Android debug traces do not contain application specific method calls

问题

I am trying to generate trace files for applications using the Debug.startMethodTracing (on the activity onCreate) and Debug.stopMethodTracing (on the activity onDestroy) according to the following documentation http://developer.android.com/tools/debugging/debugging-tracing.html#creatingtracefiles.

I run the application on a physical device and it successfully creates the trace file. Later I run dmtracedump on them to generate a call-stack diagram, but it does not contain any of my application method calls.

To test this, I created a simple Android application, added debbuggable to the manifest:

 <application
    ... 
    android:debuggable="true">

Created two test classes A and B. Class A has two methods b() and c():

public class A {

private int _i;

public A(){_i=0;}

public void b(){c();}
public void c(){for(int k=0;k<20;k++)_i++;}}

Class B has a single method c():

public class B {

public void c(){
    (new A()).b();
    A d = new A();
    d.c();
}}

Finally in the main activity on the onCreate and onDestroy methods I started the tracing:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Debug.startMethodTracing("debugtest");

    A a;
    for (int i = 0; i < 20; i++) {
        a = new A();
        a.b();
        a.c();
    }

    (new B()).c();
}

@Override
public void onDestroy() {
    super.onDestroy();
    Debug.stopMethodTracing();
}

I was hoping to get at least A.b() and A.c() method calls in the call stack diagram but after running:

adb pull sdcard/debugtest.trace . ; dmtracedump debugtest.trace -g tree.png

The generated call graph is as follows:

Is this how it is supposed to work, i.e. just show android calls and not application method calls, or am I missing something?

Please note that i am mostly interested in retrieving the exclusive and inclusive times of method execution.

回答1:

It might be because (by default) the -t option of traceview is set to 20%. From AndroidStudio dmtracedump

-t : Minimum threshold for including child nodes in the graph (child's inclusive time as a percentage of parent inclusive time). If this option is not used, the default threshold is 20%.

If you open your trace file with traceview you'll see that your graph is something like:

the first node of your graph is the first method call
the second of your graph is the first child of the first call in traceview
the third of your graph is the first child of the child of the first method call
and so on...

Run dmtracedump with -t 0 (as follows) and you should see all the methods.

dmtracedump -t 0 debugtest.trace -g tree.png

回答2:

You can get more information by placing e.getStacktrace() or using a Log in your classes. I find it's easier to explicitly ask for the errors than hoping the code will just come to you. Of course there is probably a much better way but that is how I've been doing it for a while and I've been able to get a really consistent and easy to pinpoint result.

来源：https://stackoverflow.com/questions/20571324/android-debug-traces-do-not-contain-application-specific-method-calls

标签

android

profiling

trace

call-graph