Android 常用的性能分析工具详解：GPU呈现模式, TraceView, Systrace, HirearchyViewer

//在开始调试的地方，如Activity的onCreate函数，添加
Debug.startMethodTracing("tracefilename");//结束调试的地方，如Activity的onDestroy函数，添加
Debug.stopMethodTracing();

运行app一段时间后，再点击已变成stop method profiling的该按钮。eclipse会自动弹出debug的标签(可通过菜单File->save as保存数据), 界面同上面。这种方式不需要修改代码，所以对于没有源码的程序同样可以进行排查。同时可以方便的进行全局性能排查。

2. TraceView界面信息介绍。TraceView界面包括时间面板和方法面板
(1) 时间面板(Timeline Panel)
时间面板展示了每个线程的执行情况，其中的[1]main即为ui主线程。
移动到某个位置可以查看该点对应的方法的执行信息，点击方法面板则会选中相应的方法。
可以左键按住不放选中区域放大局部精细查看，不同方法用不同颜色标注
 
(2) 方法面板(Profile Panel)
方法面板展示了所有方法的执行情况，点击某个方法可以查看在对应线程上的执行时间区域，并会显示其父方法及子方法。
每个方法包括如下信息列，可点击某列进行排序，从而确定产生性能问题的函数：

Incl Cpu Time
Excl Cpu Time
Incl Real Time
Excl Real Time
Incl Cpu Time%
Excl Cpu Time%
Incl Real Time%
Excl Real Time%
Calls+RecurCalls/Total
Cpu Time/Call 
Real Time/Call

• 内核部分：Systrace利用了Linux Kernel中的ftrace功能。所以，如果要使用Systrace的话，必须开启kernel中和ftrace相关的模块。
• 数据采集部分：Android定义了一个Trace类。应用程序可利用该类把统计信息输出给ftrace。同时，Android还有一个atrace程序，它可以从ftrace中读取统计信息然后交给数据分析工具来处理。
• 数据分析工具：Android提供一个systrace.py（python脚本文件，位于Android SDK目录/tools/systrace中，其内部将调用atrace程序）用来配置数据采集的方式（如采集数据的标签、输出文件名等）和收集 ftrace统计数据并生成一个结果网页文件供用户查看。

• UsingEclipse

1. In Eclipse, open an Android application project.
2. Switch to the DDMS perspective, by selecting Window > Perspectives > DDMS.
In the Devices tab, select the device on which to run a trace. If no devices are listed, make sure your device is connected via USB cable and that debugging is enabled on the device.
3. Click the Systrace icon at the top of the Devices panel to configure tracing.
4. Set the tracing options and click OK to start the trace.

1. In Android Studio, open an Android application project.
2. Open the Device Monitor by selecting Tools > Android > Monitor.
3. In the Devices tab, select the device on which to run a trace. If no devices are listed, make sure your device is connected via USB cable and that debugging is enabled on the device.
4. Click the Systrace icon at the top of the Devices panel to configure tracing.
5. Set the tracing options and click OK to start the trace.

• UsingDevice Monitor

1. Navigate to your SDK tools/ directory.
2. Run the monitor program.
3. In the Devices tab, select the device on which to run a trace. If no devices are listed, make sure your device is connected via USB cable and that debugging is enabled on the device.
4. Click the Systrace icon at the top of the Devices panel to configure tracing.
5. Set the tracing options and click OK to start the trace.

• Command Line Usage

Usage: systrace.py [options] [category1 [category2 ...]]
Example: systrace.py -b 32768 -t 15 gfx input view sched freq
Options:-h, --help            show this help message and exit-o FILE               write HTML to FILE-t N, --time=N        trace for N seconds-b N, --buf-size=N    use a trace buffer size of N KB-k KFUNCS, --ktrace=KFUNCSspecify a comma-separated list of kernel functions totrace-l, --list-categorieslist the available categories and exit-a APP_NAME, --app=APP_NAMEenable application-level tracing for comma-separatedlist of app cmdlines--link-assets         link to original CSS or JS resources instead ofembedding them--from-file=FROM_FILEread the trace from a file (compressed) rather thanrunning a live trace--asset-dir=ASSET_DIR-e DEVICE_SERIAL, --serial=DEVICE_SERIALadb device serial number

Key	Description
w	Zoom into the trace timeline.
s	Zoom out of the trace timeline.
a	Pan left on the trace timeline.
d	Pan right on the trace timeline.
e	Center the trace timeline on the current mouse location.
g	Show grid at the start of the currently selected task.
Shift+g	Show grid at the end of the currently selected task.
Right Arrow	Select the next event on the currently selected timeline.
Left Arrow	Select the previous event on the currently selected timeline.
Double Click	Zoom into the trace timeline.
Shift+Double Click	Zoom out of the trace timeline.

Trace.traceBegin(Trace.TRACE_TAG_VIEW, "performTraversals");
try {//TODO your work
} finally {Trace.traceEnd(Trace.TRACE_TAG_VIEW);
}