轉載-Android EventLog含義

一. 概述

在調試分析Android的過程中，比較常用的地查看EventLog，非常簡潔明瞭地展現當前Activity各種狀態，當然不至於此，比如還有window的信息。那麼本文就列舉以下am相關的tags含義。

本文涉及的源碼類有EventLog.java, EventLogTags.java，另外tags格式的定義位於文件/system/etc/event-log-tags。

如果在終端輸入：

logcat -b events

那麼會輸出大量類似這樣的信息：

06-01 13:44:55.518  7361  8289 I am_create_service: [0,111484394,.StatService,10094,7769]
06-01 13:44:55.540  7361  8343 I am_proc_bound: [0,3976,com.android.providers.calendar]
06-01 13:44:55.599  7361  8033 I am_create_service: [0,61349752,.UpdateService,10034,1351]
06-01 13:44:55.625  7361  7774 I am_destroy_service: [0,61349752,1351]
...

通過字面意思，就能得到不少信息量，比如am_create_service，創建service，但是後面括號中內容的具體含義，其實有很高的價值。 接下來通過一張表格來展示含義。

二. EventLog

2.1 ActivityManager

Num	TagName	格式	功能
30001	am_finish_activity	User,Token,TaskID,ComponentName,Reason
30002	am_task_to_front	User,Task
30003	am_new_intent	User,Token,TaskID,ComponentName,Action,MIMEType,URI,Flags
30004	am_create_task	User ,Task ID
30005	am_create_activity	User ,Token ,TaskID ,ComponentName,Action,MIMEType,URI,Flags
30006	am_restart_activity	User ,Token ,TaskID,ComponentName
30007	am_resume_activity	User ,Token ,TaskID,ComponentName
30008	am_anr	User ,pid ,Package Name,Flags ,reason	ANR
30009	am_activity_launch_time	User ,Token ,ComponentName,time
30010	am_proc_bound	User ,PID ,ProcessName
30011	am_proc_died	User ,PID ,ProcessName
30012	am_failed_to_pause	User ,Token ,Wanting to pause,Currently pausing
30013	am_pause_activity	User ,Token ,ComponentName
30014	am_proc_start	User ,PID ,UID ,ProcessName,Type,Component
30015	am_proc_bad	User ,UID ,ProcessName
30016	am_proc_good	User ,UID ,ProcessName
30017	am_low_memory	NumProcesses	Lru
30018	am_destroy_activity	User ,Token ,TaskID,ComponentName,Reason
30019	am_relaunch_resume_activity	User ,Token ,TaskID,ComponentName
30020	am_relaunch_activity	User ,Token ,TaskID,ComponentName
30021	am_on_paused_called	User ,ComponentName
30022	am_on_resume_called	User ,ComponentName
30023	am_kill	User ,PID ,ProcessName,OomAdj ,Reason	殺進程
30024	am_broadcast_discard_filter	User ,Broadcast ,Action,ReceiverNumber,BroadcastFilter
30025	am_broadcast_discard_app	User ,Broadcast ,Action,ReceiverNumber,App
30030	am_create_service	User ,ServiceRecord ,Name,UID ,PID
30031	am_destroy_service	User ,ServiceRecord ,PID
30032	am_process_crashed_too_much	User ,Name,PID
30033	am_drop_process	PID
30034	am_service_crashed_too_much	User ,Crash Count,ComponentName,PID
30035	am_schedule_service_restart	User ,ComponentName,Time
30036	am_provider_lost_process	User ,Package Name,UID ,Name
30037	am_process_start_timeout	User ,PID ,UID ,ProcessName	timeout
30039	am_crash	User ,PID ,ProcessName,Flags ,Exception,Message,File,Line	Crash
30040	am_wtf	User ,PID ,ProcessName,Flags ,Tag,Message	Wtf
30041	am_switch_user	id
30042	am_activity_fully_drawn_time	User ,Token ,ComponentName,time
30043	am_focused_activity	User ,ComponentName
30044	am_home_stack_moved	User ,To Front ,Top Stack Id ,Focused Stack Id ,Reason
30045	am_pre_boot	User ,Package
30046	am_meminfo	Cached,Free,Zram,Kernel,Native	內存
30047	am_pss	Pid, UID, ProcessName, Pss, Uss	進程

下面列舉tag可能使用的部分場景：

• am_low_memory：位於AMS.killAllBackgroundProcesses或者AMS.appDiedLocked，記錄當前Lru進程隊列長度。
• am_pss：位於AMS.recordPssSampleLocked(
• am_meminfo：位於AMS.dumpApplicationMemoryUsage
• am_proc_start:位於AMS.startProcessLocked，啓動進程
• am_proc_bound:位於AMS.attachApplicationLocked
• am_kill: 位於ProcessRecord.kill，殺掉進程
• am_anr: 位於AMS.appNotResponding
• am_crash:位於AMS.handleApplicationCrashInner
• am_wtf:位於AMS.handleApplicationWtf
• am_activity_launch_time：位於ActivityRecord.reportLaunchTimeLocked()，後面兩個參數分別是thisTime和 totalTime.
• am_activity_fully_drawn_time:位於ActivityRecord.reportFullyDrawnLocked, 後面兩個參數分別是thisTime和 totalTime
• am_broadcast_discard_filter:位於BroadcastQueue.logBroadcastReceiverDiscardLocked
• am_broadcast_discard_app:位於BroadcastQueue.logBroadcastReceiverDiscardLocked

Activity生命週期相關的方法:

• am_on_resume_called: 位於AT.performResumeActivity
• am_on_paused_called: 位於AT.performPauseActivity, performDestroyActivity
• am_resume_activity: 位於AS.resumeTopActivityInnerLocked
• am_pause_activity: 位於AS.startPausingLocked
• am_finish_activity: 位於AS.finishActivityLocked, removeHistoryRecordsForAppLocked
• am_destroy_activity: 位於AS.destroyActivityLocked
• am_focused_activity: 位於AMS.setFocusedActivityLocked, clearFocusedActivity
• am_restart_activity: 位於ASS.realStartActivityLocked
• am_create_activity: 位於ASS.startActivityUncheckedLocked
• am_new_intent: 位於ASS.startActivityUncheckedLocked
• am_task_to_front: 位於AS.moveTaskToFrontLocked

2.2 Power

Num	TagName	格式	功能
2722	battery_level	level, voltage, temperature
2723	battery_status	status,health,present,plugged,technology
2730	battery_discharge	duration, minLevel,maxLevel
2724	power_sleep_requested	wakeLocksCleared	喚醒鎖數量
2725	power_screen_broadcast_send	wakelockCount
2726	power_screen_broadcast_done	on, broadcastDuration, wakelockCount
2727	power_screen_broadcast_stop	which,wakelockCount	系統還沒進入ready狀態
2728	power_screen_state	offOrOn, becauseOfUser, totalTouchDownTime, touchCycles
2729	power_partial_wake_state	releasedorAcquired, tag

部分含義：

• battery_level: [19,3660,352] //剩餘電量19%, 電池電壓3.66v, 電池溫度35.2℃
• power_screen_state: [0,3,0,0] // 滅屏狀態(0), 屏幕超時(3). 當然還有其他設備管理策略(1),其他理由都爲用戶行爲(2)
• power_screen_state: [1,0,0,0] // 亮屏狀態(1)

下面列舉tag可能使用的部分場景：

• power_sleep_requested: 位於PMS.goToSleepNoUpdateLocked
• power_screen_state:位於Notifer.handleEarlyInteractiveChange, handleLateInteractiveChange

三. EventLog完整語義分析

在源碼EventLogTags.java中,有大量類似的定義,那麼括號中數字是什麼含義呢? (以進程啓動爲例)

30014 am_proc_start (User|1|5),(PID|1|5),(UID|1|5),(Process Name|3),(Type|3),(Component|3)

am_proc_start之後緊跟着的幾個括號，其中括號裏的內容格式如下：

(<name>|data type[|data unit])
(<名字>|數據類型[|數據單位])

那麼(User|1|5) ==> 名字爲User, 數據類型爲1，數據單位爲5，下面再來看看數據類型和數據單位：

3.1 數據類型

• 1: int
• 2: long
• 3: string
• 4: list

數據類型中int和string用得最多.

3.2 數據單位

• 1: Number of objects(對象個數)
• 2: Number of bytes(字節數)
• 3: Number of milliseconds(毫秒)
• 4: Number of allocations(分配個數)
• 5: Id
• 6: Percent(百分比)

3.3 實例解析

有了前面的準備知識，再來完整的看看如下語句：

am_proc_start (User|1|5),(PID|1|5),(UID|1|5),(Process Name|3),(Type|3),(Component|3)
am_proc_start: [0,9227,10002,com.android.browser,content provider,com.android.browser/.provider.BrowserProvider2]

含義如下：

進程啓動: UserId=0, pid=9227, uid=10002, ProcessName=com.android.browser, 數據類型=ContentProvider, 組件=com.android.browser/.provider.BrowserProvider2