前言
SystemServer 是 Android 系统的核心进程，由 Zygote 孵化，负责启动和管理所有核心系统服务，像是常见的ActivityManagerService、WindowManagerService、PackageManagerService、PowerManagerService等服务，都是在SystemServer的main方法中能够初始化的，这些服务都是运行在system_server进程的线程中。它是 Android 框架层的“大脑”，直接决定了系统的功能性和稳定性。
Zygote进程进入system_server进程
我们在Android 12系统源码_系统启动（二）Zygote进程中有讲过 ZygoteInit的main方法，在解析到 start-system-server 参数后会调用 forkSystemServer方法。
public class ZygoteInit {
public static void main(String[] argv) {
...代码省略...
if (startSystemServer) {
//注释1，fork出system_server子进程
Runnable r = forkSystemServer(abiList, zygoteSocketName, zygoteServer);
//如果是父进程则返回null，如果是system_server子进程则返回SystemServerRunnable
if (r != null) {
r.run();//注释2，在子进程（system_server）中执行，SystemServerRunnable的run方法会进入了SystemServer的main方法
return;
}
}
...代码省略...
}
private static Runnable forkSystemServer(String abiList, String socketName,ZygoteServer zygoteServer) {
...代码省略...
/* Hardcoded command line to start the system server */
String[] args = {
"--setuid=1000",//用户id
"--setgid=1000",//组id
"--setgroups=1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,1021,1023,"
+ "1024,1032,1065,3001,3002,3003,3006,3007,3009,3010,3011,3012",
"--capabilities=" + capabilities + "," + capabilities,
"--nice-name=system_server",
"--runtime-args",
"--target-sdk-version=" + VMRuntime.SDK_VERSION_CUR_DEVELOPMENT,
"com.android.server.SystemServer",//SystemServer类名，只有这个条目是非--开头的
};
if (pid == 0) {
...代码省略...
//由于zygoteServer只有Zygote会使用，子进程system_server不需要使用，于是会将其关闭。
zygoteServer.closeServerSocket();
//继续调用handleSystemServerProcess方法
return handleSystemServerProcess(parsedArgs);
}
return null;
}
private static Runnable handleSystemServerProcess(ZygoteArguments parsedArgs) {
...代码省略...
//调用ZygoteInit的zygoteInit方法
return ZygoteInit.zygoteInit(parsedArgs.mTargetSdkVersion,
parsedArgs.mDisabledCompatChanges,
parsedArgs.mRemainingArgs, cl);
}
public static Runnable zygoteInit(int targetSdkVersion, long[] disabledCompatChanges,
String[] argv, ClassLoader classLoader) {
...代码省略...
//调用RuntimeInit的applicationInit方法
return RuntimeInit.applicationInit(targetSdkVersion, disabledCompatChanges, argv,
classLoader);
}
}
>frameworks/base/core/java/com/android/internal/os/RuntimeInit.java
public class RuntimeInit {
protected static Runnable applicationInit(int targetSdkVersion, long[] disabledCompatChanges,
String[] argv, ClassLoader classLoader) {
...代码省略...
final Arguments args = new Arguments(argv);//解析参数argv
return findStaticMain(args.startClass, args.startArgs, classLoader);
}
static class Arguments {
String startClass;//类路径
String[] startArgs;//参数
Arguments(String args[]) throws IllegalArgumentException {
parseArgs(args);
}
private void parseArgs(String args[])
throws IllegalArgumentException {
int curArg = 0;
for (; curArg < args.length; curArg++) {
String arg = args[curArg];
if (arg.equals("--")) {
curArg++;
break;
} else if (!arg.startsWith("--")) {//com.android.server.SystemServer字符串
break;
}
}
if (curArg == args.length) {
throw new IllegalArgumentException("Missing classname argument to RuntimeInit!");
}
startClass = args[curArg++];
startArgs = new String[args.length - curArg];
System.arraycopy(args, curArg, startArgs, 0, startArgs.length);
}
}
protected static Runnable findStaticMain(String className, String[] argv, ClassLoader classLoader) {
Class<?> cl;
...代码省略..
//获取到SystemServer的类类型
cl = Class.forName(className, true, classLoader);
...代码省略..
Method m;
//获取到main方法的方法id
m = cl.getMethod("main", new Class[] { String[].class });
...代码省略..
//这个就是ZygoteInit类中forkSystemServer的返回值r
return new MethodAndArgsCaller(m, argv);
}
static class MethodAndArgsCaller implements Runnable {
private final Method mMethod;
private final String[] mArgs;
public MethodAndArgsCaller(Method method, String[] args) {
mMethod = method;
mArgs = args;
}
public void run() {
...代码省略...
//通过反射调用mMethod静态方法，这里触发的其实就是SystemServer的main方法
mMethod.invoke(null, new Object[] { mArgs });
...代码省略...
}
}
Zygote进程对应的ZygoteInit的main方法会调用forkSystemServer方法fork出system_server这个子进程，该方法会解析args参数，最终返回MethodAndArgsCaller对象，并进入system_server进程，然后在system_server进程中调用MethodAndArgsCaller的run方法，最终会进入SystemServer的main方法。
SystemServer的main方法
frameworks/base/services/java/com/android/server/SystemServer.java
public final class SystemServer implements Dumpable {
public static void main(String[] args) {
new SystemServer().run();
}
private void run() {
TimingsTraceAndSlog t = new TimingsTraceAndSlog();
...代码省略...
t.traceBegin("InitBeforeStartServices"); //日志打印：SystemServerTiming: startBootstrapServices
//SystemProperties相关属性设置...
...代码省略...
//Here we go! 关键日志打印
Slog.i(TAG, "Entered the Android system server!");
...代码省略...
//创建Looper对象
Looper.prepareMainLooper();
...代码省略...
//加载动态链接库
System.loadLibrary("android_servers");
...代码省略...
//创建一个systemContext，和普通应用的Context一样，system也需要通过Context来获取一些进程的信息环境
createSystemContext();//
...代码省略...
t.traceEnd(); //日志打印：startBootstrapServices took to complete: 1588ms
...代码省略...
// Start services.
try {
t.traceBegin("StartServices");//日志打印：SystemServerTiming: StartServices
//启动引导服务
startBootstrapServices(t);
//启动核心服务
startCoreServices(t);
//启动其他服务
startOtherServices(t);
} catch (Throwable ex) {
Slog.e("System", "******************************************");
Slog.e("System", "************ Failure starting system services", ex);
throw ex;
} finally {
t.traceEnd(); //日志打印：StartServices took to complete: 3997ms
}
...代码省略...
// Loop forever.
Looper.loop();
throw new RuntimeException("Main thread loop unexpectedly exited");
}
}
frameworks/base/services/core/java/com/android/server/utils/TimingsTraceAndSlog.java
public final class TimingsTraceAndSlog extends TimingsTraceLog {
public static final String SYSTEM_SERVER_TIMING_TAG = "SystemServerTiming";
@Override
public void traceBegin(@NonNull String name) {
//打印开始日志，tag为SystemServerTiming，name为开始关键字
Slog.i(mTag, name);
super.traceBegin(name);
}
}
frameworks/base/core/java/android/util/TimingsTraceLog.java
public class TimingsTraceLog {
public void traceBegin(String name) {
...代码省略...
mCurrentLevel++;
mStartNames[mCurrentLevel] = name;
mStartTimes[mCurrentLevel] = SystemClock.elapsedRealtime();
}
public void traceEnd() {
...代码省略...
final String name = mStartNames[mCurrentLevel];
final long duration = SystemClock.elapsedRealtime() - mStartTimes[mCurrentLevel];
mCurrentLevel--;
//打印结束日志信息，tag为SystemServerTiming，name为结束关键字，并记录从开始到结束总共花了多长时间
logDuration(name, duration);
}
public void logDuration(String name, long timeMs) {
Slog.d(mTag, name + " took to complete: " + timeMs + "ms");
}
}
SystemProperties相关属性设置
public final class SystemServer implements Dumpable {
private static final String SYSPROP_START_COUNT = "sys.system_server.start_count";
private static final String SYSPROP_START_ELAPSED = "sys.system_server.start_elapsed";
private static final String SYSPROP_START_UPTIME = "sys.system_server.start_uptime";
private void run() {
...代码省略...
//将启动次数、启动时间写入系统属性
SystemProperties.set(SYSPROP_START_COUNT, String.valueOf(mStartCount));
SystemProperties.set(SYSPROP_START_ELAPSED, String.valueOf(mRuntimeStartElapsedTime));
SystemProperties.set(SYSPROP_START_UPTIME, String.valueOf(mRuntimeStartUptime));
// 写入系统事件日志（便于调试）
EventLog.writeEvent(EventLogTags.SYSTEM_SERVER_START,
mStartCount, mRuntimeStartUptime, mRuntimeStartElapsedTime);
//设置默认时区
String timezoneProperty = SystemProperties.get("persist.sys.timezone");
if (!isValidTimeZoneId(timezoneProperty)) {
//检查时区配置是否有效，无效则默认设为 GMT（格林尼治标准时间）
Slog.w(TAG, "persist.sys.timezone is not valid (" + timezoneProperty+ "); setting to GMT.");
SystemProperties.set("persist.sys.timezone", "GMT");
}
//处理语言和区域设置
if (!SystemProperties.get("persist.sys.language").isEmpty()) {
final String languageTag = Locale.getDefault().toLanguageTag();
//Android现在统一使用 Locale 类管理区域设置。
SystemProperties.set("persist.sys.locale", languageTag);
//清除以前的旧版语言和国家属性
SystemProperties.set("persist.sys.language", "");
SystemProperties.set("persist.sys.country", "");
SystemProperties.set("persist.sys.localevar", "");
}
...代码省略...
//设置 Dalvik/ART 运行时库
SystemProperties.set("persist.sys.dalvik.vm.lib.2", VMRuntime.getRuntime().vmLibrary());
...代码省略...
}
}
启动引导服务
public final class SystemServer implements Dumpable {
private void startBootstrapServices(@NonNull TimingsTraceAndSlog t) {
t.traceBegin("startBootstrapServices");//日志打印：SystemServerTiming: startBootstrapServices
t.traceBegin("StartWatchdog");//日志打印：SystemServerTiming: StartWatchdog
//看门狗
final Watchdog watchdog = Watchdog.getInstance();
watchdog.start();
t.traceEnd();//日志打印：SystemServerTiming: StartWatchdog took to complete: 7ms
...代码省略...
//开启AMS
t.traceBegin("StartActivityManager");//日志打印：SystemServerTiming: StartActivityManager
//调用SystemServiceManager的startService方法，开启ActivityTaskManagerService服务
ActivityTaskManagerService atm = mSystemServiceManager.startService(
ActivityTaskManagerService.Lifecycle.class).getService();
//调用ActivityManagerService.Lifecycle的startService方法，开启ActivityManagerService服务
mActivityManagerService = ActivityManagerService.Lifecycle.startService(
mSystemServiceManager, atm);
//让ActivityManagerService持有SystemServiceManager的引用
mActivityManagerService.setSystemServiceManager(mSystemServiceManager);
mActivityManagerService.setInstaller(installer);
mWindowManagerGlobalLock = atm.getGlobalLock();
t.traceEnd();//日志打印：StartActivityManager took to complete: 348ms
...代码省略...
t.traceBegin("StartPowerManager");//日志打印：StartPowerManager
//电源管理服务
mPowerManagerService = mSystemServiceManager.startService(PowerManagerService.class);
t.traceEnd();//日志打印：StartPowerManager took to complete: 20ms
t.traceBegin("StartRecoverySystemService");//SystemServerTiming: StartRecoverySystemService
//RecoverySystem服务
mSystemServiceManager.startService(RecoverySystemService.Lifecycle.class);
t.traceEnd();//SystemServerTiming: StartRecoverySystemService took to complete: 1ms
...代码省略...
t.traceBegin("StartLightsService");//SystemServerTiming: StartLightsService
//屏幕亮度服务
mSystemServiceManager.startService(LightsService.class);
t.traceEnd();//SystemServerTiming: StartLightsService took to complete: 3ms
...代码省略...
t.traceBegin("StartDisplayManager");//SystemServerTiming: StartDisplayManager
//屏幕设备管理服务
mDisplayManagerService = mSystemServiceManager.startService(DisplayManagerService.class);
t.traceEnd();//SystemServerTiming: StartDisplayManager took to complete: 15ms
//在初始化PackageManagerService服务之前我们要保证至少有个默认屏幕设备
t.traceBegin("WaitForDisplay");//SystemServerTiming: WaitForDisplay
mSystemServiceManager.startBootPhase(t, SystemService.PHASE_WAIT_FOR_DEFAULT_DISPLAY);
t.traceEnd();SystemServerTiming: WaitForDisplay took to complete: 9ms
...代码省略...
t.traceBegin("StartPackageManagerService");//SystemServerTiming: StartPackageManagerService
try {
Watchdog.getInstance().pauseWatchingCurrentThread("packagemanagermain");
//PackageManagerService服务
mPackageManagerService = PackageManagerService.main(mSystemContext, installer,
domainVerificationService, mFactoryTestMode != FactoryTest.FACTORY_TEST_OFF,
mOnlyCore);
} finally {
Watchdog.getInstance().resumeWatchingCurrentThread("packagemanagermain");
}
SystemServerDexLoadReporter.configureSystemServerDexReporter(mPackageManagerService);
mFirstBoot = mPackageManagerService.isFirstBoot();
mPackageManager = mSystemContext.getPackageManager();
t.traceEnd();//SystemServerTiming: StartPackageManagerService took to complete: 1022ms
...代码省略...
t.traceBegin("StartUserManagerService");//SystemServerTiming: StartUserManagerService
//用户管理服务
mSystemServiceManager.startService(UserManagerService.LifeCycle.class);
t.traceEnd();//SystemServerTiming: StartUserManagerService took to complete: 0ms
...代码省略...
t.traceBegin("SetSystemProcess");//SystemServerTiming: SetSystemProcess
mActivityManagerService.setSystemProcess();
t.traceEnd();//SystemServerTiming: SetSystemProcess took to complete: 5ms
...代码省略...
t.traceBegin("InitWatchdog");//SystemServerTiming: InitWatchdog
watchdog.init(mSystemContext, mActivityManagerService);
t.traceEnd();//SystemServerTiming: InitWatchdog took to complete: 0ms
...代码省略...
t.traceBegin("StartOverlayManagerService");//SystemServerTiming: StartOverlayManagerService
mSystemServiceManager.startService(new OverlayManagerService(mSystemContext));
t.traceEnd();//SystemServerTiming: StartOverlayManagerService took to complete: 77ms
...代码省略...
t.traceBegin("StartSensorService");//SystemServerTiming: StartSensorService
mSystemServiceManager.startService(SensorService.class);
t.traceEnd(); //SystemServerTiming: StartSensorService took to complete: 1ms
t.traceEnd();//SystemServerTiming: startBootstrapServices took to complete: 1588ms
}
}
启动核心服务
public final class SystemServer implements Dumpable {
private void startCoreServices(@NonNull TimingsTraceAndSlog t) {
t.traceBegin("startCoreServices");//SystemServerTiming: startCoreServices
t.traceBegin("StartSystemConfigService");//SystemServerTiming: StartSystemConfigService
mSystemServiceManager.startService(SystemConfigService.class);//系统设置
t.traceEnd();//SystemServerTiming: StartSystemConfigService took to complete: 0ms
t.traceBegin("StartBatteryService");//SystemServerTiming: StartBatteryService
mSystemServiceManager.startService(BatteryService.class);//电池状态监控
t.traceEnd();//SystemServerTiming: StartBatteryService took to complete: 15ms
t.traceBegin("StartUsageService");//SystemServerTiming: StartUsageService
mSystemServiceManager.startService(UsageStatsService.class);//用户状态服务
mActivityManagerService.setUsageStatsManager(
LocalServices.getService(UsageStatsManagerInternal.class));
t.traceEnd();//SystemServerTiming: StartUsageService took to complete: 5ms
if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_WEBVIEW)) {
t.traceBegin("StartWebViewUpdateService");//SystemServerTiming: StartWebViewUpdateService
mWebViewUpdateService = mSystemServiceManager.startService(WebViewUpdateService.class);
t.traceEnd();//SystemServerTiming: StartWebViewUpdateService took to complete: 1ms
}
t.traceBegin("StartCachedDeviceStateService");//SystemServerTiming: StartCachedDeviceStateService
mSystemServiceManager.startService(CachedDeviceStateService.class);
t.traceEnd();//SystemServerTiming: StartCachedDeviceStateService took to complete: 0ms
// Tracks cpu time spent in binder calls
t.traceBegin("StartBinderCallsStatsService");//SystemServerTiming: StartBinderCallsStatsService
mSystemServiceManager.startService(BinderCallsStatsService.LifeCycle.class);
t.traceEnd();//SystemServerTiming: StartBinderCallsStatsService took to complete: 0ms
// Tracks time spent in handling messages in handlers.
t.traceBegin("StartLooperStatsService");//SystemServerTiming: StartLooperStatsService
mSystemServiceManager.startService(LooperStatsService.Lifecycle.class);
t.traceEnd();//SystemServerTiming: StartLooperStatsService took to complete: 1ms
// Manages apk rollbacks.
t.traceBegin("StartRollbackManagerService");//SystemServerTiming: StartRollbackManagerService
mSystemServiceManager.startService(ROLLBACK_MANAGER_SERVICE_CLASS);
t.traceEnd();//SystemServerTiming: StartRollbackManagerService took to complete: 19ms
// Tracks native tombstones.
t.traceBegin("StartNativeTombstoneManagerService");//SystemServerTiming: StartNativeTombstoneManagerService
mSystemServiceManager.startService(NativeTombstoneManagerService.class);
t.traceEnd();//SystemServerTiming: StartNativeTombstoneManagerService took to complete: 4ms
// Service to capture bugreports.
t.traceBegin("StartBugreportManagerService");//SystemServerTiming: StartBugreportManagerService
mSystemServiceManager.startService(BugreportManagerService.class);
t.traceEnd();//SystemServerTiming: StartBugreportManagerService took to complete: 1ms
// Serivce for GPU and GPU driver.
t.traceBegin("GpuService");//SystemServerTiming: GpuService
mSystemServiceManager.startService(GpuService.class);//GPU服务
t.traceEnd();//SystemServerTiming: GpuService took to complete: 0ms
t.traceEnd(); // SystemServerTiming: startCoreServices took to complete: 47ms
}
}
启动其他服务
public final class SystemServer implements Dumpable {
private static final String ACCOUNT_SERVICE_CLASS =
"com.android.server.accounts.AccountManagerService$Lifecycle";
private static final String STORAGE_MANAGER_SERVICE_CLASS =
"com.android.server.StorageManagerService$Lifecycle";
private static final String STORAGE_STATS_SERVICE_CLASS =
"com.android.server.usage.StorageStatsService$Lifecycle";
private static final String USB_SERVICE_CLASS =
"com.android.server.usb.UsbService$Lifecycle";
private void startOtherServices(@NonNull TimingsTraceAndSlog t) {
t.traceBegin("startOtherServices");//SystemServerTiming: startOtherServices
final Context context = mSystemContext;
DynamicSystemService dynamicSystem = null;
IStorageManager storageManager = null;//StorageManagerService，管理存储设备（如 SD 卡挂载）
NetworkManagementService networkManagement = null;//管理网络连接（Wi-Fi、移动数据）
IpSecService ipSecService = null;
VpnManagerService vpnManager = null;//VNP管理服务
VcnManagementService vcnManagement = null;
NetworkStatsService networkStats = null;
NetworkPolicyManagerService networkPolicy = null;
NsdService serviceDiscovery = null;
WindowManagerService wm = null;//管理窗口布局和动画。
SerialService serial = null;
NetworkTimeUpdateService networkTimeUpdater = null;
InputManagerService inputManager = null;//处理触摸、按键等输入事件。
TelephonyRegistry telephonyRegistry = null;
ConsumerIrService consumerIr = null;
MmsServiceBroker mmsService = null;
HardwarePropertiesManagerService hardwarePropertiesService = null;
PacProxyService pacProxyService = null;
...代码省略...
mContentResolver = context.getContentResolver();
// The AccountManager must come before the ContentService
t.traceBegin("StartAccountManagerService");//SystemServerTiming: StartAccountManagerService
//账号管理服务
mSystemServiceManager.startService(ACCOUNT_SERVICE_CLASS);
t.traceEnd();//SystemServerTiming: StartAccountManagerService took to complete: 12ms
...代码省略...
t.traceBegin("StartInputManagerService");//SystemServerTiming: StartInputManagerService
inputManager = new InputManagerService(context);
t.traceEnd();//SystemServerTiming: StartInputManagerService took to complete: 12ms
t.traceBegin("DeviceStateManagerService");//SystemServerTiming: DeviceStateManagerService
mSystemServiceManager.startService(DeviceStateManagerService.class);
t.traceEnd();//SystemServerTiming: DeviceStateManagerService took to complete: 3ms
if (!disableCameraService) {
t.traceBegin("StartCameraServiceProxy");//SystemServerTiming: StartCameraServiceProxy
mSystemServiceManager.startService(CameraServiceProxy.class);
t.traceEnd();//SystemServerTiming: StartCameraServiceProxy took to complete: 6ms
}
t.traceBegin("StartWindowManagerService");//SystemServerTiming: StartWindowManagerService
// WMS needs sensor service ready
mSystemServiceManager.startBootPhase(t, SystemService.PHASE_WAIT_FOR_SENSOR_SERVICE);
wm = WindowManagerService.main(context, inputManager, !mFirstBoot, mOnlyCore,
new PhoneWindowManager(), mActivityManagerService.mActivityTaskManager);
ServiceManager.addService(Context.WINDOW_SERVICE, wm, /* allowIsolated= */ false,
DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PROTO);
ServiceManager.addService(Context.INPUT_SERVICE, inputManager,
/* allowIsolated= */ false, DUMP_FLAG_PRIORITY_CRITICAL);
t.traceEnd();//SystemServerTiming: StartWindowManagerService took to complete: 73ms
t.traceBegin("SetWindowManagerService");//SystemServerTiming: SetWindowManagerService
//创建屏幕设备对象
mActivityManagerService.setWindowManager(wm);
t.traceEnd();//SystemServerTiming: SetWindowManagerService took to complete: 72ms
t.traceBegin("WindowManagerServiceOnInitReady");//SystemServerTiming: WindowManagerServiceOnInitReady
wm.onInitReady();
t.traceEnd();//SystemServerTiming: WindowManagerServiceOnInitReady took to complete: 13ms
...代码省略...
t.traceBegin("StartInputManager");//SystemServerTiming: StartInputManager
inputManager.setWindowManagerCallbacks(wm.getInputManagerCallback());
inputManager.start();
t.traceEnd();//SystemServerTiming: StartInputManager took to complete: 19ms
t.traceBegin("DisplayManagerWindowManagerAndInputReady");//SystemServerTiming: DisplayManagerWindowManagerAndInputReady
mDisplayManagerService.windowManagerAndInputReady();
t.traceEnd();//SystemServerTiming: DisplayManagerWindowManagerAndInputReady took to complete: 0ms
if (mFactoryTestMode == FactoryTest.FACTORY_TEST_LOW_LEVEL) {
Slog.i(TAG, "No Bluetooth Service (factory test)");
} else if (!context.getPackageManager().hasSystemFeature
(PackageManager.FEATURE_BLUETOOTH)) {
Slog.i(TAG, "No Bluetooth Service (Bluetooth Hardware Not Present)");
} else {
t.traceBegin("StartBluetoothService");//SystemServerTiming: StartBluetoothService
//蓝牙服务
mSystemServiceManager.startService(BluetoothService.class);
t.traceEnd();//SystemServerTiming: StartBluetoothService took to complete: 2ms
}
...代码省略...
t.traceBegin("MakeDisplayReady");//SystemServerTiming: MakeDisplayReady
try {
wm.displayReady();
} catch (Throwable e) {
reportWtf("making display ready", e);
}
t.traceEnd(); //SystemServerTiming: MakeDisplayReady took to complete: 17ms
if (mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL) {
if (!"0".equals(SystemProperties.get("system_init.startmountservice"))) {
t.traceBegin("StartStorageManagerService");//SystemServerTiming: StartStorageManagerService
try {
/*
* NotificationManagerService is dependant on StorageManagerService,
* (for media / usb notifications) so we must start StorageManagerService first.
*/
mSystemServiceManager.startService(STORAGE_MANAGER_SERVICE_CLASS);
storageManager = IStorageManager.Stub.asInterface(
ServiceManager.getService("mount"));
} catch (Throwable e) {
reportWtf("starting StorageManagerService", e);
}
t.traceEnd();//SystemServerTiming: StartStorageManagerService took to complete: 19ms
t.traceBegin("StartStorageStatsService");//SystemServerTiming: StartStorageStatsService
try {
mSystemServiceManager.startService(STORAGE_STATS_SERVICE_CLASS);
} catch (Throwable e) {
reportWtf("starting StorageStatsService", e);
}
t.traceEnd();//SystemServerTiming: StartStorageStatsService took to complete: 5ms
}
}
...代码省略...
t.traceBegin("StartUiModeManager");//SystemServerTiming: StartUiModeManager
//UI Mode 模式管理
mSystemServiceManager.startService(UiModeManagerService.class);
t.traceEnd();//SystemServerTiming: StartUiModeManager took to complete: 2ms
...代码省略...
t.traceBegin("StartStatusBarManagerService");//SystemServerTiming: StartStatusBarManagerService
try {
statusBar = new StatusBarManagerService(context);//系统栏管理服务
ServiceManager.addService(Context.STATUS_BAR_SERVICE, statusBar);
} catch (Throwable e) {
reportWtf("starting StatusBarManagerService", e);
}
t.traceEnd();//SystemServerTiming: StartStatusBarManagerService took to complete: 0ms
...代码省略...
t.traceBegin("StartNetworkManagementService");//SystemServerTiming: StartNetworkManagementService
try {
networkManagement = NetworkManagementService.create(context);
ServiceManager.addService(Context.NETWORKMANAGEMENT_SERVICE, networkManagement);
} catch (Throwable e) {
reportWtf("starting NetworkManagement Service", e);
}
t.traceEnd();//SystemServerTiming: StartNetworkManagementService took to complete: 4ms
...代码省略...
t.traceBegin("StartFontManagerService");//SystemServerTiming: StartFontManagerService
//字体服务
mSystemServiceManager.startService(new FontManagerService.Lifecycle(context, safeMode));
t.traceEnd();//SystemServerTiming: StartFontManagerService took to complete: 111ms
...代码省略...
t.traceBegin("StartNetworkPolicyManagerService");//SystemServerTiming: StartNetworkManagementService
try {
networkPolicy = new NetworkPolicyManagerService(context, mActivityManagerService,
networkManagement);
ServiceManager.addService(Context.NETWORK_POLICY_SERVICE, networkPolicy);
} catch (Throwable e) {
reportWtf("starting NetworkPolicy Service", e);
}
t.traceEnd();//SystemServerTiming: StartNetworkManagementService took to complete: 4ms
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_WIFI)) {
// Wifi Service must be started first for wifi-related services.
t.traceBegin("StartWifi");//SystemServerTiming: StartWifi
//WIFI服务
mSystemServiceManager.startServiceFromJar(
WIFI_SERVICE_CLASS, WIFI_APEX_SERVICE_JAR_PATH);
t.traceEnd();//SystemServerTiming: StartWifi took to complete: 163ms
t.traceBegin("StartWifiScanning");//SystemServerTiming: StartWifiScanning
//WIFI扫描服务
mSystemServiceManager.startServiceFromJar(
WIFI_SCANNING_SERVICE_CLASS, WIFI_APEX_SERVICE_JAR_PATH);
t.traceEnd();//SystemServerTiming: StartWifiScanning took to complete: 13ms
}
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_WIFI_RTT)) {
t.traceBegin("StartRttService");//SystemServerTiming: StartRttService
//RTT服务
mSystemServiceManager.startServiceFromJar(
WIFI_RTT_SERVICE_CLASS, WIFI_APEX_SERVICE_JAR_PATH);
t.traceEnd();//SystemServerTiming: StartRttService took to complete: 1ms
}
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_WIFI_DIRECT)) {
t.traceBegin("StartWifiP2P");//SystemServerTiming: StartWifiP2P
//P2P服务
mSystemServiceManager.startServiceFromJar(
WIFI_P2P_SERVICE_CLASS, WIFI_APEX_SERVICE_JAR_PATH);
t.traceEnd();//SystemServerTiming: StartWifiP2P took to complete: 8ms
}
...代码省略...
t.traceBegin("StartVpnManagerService");//SystemServerTiming: StartVpnManagerService
try {
vpnManager = VpnManagerService.create(context);
ServiceManager.addService(Context.VPN_MANAGEMENT_SERVICE, vpnManager);
} catch (Throwable e) {
reportWtf("starting VPN Manager Service", e);
}
t.traceEnd();//SystemServerTiming: StartVpnManagerService took to complete: 3ms
...代码省略...
t.traceBegin("StartSystemUpdateManagerService");//SystemServerTiming: StartSystemUpdateManagerService
try {
ServiceManager.addService(Context.SYSTEM_UPDATE_SERVICE,
new SystemUpdateManagerService(context));
} catch (Throwable e) {
reportWtf("starting SystemUpdateManagerService", e);
}
t.traceEnd();//SystemServerTiming: StartSystemUpdateManagerService took to complete: 1ms
...代码省略...
t.traceBegin("StartNotificationManager");//SystemServerTiming: StartNotificationManager
mSystemServiceManager.startService(NotificationManagerService.class);
SystemNotificationChannels.removeDeprecated(context);
SystemNotificationChannels.createAll(context);
notification = INotificationManager.Stub.asInterface(
ServiceManager.getService(Context.NOTIFICATION_SERVICE));
t.traceEnd();//SystemServerTiming: StartNotificationManager took to complete: 30ms
t.traceBegin("StartDeviceMonitor");//SystemServerTiming: StartDeviceMonitor
mSystemServiceManager.startService(DeviceStorageMonitorService.class);
t.traceEnd();//SystemServerTiming: StartDeviceMonitor took to complete: 8ms
t.traceBegin("StartLocationManagerService");//SystemServerTiming: StartLocationManagerService
mSystemServiceManager.startService(LocationManagerService.Lifecycle.class);
t.traceEnd();//SystemServerTiming: StartLocationManagerService took to complete: 3ms
...代码省略...
if (context.getResources().getBoolean(R.bool.config_enableWallpaperService)) {
t.traceBegin("StartWallpaperManagerService");//SystemServerTiming: StartWallpaperManagerService
mSystemServiceManager.startService(WALLPAPER_SERVICE_CLASS);
t.traceEnd();//SystemServerTiming: StartWallpaperManagerService took to complete: 2ms
} else {
Slog.i(TAG, "Wallpaper service disabled by config");
}
t.traceBegin("StartAudioService");//SystemServerTiming: StartAudioService
if (!isArc) {
mSystemServiceManager.startService(AudioService.Lifecycle.class);
} else {
String className = context.getResources()
.getString(R.string.config_deviceSpecificAudioService);
try {
mSystemServiceManager.startService(className + "$Lifecycle");
} catch (Throwable e) {
reportWtf("starting " + className, e);
}
}
t.traceEnd();//SystemServerTiming: StartAudioService took to complete: 98ms
...代码省略...
t.traceBegin("StartAdbService");//SystemServerTiming: StartAdbService
try {
mSystemServiceManager.startService(ADB_SERVICE_CLASS);//开启ADB调试服务
} catch (Throwable e) {
Slog.e(TAG, "Failure starting AdbService");
}
t.traceEnd();//SystemServerTiming: StartAdbService took to complete: 1ms
if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_USB_HOST)
|| mPackageManager.hasSystemFeature(
PackageManager.FEATURE_USB_ACCESSORY)
|| isEmulator) {
// Manage USB host and device support
t.traceBegin("StartUsbService");//SystemServerTiming: StartUsbService
mSystemServiceManager.startService(USB_SERVICE_CLASS);//开启USB服务
t.traceEnd();//SystemServerTiming: StartUsbService took to complete: 1ms
}
...代码省略...
t.traceBegin("StartClipboardService");//SystemServerTiming: StartClipboardService
//剪切板服务
mSystemServiceManager.startService(ClipboardService.class);
t.traceEnd();//SystemServerTiming: StartClipboardService took to complete: 2ms
t.traceBegin("AppServiceManager");//SystemServerTiming: AppServiceManager
mSystemServiceManager.startService(AppBindingService.Lifecycle.class);
t.traceEnd();//SystemServerTiming: AppServiceManager took to complete: 0ms
t.traceBegin("startTracingServiceProxy");//SystemServerTiming: startTracingServiceProxy
mSystemServiceManager.startService(TracingServiceProxy.class);
t.traceEnd();//SystemServerTiming: startTracingServiceProxy took to complete: 1ms
...代码省略...
t.traceBegin("MakeWindowManagerServiceReady");//SystemServerTiming: MakeWindowManagerServiceReady
try {
wm.systemReady();
} catch (Throwable e) {
reportWtf("making Window Manager Service ready", e);
}
t.traceEnd();//SystemServerTiming: MakeWindowManagerServiceReady took to complete: 2ms
...代码省略...
final Configuration config = wm.computeNewConfiguration(DEFAULT_DISPLAY);
DisplayMetrics metrics = new DisplayMetrics();
context.getDisplay().getMetrics(metrics);
context.getResources().updateConfiguration(config, metrics);
// The system context's theme may be configuration-dependent.
final Theme systemTheme = context.getTheme();
if (systemTheme.getChangingConfigurations() != 0) {
systemTheme.rebase();
}
t.traceBegin("MakePowerManagerServiceReady");//SystemServerTiming: MakePowerManagerServiceReady
try {
// TODO: use boot phase
mPowerManagerService.systemReady(mActivityManagerService.getAppOpsService());
} catch (Throwable e) {
reportWtf("making Power Manager Service ready", e);
}
t.traceEnd();//SystemServerTiming: MakePowerManagerServiceReady took to complete: 19ms
//调用ActivityManagerService的systemReady方法
mActivityManagerService.systemReady(() -> {
Slog.i(TAG, "Making services ready");
}
t.traceBegin("StartSystemUI");//SystemServerTiming: StartSystemUI
try {
startSystemUi(context, windowManagerF);
} catch (Throwable e) {
reportWtf("starting System UI", e);
}
t.traceEnd();//SystemServerTiming: StartSystemUI took to complete: 10ms
t.traceEnd(); //SystemServerTiming: startOtherServices took to complete: 2362ms
}
}
时序图
