 GnssStatus 和 Nmea

攔截位置

package com.android.server.location;

public class GnssLocationProvider ...{

    @NativeEntryPoint // libgnss.so上報
    private void reportNmea(long timestamp) {
        // 新增攔截
        ...
        // 對應上層的：public void onNmeaMessage(String message, long timestamp) 方法
        ...
    }
    
    @NativeEntryPoint // libgnss.so上報
    private void reportSvStatus(int svCount, int[] svidWithFlags, float[] cn0s,
        // 新增攔截
        ...
        // 對應上層的：public void onSatelliteStatusChanged(GnssStatus status) { 方法
        ...
    }

}

測試項	平均電流	備註
離線導航	133	異常電流波形
離線導航+攔截 GnssStatus 數據上報	123	異常電流波形
離線導航+攔截 Nmea 數據上報	110	異常電流波形
離線導航+攔截 Nmea + GnssStatus 數據上報	100	正常電流波形

攔截測試也說明 Nmea + GnssStatus 有影響，難道高德地圖會收到數據做一些耗電操作，還是對比機有優化呢？
由於高德地圖、對比機沒有源碼，所以我們無法知道，從源碼一個函數一個函數地分析。看是否源代碼有問題，即瞭解GPS的Nmea + GnssStatus上報給上層的源碼

4. 源碼分析並新增日誌

4.1 源碼數據通路新增日誌

例如 Nmea 數據如何上報給上層apk，在這個數據傳遞的通路新增日誌，每個函數調用的地方都加

1.數據源頭-------------------------------------------------
package com.android.server.location;

    @NativeEntryPoint
    private void reportNmea(long timestamp) {
        if (!mItarSpeedLimitExceeded) {
            int length = native_read_nmea(mNmeaBuffer, mNmeaBuffer.length);
            String nmea = new String(mNmeaBuffer, 0 /* offset */, length);
            mGnssStatusListenerHelper.onNmeaReceived(timestamp, nmea);
        }
    }

2.-------------------------------------------------
public abstract class GnssStatusListenerHelper extends RemoteListenerHelper<IGnssStatusListener> {
        public void onNmeaReceived(final long timestamp, final String nmea) {
        // 遍歷 addNmeaListener 監聽數量，例如高德地圖使用了2個，一個定位註冊的，一個導航場景註冊的
        foreach((IGnssStatusListener listener, CallerIdentity callerIdentity) -> {
            // 檢查是否與定位權限
            if (hasPermission(mContext, callerIdentity)) {
                logPermissionDisabledEventNotReported(TAG, callerIdentity.mPackageName, "NMEA");
                return;
            }
            // 消息傳遞到上層
            listener.onNmeaReceived(timestamp, nmea);
        });
    }
}
3.-------------------------------------------------
public class LocationManager {

    @Override
    public void onNmeaReceived(long timestamp, String nmea) {
        ...
        mGnssHandler.obtainMessage(NMEA_RECEIVED).sendToTarget();
        ...
    }
    
    for (Nmea nmea : mNmeaBuffer) {
        // 數據給上層
        mGnssNmeaListener.onNmeaMessage(nmea.mNmea, nmea.mTimestamp);
    }

4.2 現象發現

1）日誌大量打印，這裏1秒鐘70組數據從底層上報出來，都需要經過上述的函數，簡直是太頻繁

01-01 00:04:54.516  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GNGGA,160454.011,8960.0000,N,00000.0000,E,0,0,,137.0,M,13.0,M,,*5F
01-01 00:04:54.516  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GNGGA,160454.011,8960.0000,N,00000.0000,E,0,0,,137.0,M,13.0,M,,*5F
01-01 00:04:54.518  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GNGGA,160454.011,8960.0000,N,00000.0000,E,0,0,,137.0,M,13.0,M,,*5F
01-01 00:04:54.519  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30
01-01 00:04:54.520  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30
01-01 00:04:54.522  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30
01-01 00:04:54.522  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30
01-01 00:04:54.522  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GLGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*2C
01-01 00:04:54.524  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GLGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*2C
01-01 00:04:54.524  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GLGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*2C
01-01 00:04:54.526  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GLGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*2C
01-01 00:04:54.526  3740  4447 E LocationManager: skip onNmeaReceived: nmea$BDGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*21
01-01 00:04:54.527  3328  4051 E LocationManager: skip onNmeaReceived: nmea$BDGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*21
01-01 00:04:54.527  3328  4051 E LocationManager: skip onNmeaReceived: nmea$BDGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*21
01-01 00:04:54.527  3328  4561 E LocationManager: skip onNmeaReceived: nmea$BDGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*21
01-01 00:04:54.528  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GAGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*21
01-01 00:04:54.529  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GAGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*21
01-01 00:04:54.529  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GAGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*21
01-01 00:04:54.529  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GAGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*21
01-01 00:04:54.531  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GPGSV,1,1,0*49
01-01 00:04:54.531  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GPGSV,1,1,0*49
01-01 00:04:54.531  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GPGSV,1,1,0*49
01-01 00:04:54.533  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GLGSV,1,1,0*55
01-01 00:04:54.533  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GLGSV,1,1,0*55
01-01 00:04:54.534  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GPGSV,1,1,0*49
01-01 00:04:54.534  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GLGSV,1,1,0*55
01-01 00:04:54.535  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GLGSV,1,1,0*55
01-01 00:04:54.535  3740  4447 E LocationManager: skip onNmeaReceived: nmea$BDGSV,1,1,0*58
01-01 00:04:54.536  3328  4051 E LocationManager: skip onNmeaReceived: nmea$BDGSV,1,1,0*58
01-01 00:04:54.536  3328  4561 E LocationManager: skip onNmeaReceived: nmea$BDGSV,1,1,0*58
01-01 00:04:54.536  3328  4561 E LocationManager: skip onNmeaReceived: nmea$BDGSV,1,1,0*58
01-01 00:04:54.537  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GAGSV,1,1,0*58
01-01 00:04:54.537  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GAGSV,1,1,0*58
01-01 00:04:54.538  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GAGSV,1,1,0*58
01-01 00:04:54.538  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GAGSV,1,1,0*58
01-01 00:04:54.539  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GNRMC,160454.011,V,8960.0000,N,00000.0000,E,0.000,0.00,311218,,,N*55
01-01 00:04:54.539  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GNRMC,160454.011,V,8960.0000,N,00000.0000,E,0.000,0.00,311218,,,N*55
01-01 00:04:54.539  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GNRMC,160454.011,V,8960.0000,N,00000.0000,E,0.000,0.00,311218,,,N*55
01-01 00:04:54.540  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GNVTG,0.00,T,,M,0.000,N,0.000,K,N*2C
01-01 00:04:54.541  3328  4561 E LocationManager: skip onNmeaReceived: nmea$GNVTG,0.00,T,,M,0.000,N,0.000,K,N*2C
01-01 00:04:54.542  3328  3345 E LocationManager: skip onNmeaReceived: nmea$GNVTG,0.00,T,,M,0.000,N,0.000,K,N*2C
01-01 00:04:54.542  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GNRMC,160454.011,V,8960.0000,N,00000.0000,E,0.000,0.00,311218,,,N*55
01-01 00:04:54.542  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GNVTG,0.00,T,,M,0.000,N,0.000,K,N*2C
01-01 00:04:54.542  3740  4447 E LocationManager: skip onNmeaReceived: nmea$PMTKTSX1,5012,326233.306,43.336,38.845,59000000,32.622746,32.623331,0.000000,-0.225000,0.000000,32.623*7C
01-01 00:04:54.543  3328  4051 E LocationManager: skip onNmeaReceived: nmea$PMTKTSX1,5012,326233.306,43.336,38.845,59000000,32.622746,32.623331,0.000000,-0.225000,0.000000,32.623*7C
01-01 00:04:54.544  3328  4051 E LocationManager: skip onNmeaReceived: nmea$PMTKTSX1,5012,326233.306,43.336,38.845,59000000,32.622746,32.623331,0.000000,-0.225000,0.000000,32.623*7C
01-01 00:04:54.544  3328  3345 E LocationManager: skip onNmeaReceived: nmea$PMTKTSX1,5012,326233.306,43.336,38.845,59000000,32.622746,32.623331,0.000000,-0.225000,0.000000,32.623*7C
01-01 00:04:54.544  3740  4447 E LocationManager: skip onNmeaReceived: nmea$PMTKGEPH,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*04
01-01 00:04:54.545  3328  3345 E LocationManager: skip onNmeaReceived: nmea$PMTKGEPH,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*04
01-01 00:04:54.545  3328  4051 E LocationManager: skip onNmeaReceived: nmea$PMTKGEPH,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*04
01-01 00:04:54.546  3328  4051 E LocationManager: skip onNmeaReceived: nmea$PMTKGEPH,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*04
01-01 00:04:54.546  3740  4447 E LocationManager: skip onNmeaReceived: nmea$PMTKGALM,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*19
01-01 00:04:54.547  3328  4051 E LocationManager: skip onNmeaReceived: nmea$PMTKGALM,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*19
01-01 00:04:54.547  3328  3345 E LocationManager: skip onNmeaReceived: nmea$PMTKGALM,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*19
01-01 00:04:54.548  3328  4051 E LocationManager: skip onNmeaReceived: nmea$PMTKGALM,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*19
01-01 00:04:54.548  3740  4447 E LocationManager: skip onNmeaReceived: nmea$GNACCURACY,3162.1,180.0,3.5,500.0*29
01-01 00:04:54.548  3328  4051 E LocationManager: skip onNmeaReceived: nmea$GNACCURACY,3162.1,180.0,3.5,500.0*29
01-01 00:04:54.549  3328  3345 E LocationManager: skip onNmeaReceived: nmea$GNACCURACY,3162.1,180.0,3.5,500.0*29
01-01 00:04:54.549  3328  3345 E LocationManager: skip onNmeaReceived: nmea$GNACCURACY,3162.1,180.0,3.5,500.0*29
01-01 00:04:54.550  3740  4447 E LocationManager: skip onNmeaReceived: nmea$PMTKAGC,160454.011,6174,6241,7189,7273,0,0,0*68
01-01 00:04:54.550  3328  3345 E LocationManager: skip onNmeaReceived: nmea$PMTKAGC,160454.011,6174,6241,7189,7273,0,0,0*68
01-01 00:04:54.551  3328  3345 E LocationManager: skip onNmeaReceived: nmea$PMTKAGC,160454.011,6174,6241,7189,7273,0,0,0*68
01-01 00:04:54.551  3328  4051 E LocationManager: skip onNmeaReceived: nmea$PMTKAGC,160454.011,6174,6241,7189,7273,0,0,0*68
01-01 00:04:54.553  3740  4447 E LocationManager: skip onNmeaReceived: nmea$PMTKAG2,160454.011,6*1C
01-01 00:04:54.553  3328  4051 E LocationManager: skip onNmeaReceived: nmea$PMTKAG2,160454.011,6*1C
01-01 00:04:54.553  3328  3345 E LocationManager: skip onNmeaReceived: nmea$PMTKAG2,160454.011,6*1C
01-01 00:04:54.554  3328  3345 E LocationManager: skip onNmeaReceived: nmea$PMTKAG2,160454.011,6*1C

2）異常發現

發現只要去掉 hasPermission 的調用，功耗就能掉下來，沒想到是這個函數搞得鬼

    public void onNmeaReceived(final long timestamp, final String nmea) {

        foreach((IGnssStatusListener listener, CallerIdentity callerIdentity) -> {
            // huazhi.su add start
            if("true".equals(SystemProperties.get("persist.sys.Helper.hasPermission", "false"))) {
                // 實測1秒中被調用了70次，去除後平均電流減少20mA
                // 這個判斷作用:若用戶定位的時候突然關閉GPS權限，則也要相應停止數據上報到上層
                // 出發點是好：但是1秒鐘判斷了70次就不厚道了，且不同應用註冊的數量不同，故這裏的次數也不一樣
                if (!hasPermission(mContext, callerIdentity)) {
                    logPermissionDisabledEventNotReported(TAG, callerIdentity.mPackageName, "NMEA");
                    return;
                }
            }
            // huazhi.su add end
            listener.onNmeaReceived(timestamp, nmea);

        });
        
    protected boolean hasPermission(Context context, CallerIdentity callerIdentity) {
        if (LocationPermissionUtil.doesCallerReportToAppOps(context, callerIdentity)) {
            // The caller is identified as a location provider that will report location
            // access to AppOps. Skip noteOp but do checkOp to check for location permission.
            return mAppOps.checkOpNoThrow(AppOpsManager.OP_FINE_LOCATION, callerIdentity.mUid,
                    callerIdentity.mPackageName) == AppOpsManager.MODE_ALLOWED;
        }

        return mAppOps.noteOpNoThrow(AppOpsManager.OP_FINE_LOCATION, callerIdentity.mUid,
                callerIdentity.mPackageName) == AppOpsManager.MODE_ALLOWED;
    }

上述中 reportSvStatus 也使用到了 hasPermission 的判斷，但是實測回調的次數沒有 reportNmea多，故功耗電流小一些

    public void onSvStatusChanged (
        ...
        hasPermission(mContext, callerIdentity)
        ...
    }

5. 問題發現與解決

5.1. 功耗問題原因

去掉了 hasPermission 就好，說明系統也經不起頻繁執行某個函數的方法

5.2. 分析

源碼也存在問題，爲什麼這麼頻繁調用的地方，每次都是執行一個函數，幹嘛不把這個變量的狀態保持下來。讀狀態比去執行函數的效率高多了。
估計 Google 寫這個函數的時候，沒考慮的這裏實際會被頻繁調用到

5.3. 解決方案

監聽權限變化事件，當權限改變的時候，更新下對應uid的權限，並保存起來

    context.getPackageManager().addOnPermissionsChangeListener(mOnPermissionsChangedListener);

    private OnPermissionsChangedListener mOnPermissionsChangedListener = new OnPermissionsChangedListener() {

        public void onPermissionsChanged(int uid) {
            updatePermissionsChanged(uid);
        }
    };

若當前保存了uid的權限狀態，則讀狀態，而不是每次執行函數獲取，提高效率

    private boolean isHasPermission(Context context, CallerIdentity callerIdentity) {
        if(mPermissionsList.containsKey(callerIdentity.mUid)) {
            return mPermissionsList.get(callerIdentity.mUid);
        } else {
            boolean isHasPermission = hasPermission(mContext, callerIdentity);
            mPermissionsList.put(callerIdentity.mUid, isHasPermission);
            return isHasPermission;
        }
    }

5.4 高德地圖導航場景電流優化了 30mA

優化後電流由 133mA 下降到100mA, 1秒鐘一個的異常波形也消失了。
由於這裏數據是我自己測的