How do I use async_start and async_stop in systrace/atrace for Android

问题

I want to capture Systrace report on my Android phone while doing automated testing. It is unknown how long the testing will take, so I can't specify the --time period for the Systrace.

Digging deeper in to the systrace.py, I found out that systrace is using atrace to get the kernel logs.

I used adb shell atrace --help and got the following output:

usage: atrace [options] [categories...]
options include:
  -a appname      enable app-level tracing for a comma separated list of cmdlines
  -b N            use a trace buffer size of N KB
  -c              trace into a circular buffer
  -k fname,...    trace the listed kernel functions
  -n              ignore signals
  -s N            sleep for N seconds before tracing [default 0]
  -t N            trace for N seconds [defualt 5]
  -z              compress the trace dump
  --async_start   start circular trace and return immediatly
  --async_dump    dump the current contents of circular trace buffer
  --async_stop    stop tracing and dump the current contents of circular
                    trace buffer
  --list_categories
                  list the available tracing categories

How can I use atrace to start tracing at the beginning of my automated testing, and stop the tracing and dumping the kernel log at the end of my automated testing?

I tried using the following commands, but I don't think it works properly. Only async_dump gives me some data in the log. async_stop dump doesn't have any content in the log. How do I properly start the trace, dump it, and then stop it?

adb shell atrace -b 10000 -c am shedgfx view --async_start > C:\Users\user1\Desktop\log.txt 

adb shell atrace -b 10000 -c am shedgfx view --async_dump  > C:\Users\user1\Desktop\log.txt 

adb shell atrace -b 10000 -c am shedgfx view --async_stop > C:\Users\user1\Desktop\log.txt 

回答1:

1. schedgfx should probably be 2 separate calls: sched and gfx. See the output from your device when running:

   $ adb shell atrace --list_categories

2. The categories should be the last part of the command line (in your commands, the categories are placed before the async_* options):

   $ adb shell atrace --help usage: atrace [options] [categories...] options include: -a appname enable app-level tracing for a comma separated list of cmdlines -b N use a trace buffer size of N KB -c trace into a circular buffer -k fname,... trace the listed kernel functions -n ignore signals -s N sleep for N seconds before tracing [default 0] -t N trace for N seconds [defualt 5] -z compress the trace dump --async_start start circular trace and return immediatly --async_dump dump the current contents of circular trace buffer --async_stop stop tracing and dump the current contents of circular trace buffer --list_categories list the available tracing categories

3. The tool runs on a circular buffer, so each time you run the dump command, you'll only get whatever contents are in the buffer at that time. In the Espresso rules:0.5 package (assuming you are using Espresso), there is an AtraceLogger class that can help automate this for you as part of your test harness, by calling the atraceStart(...) method:

   public void atraceStart(Set<String> traceCategoriesSet, int atraceBufferSize, int dumpIntervalSecs, File destDirectory, String traceFileName) throws IOException

   You can do that by creating a @Rule or @ClassRule, or hook into it some other way such as with a TestRunner:

   @Override
   protected void before() throws Throwable {
       mAtrace = AtraceLogger.getAtraceLoggerInstance(InstrumentationRegistry.getInstrumentation());
       mAtrace.atraceStart(new HashSet<>(Arrays.asList("gfx", "sched", ...)),
               1024 /* bufferSize */, 1 /* dump interval */,
               RuleLoggingUtils.getTestRunDir(), "filename");
   }
   
   @Override
   protected void after() {
       try {
           mAtrace.atraceStop();
       } catch (IOException e) {
           Log.w(TAG, "Failed to stop Atrace", e);
       } catch (InterruptedException e) {
           Log.w(TAG, "Failed to stop Atrace", e);
       }
   }
   

   The RuleLoggingUtils.getTestRunDir() method will place the captured dump files into the external files path for your app, so you can pull those files after the test is finished, using:

   $ adb pull /sdcard/Android/data/com.yourcompany.package/files/testdata/

And each atrace file can then be inspected using the systrace viewer by running systrace with the --from-file=<trace file> option.

来源：https://stackoverflow.com/questions/31192104/how-do-i-use-async-start-and-async-stop-in-systrace-atrace-for-android