android process information

桃扇骨 2023-10-16 22:43 44阅读 0赞

**Android Process Information**

本文描述了android启动之后的系统进程列表，并从log的角度来初步分析一下zygote进程的启动过程.

**1 Process list:**

用PS可以得到进程列表，现就最主要的一些进程作一个简单的介绍：

USER     PID   PPID  VSIZE RSS   WCHAN    PC         NAME
    
    root     1     0     548   196   c00b8c14 0000d5cc S /init
    
    ......
    
    root     734   1     72000 14172 c00b92b0 afe0c5a4 S zygote
    
    root     769   1     716   264   c02265ec afe0c1dc S /system/bin/logcat
    
    system   825   734   574128 28360 ffffffff afe0c47c S system_server
    
    radio    877   734   158260 20040 ffffffff afe0d404 S com.android.phone
    
    app_18   960   734   104180 15208 ffffffff afe0d404 S com.android.mms
    
    app_8    979   734   118860 14044 ffffffff afe0d404 S android.process.media
    
    app_9    991   734   91980 12264 ffffffff afe0d404 S com.android.alarmclock
    
    app_14   1025  734   95636 13036 ffffffff afe0d404 S com.android.calendar
    
    app_20   1146  734   99260 15320 ffffffff afe0d404 S com.android.music
    
    app_47   1157  734   100204 15964 ffffffff afe0d404 S com.motorola.camera
    
    app_11   1183  734   122672 23576 ffffffff afe0d404 S com.android.browser
    
    app_6    1199  734   117032 20388 ffffffff afe0d404 S oms.mobilemusic
    
    system   1244  734   99292 15940 ffffffff afe0d404 S com.android.settings
    ......

正如linux系统一样，第一个启动的进程当然是init进程了，init的父进程id是0，即kenel。init进程是第一个用户空间进程，它又派生了许多进程，其中就包括Android中的zygote进程。

另外，从以上进程列表可以看出，所有应用层的进程都是zygote 的子进程，事实上，jvm的初始化就是从zygote开始的，zygote是init的子进程，zygote是通过init.rc中启动的。

logcat：用于android log的管理。我们用locat命令的时候，其实最终就是需要这个logcat进程去实现的。

system\_server：父类是zygote，我们通常所说的Android Framwork其实就是和这个system\_server密切对应的。许多系统服务都是运行在这个进程中的。

我们再从以下的启动log 中来理解一下android的启动过程，包括runtime：

**2 log:**

> 09-07 06:21:51.218: INFO/vold(538): Android Volume Daemon version 2.0
> 
> 09-07 06:21:51.227: INFO/DEBUG(539): debuggerd: Jun 30 2009 17:00:51
> 
> 09-07 06:21:51.247: ERROR/vold(538): Error opening switch name path '/sys/class/switch/test2' (No such file or directory)
> 
> 09-07 06:21:51.247: ERROR/vold(538): Error bootstrapping switch '/sys/class/switch/test2' (m)
> 
> 09-07 06:21:51.247: ERROR/vold(538): Error opening switch name path '/sys/class/switch/test' (No such file or directory)
> 
> 09-07 06:21:51.247: ERROR/vold(538): Error bootstrapping switch '/sys/class/switch/test' (m)
> 
> 09-07 06:21:51.247: DEBUG/vold(538): Bootstrapping complete
> 
> 09-07 06:21:51.397: ERROR/flash\_image(544): can't find recovery partition
> 
> 09-07 06:21:51.468: DEBUG/qemud(546): entering main loop
> 
> **09-07 06:21:52.288: DEBUG/AndroidRuntime(541): >>>>>>>>>>>>>> AndroidRuntime START** <<<<<<<<<<<<<<
> 
> 09-07 06:21:52.288: DEBUG/AndroidRuntime(541): CheckJNI is ON
> 
> 09-07 06:21:52.407: DEBUG/qemud(546): fdhandler\_accept\_event: accepting on fd 10
> 
> 09-07 06:21:52.407: DEBUG/qemud(546): created client 0xe078 listening on fd 8
> 
> 09-07 06:21:52.407: DEBUG/qemud(546): fdhandler\_event: disconnect on fd 8
> 
> 09-07 06:21:52.458: DEBUG/qemud(546): fdhandler\_accept\_event: accepting on fd 10
> 
> 09-07 06:21:52.458: DEBUG/qemud(546): created client 0xf028 listening on fd 8
> 
> 09-07 06:21:52.458: DEBUG/qemud(546): client\_fd\_receive: attempting registration for service 'gsm'
> 
> 09-07 06:21:52.458: DEBUG/qemud(546): client\_fd\_receive: -> received channel id 1
> 
> 09-07 06:21:52.468: DEBUG/qemud(546): client\_registration: registration succeeded for client 1
> 
> 09-07 06:21:52.937: INFO/(542): ServiceManager: 0xac38
> 
> 09-07 06:21:52.957: INFO/AudioFlinger(542): AudioFlinger's thread ready to run for output 0
> 
> 09-07 06:21:52.957: INFO/CameraService(542): CameraService started: pid=542
> 
> 09-07 06:21:52.978: DEBUG/AndroidRuntime(541): --- registering native functions ---
> 
> **09-07 06:21:53.308: INFO/Zygote(541): Preloading classes...**
> 
> **09-07 06:21:53.318: DEBUG/dalvikvm(541): GC freed 764 objects / 42216 bytes in 11ms**
> 
> 09-07 06:21:53.517: DEBUG/dalvikvm(541): GC freed 278 objects / 17160 bytes in 4ms
> 
> 09-07 06:21:53.898: DEBUG/dalvikvm(541): GC freed 208 objects / 12696 bytes in 6ms
> 
> 09-07 06:21:53.988: DEBUG/dalvikvm(541): Trying to load lib /system/lib/libmedia\_jni.so 0x0
> 
> 09-07 06:21:54.148: DEBUG/dalvikvm(541): Added shared lib /system/lib/libmedia\_jni.so 0x0
> 
> 09-07 06:21:54.148: DEBUG/dalvikvm(541): Trying to load lib /system/lib/libmedia\_jni.so 0x0
> 
> 09-07 06:21:54.158: DEBUG/dalvikvm(541): Shared lib '/system/lib/libmedia\_jni.so' already loaded in same CL 0x0
> 
> 09-07 06:21:54.158: DEBUG/dalvikvm(541): Trying to load lib /system/lib/libmedia\_jni.so 0x0
> 
> 09-07 06:21:54.158: DEBUG/dalvikvm(541): Shared lib '/system/lib/libmedia\_jni.so' already loaded in same CL 0x0
> 
> 09-07 06:21:54.158: DEBUG/dalvikvm(541): Trying to load lib /system/lib/libmedia\_jni.so 0x0
> 
> 09-07 06:21:54.158: DEBUG/dalvikvm(541): Shared lib '/system/lib/libmedia\_jni.so' already loaded in same CL 0x0
> 
> 09-07 06:21:54.168: DEBUG/dalvikvm(541): GC freed 462 objects / 29144 bytes in 8ms
> 
> ......
> 
> 09-07 06:22:03.509: INFO/dalvikvm(541): Splitting out new zygote heap
> 
> 09-07 06:22:03.569: INFO/dalvikvm(541): System server process 570 has been created
> 
> 09-07 06:22:03.569: INFO/Zygote(541): Accepting command socket connections
> 
> **09-07 06:22:03.638: INFO/jdwp(570): received file descriptor 10 from ADB**
> 
> 09-07 06:22:03.797: DEBUG/dalvikvm(570): Trying to load lib /system/lib/libandroid\_servers.so 0x0
> 
> ......
> 
> 09-07 06:22:04.179: INFO/SystemServer(570): Entered the Android system server!
> 
> **09-07 06:22:04.209: INFO/sysproc(570): System server: entering thread pool.**
> 
> 09-07 06:22:04.267: ERROR/GLLogger(570): couldn't load <libhgl.so> library (Cannot find library)
> 
> 09-07 06:22:04.338: INFO/SystemServer(570): **Starting Power Manager**.
> 
> 09-07 06:22:04.387: INFO/ARMAssembler(570): generated scanline\_\_00000077:03545404\_00000A01\_00000000 \[ 30 ipp\] (51 ins) at \[0x190ed0:0x190f9c\] in 6840752 ns
> 
> **09-07 06:22:04.397: INFO/SystemServer(570): Starting Activity Manager**.
> 
> 09-07 06:22:04.578: INFO/SystemServer(570): Starting telephony registry
> 
> 09-07 06:22:04.588: INFO/SystemServer(570): Starting Package Manager.
> 
> 09-07 06:22:04.619: INFO/Installer(570): connecting...
> 
> 09-07 06:22:04.619: INFO/installd(543): new connection
> 
> 09-07 06:22:04.717: INFO/PackageManager(570): Got library android.awt in /system/framework/android.awt.jar
> 
> 09-07 06:22:04.728: INFO/PackageManager(570): Got library android.test.runner in /system/framework/android.test.runner.jar
> 
> 09-07 06:22:04.728: INFO/PackageManager(570): Got library com.android.im.plugin in /system/framework/com.android.im.plugin.jar
> 
> 09-07 06:22:05.078: DEBUG/PackageManager(570): Scanning app dir /system/framework
> 
> ......
> 
> 07 06:22:07.780: INFO/SystemServer(570): **Starting Window Manager.**
> 
> ......
> 
> 07 06:22:22.187: DEBUG/HomeLoaders(611): --> **starting applications loader**
> 
> ......

从log 中也可以看出：

1. 在zygote启动之后，GC在不停地进行垃圾回收;

2. Framework中的组件都是在SystemServer初始化的，这一点，从android的源码也能看出来;

3. 在启动的时候，load了许多常用的类，包括但不限于libmedia\_jni.so,libandroid\_servers.so...

4. 最后是启动应用层的组件.