（两百五十八）以perfetto的视角观察flutter的加载
1.抓取trace使用https://blog.csdn.net/sinat_20059415/article/details/106307905中网页抓取方式抓取trace对应tracehttps://download.csdn.net/download/sinat_20059415/124529432.简要分析测试flutter还是之前写的https://blog.csdn.net/sinat
1.抓取trace
使用https://blog.csdn.net/sinat_20059415/article/details/106307905中网页抓取方式抓取trace
对应trace https://download.csdn.net/download/sinat_20059415/12452943
2.简要分析
测试flutter还是之前写的https://blog.csdn.net/sinat_20059415/article/details/105920254#t4里的app
mCurrentUserId=0
Current looper: Looper (android.ui, tid=1671)
mCurrentUserId=0
mCurrentFocus=Window{40b2a2c u0 com.example.flutterlayouttest/com.example.flutterlayouttest.MainActivity}
mCurrent=[0,96][1080,2340]
Current looper: Looper (android.ui, tid=1671)
mCurrentAppOrientation=SCREEN_ORIENTATION_UNSPECIFIED
mCurrentRotation=ROTATION_0
对应的包名是com.example.flutterlayouttest
2.1 线程
可以看到flutter包含了很多线程，具体用命令看一下
参考https://blog.csdn.net/sinat_20059415/article/details/94127428#t4
ps -AfT
raphael:/ # ps -AfT | grep flutter
u0_a234 27992 27992 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 27998 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28003 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28004 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28005 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28006 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28007 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28008 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28009 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28010 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28011 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28013 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28014 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28016 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28019 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28020 674 31 09:47:25 ? 00:00:01 com.example.flutterlayouttest
u0_a234 27992 28021 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28022 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28023 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28024 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28025 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28026 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28027 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28028 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28029 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28030 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28031 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28034 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28035 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28036 674 31 09:47:25 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28307 674 31 09:49:59 ? 00:00:00 com.example.flutterlayouttest
更优雅的命令应该是加上-p pid
raphael:/ # ps -AfT -p 27992
UID PID TID PPID TCNT STIME TTY TIME CMD
u0_a234 27992 27992 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 27998 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28003 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28004 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28005 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28006 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28007 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28008 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28009 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28010 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28011 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28013 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28014 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28016 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28019 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28020 674 31 47:24 ? 00:00:01 com.example.flutterlayouttest
u0_a234 27992 28021 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28022 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28023 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28024 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28025 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28026 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28027 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28028 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28029 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28030 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28031 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28034 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28035 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28036 674 31 47:24 ? 00:00:00 com.example.flutterlayouttest
u0_a234 27992 28307 674 31 49:58 ? 00:00:00 com.example.flutterlayouttest
贴上对应help
1|raphael:/ # ps --help
usage: ps [-AadefLlnwZ] [-gG GROUP,] [-k FIELD,] [-o FIELD,] [-p PID,] [-t TTY,] [-uU USER,]List processes.
Which processes to show (-gGuUpPt selections may be comma separated lists):
-A All -a Has terminal not session leader
-d All but session leaders -e Synonym for -A
-g In GROUPs -G In real GROUPs (before sgid)
-p PIDs (--pid) -P Parent PIDs (--ppid)
-s In session IDs -t Attached to selected TTYs
-T Show threads also -u Owned by selected USERs
-U Real USERs (before suid)Output modifiers:
-k Sort FIELDs (-FIELD to reverse) -M Measure/pad future field widths
-n Show numeric USER and GROUP -w Wide output (don't truncate fields)Which FIELDs to show. (-o HELP for list, default = -o PID,TTY,TIME,CMD)
-f Full listing (-o USER:12=UID,PID,PPID,C,STIME,TTY,TIME,ARGS=CMD)
-l Long listing (-o F,S,UID,PID,PPID,C,PRI,NI,ADDR,SZ,WCHAN,TTY,TIME,CMD)
-o Output FIELDs instead of defaults, each with optional :size and =title
-O Add FIELDS to defaults
-Z Include LABEL
一共是31个线程
raphael:/ # ps -AfT -p 27992|wc -l
32
对比普通Android 计算器有17个线程
1|raphael:/ # ps -A | grep calcula
u0_a220 28589 674 5293336 150952 SyS_epoll_wait 0 S com.miui.calculator
raphael:/ # ps -AfT -p 28589|wc -l
18
2.2 加载流程
PostFork + ZygoteInit + ActivityThreadMain
bindApplication + activityStart
其中ResourcesManager#applyConfigurationToResourcesLocked
花了50ms，挺长的
activityStart花了100ms
activity resume
没看到绘制页面的相关堆栈呀。。。只看到有个叫做ui的线程，这个是干啥的。。。
这里显示启动花了394ms
systemserver显示加载应用花了378ms
surfaceflinge也看不出什么花来
应该是atrace的category设置的不对，以Settings的WiFi界面抓取trace
选上
atrace_categories: "gfx"
atrace_categories: "view"
atrace_categories: "wm"
atrace_categories: "am"
atrace_categories: "rs"
atrace_categories: "pm"就好了
再次抓取
可以看到对应的布局都显示出来了，使用了线程布局 + ViewStub + Framelayout
activityResume后Choreographer#doFrame，包含熟悉的measure+layout + draw过程
渲染线程在下面
3.总结
flutter的启动后总线程数比一般Android应用多，达到31个
启动过程PostFork + ZygoteInit + ActivityThreadMain + bindApplication + activityStart + activityResume + Choreographer#doFrame(measure + layout + draw)
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