关于 android 通过 python 统计 fps

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本文介绍了一种使用Python脚本配合第三方库统计Android设备上应用FPS的方法。通过调用adb命令并利用SurfaceFlinger组件获取帧率数据，该脚本能够帮助开发者分析应用性能，并提供了一个简单的例子来演示如何计算平均FPS。

用了这个第三方库
https://github.com/ChromiumWebApps/chromium/tree/master/build/android/pylib

然后如下代码：

<span class="c"># -*- coding: utf8 -*-</span>
<span class="kn">import</span> <span class="nn">os</span><span class="o">,</span> <span class="nn">time</span><span class="c">#, sys</span>
<span class="kn">from</span> <span class="nn">pylib</span> <span class="kn">import</span> <span class="n">android_commands</span><span class="p">,</span> <span class="n">surface_stats_collector</span>

<span class="n">resultList</span> <span class="o">=</span> <span class="p">[]</span>
<span class="n">deviceText</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">popen</span><span class="p">(</span><span class="s">'adb devices'</span><span class="p">)</span>
<span class="n">textList</span> <span class="o">=</span> <span class="n">deviceText</span><span class="o">.</span><span class="n">readlines</span><span class="p">()</span>
<span class="n">deviceName</span> <span class="o">=</span> <span class="n">textList</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span><span class="o">.</span><span class="n">split</span><span class="p">()[</span><span class="mi">0</span><span class="p">]</span>
<span class="n">adb</span> <span class="o">=</span> <span class="n">android_commands</span><span class="o">.</span><span class="n">AndroidCommands</span><span class="p">(</span><span class="n">deviceName</span><span class="p">)</span>
<span class="n">collector</span> <span class="o">=</span> <span class="n">surface_stats_collector</span><span class="o">.</span><span class="n">SurfaceStatsCollector</span><span class="p">(</span><span class="n">adb</span><span class="p">,</span> <span class="n">activityName</span><span class="p">,</span><span class="mf">0.5</span><span class="p">)</span>
<span class="n">collector</span><span class="o">.</span><span class="n">DisableWarningAboutEmptyData</span><span class="p">()</span>
<span class="n">collector</span><span class="o">.</span><span class="n">Start</span><span class="p">()</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">50</span><span class="p">):</span>    <span class="c">#循环50次，主要方便自己的实现，其他实现方法请另行实现；</span>
    <span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.3</span><span class="p">)</span>
    <span class="n">results</span> <span class="o">=</span> <span class="n">collector</span><span class="o">.</span><span class="n">SampleResults</span><span class="p">()</span>
    <span class="k">if</span> <span class="ow">not</span> <span class="n">results</span><span class="p">:</span>
        <span class="k">pass</span>
    <span class="k">else</span><span class="p">:</span> 
        <span class="n">resultList</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="nb">int</span><span class="p">(</span><span class="n">results</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">value</span><span class="p">))</span>
        <span class="n">results</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">print_str</span><span class="p">()</span>
<span class="n">collector</span><span class="o">.</span><span class="n">Stop</span><span class="p">()</span>
<span class="n">a</span> <span class="o">=</span> <span class="n">resultList</span><span class="p">[</span><span class="mi">3</span><span class="p">:</span><span class="o">-</span><span class="mi">3</span><span class="p">]</span>
<span class="k">print</span> <span class="s">u"平均值："</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="nb">float</span><span class="p">(</span><span class="nb">sum</span><span class="p">(</span><span class="n">a</span><span class="p">)</span><span class="o">/</span><span class="nb">len</span><span class="p">(</span><span class="n">a</span><span class="p">)))</span><span class="o">+</span><span class="s">u" ; 最小值："</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="nb">min</span><span class="p">(</span><span class="n">a</span><span class="p">))</span>

代码写得不怎的，请无视。

运行上述脚本，在对应的activity操作，即可统计当前操作的fps值了。

跑一边看看：

看库的源码，原理是使用"adb shell dumpsys SurfaceFlinger --latency <window name>"进行循环统计实现的。

代码中有如下注释：

<span class="k">def</span> <span class="nf">_GetSurfaceFlingerFrameData</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
    <span class="s">"""Returns collected SurfaceFlinger frame timing data.

    Returns:
      A tuple containing:
      - The display's nominal refresh period in seconds.
      - A list of timestamps signifying frame presentation times in seconds.
      The return value may be (None, None) if there was no data collected (for
      example, if the app was closed before the collector thread has finished).
    """</span>
    <span class="c"># adb shell dumpsys SurfaceFlinger --latency <window name></span>
    <span class="c"># prints some information about the last 128 frames displayed in</span>
    <span class="c"># that window.</span>
    <span class="c"># The data returned looks like this:</span>
    <span class="c"># 16954612</span>
    <span class="c"># 7657467895508   7657482691352   7657493499756</span>
    <span class="c"># 7657484466553   7657499645964   7657511077881</span>
    <span class="c"># 7657500793457   7657516600576   7657527404785</span>
    <span class="c"># (...)</span>
    <span class="c">#</span>
    <span class="c"># The first line is the refresh period (here 16.95 ms), it is followed</span>
    <span class="c"># by 128 lines w/ 3 timestamps in nanosecond each:</span>
    <span class="c"># A) when the app started to draw</span>
    <span class="c"># B) the vsync immediately preceding SF submitting the frame to the h/w</span>
    <span class="c"># C) timestamp immediately after SF submitted that frame to the h/w</span>
    <span class="c">#</span>
    <span class="c"># The difference between the 1st and 3rd timestamp is the frame-latency.</span>
    <span class="c"># An interesting data is when the frame latency crosses a refresh period</span>
    <span class="c"># boundary, this can be calculated this way:</span>
    <span class="c">#</span>
    <span class="c"># ceil((C - A) / refresh-period)</span>
    <span class="c">#</span>
    <span class="c"># (each time the number above changes, we have a "jank").</span>
    <span class="c"># If this happens a lot during an animation, the animation appears</span>
    <span class="c"># janky, even if it runs at 60 fps in average.</span>
    <span class="c">#</span>
    <span class="c"># We use the special "SurfaceView" window name because the statistics for</span>
    <span class="c"># the activity's main window are not updated when the main web content is</span>
    <span class="c"># composited into a SurfaceView.</span>
    <span class="n">results</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_adb</span><span class="o">.</span><span class="n">RunShellCommand</span><span class="p">(</span><span class="s">'dumpsys SurfaceFlinger --latency '</span> <span class="o">+</span> <span class="bp">self</span><span class="o">.</span><span class="n">_activity</span><span class="p">)</span>
    <span class="k">if</span> <span class="ow">not</span> <span class="nb">len</span><span class="p">(</span><span class="n">results</span><span class="p">):</span>
      <span class="k">return</span> <span class="p">(</span><span class="bp">None</span><span class="p">,</span> <span class="bp">None</span><span class="p">)</span>

英语烂，脑容量有限，一直看不明白，有大神帮帮忙解析一下哈（原谅我伸手党）。

=================================================以下是回复帖=================================================================

循环50次，间隔0.3s，得到50个数据。然后掐头去尾，计算下平均值。好像是大概10s内的fps平均值。
adb shell dumpsys SurfaceFlinger 本身能打印出fps 里面会有更细致的帧数计算数据。细节我也了解的不太多。

surface_stats_collector.SurfaceStatsCollector函数里面应该有你想要的逻辑。你可以帖一下欣赏下。

一般某个过程发生了丢帧, 是在几秒内的, 10s有点太长, 不过还可以接受. 大部分的卡顿都在2s以上. 10s内平均也能差不多通过平均值看出来.