Android - Problems with logging the start up latency

Question

I am trying to log the start up latency of my app. They way I am doing it is setting the start time of the app on Application.onCreate and provide a public method that returns the time.

MyApplication extends Application {
    Date startUpTime;
    //Declare variables
    @Override
    public void onCreate() {
        super.onCreate();
        setStartupTime();
        //other initializations
    }

    private void setStartUpTime() {
        startUpTime = new Date();
    }

    public Date getStartUpTime() {
        return startUpTime;
    }
}

MyActivity extends Activity {
.
.
.
    @Override
    public void onStart(){
        logStartUpLatency();
        //other onStart stuff
    }

    private void logStartUpLatency() {
        Date currentTime = new Date();
        Date startTime = (MyApplication)getApplicationContext().getStartUpTime();
        long latency = currentTime.getTime() - startTIme.getTime();
        Log.d("Start up Latency is ", Long.toString(latency)):

    }

This is how I am testing my start up latency:

adb install myapk
run the app to get the first start up latency. I can see the latency logged is correct for the first start
run the app again to test the start latency. The latency logged is correct for the start(or any number of subsequent starts)
Now I increase my app's version code and name by 1. To simulate an upgrade, I used the command adb install -r myapk.
Now I run the app again to test the first start latency after upgrade, even though it takes 3 seconds, the latency logged is off the charts.

Does any one know why that might happen?

Update

So if I install the apk using "adb install -r myapk", the app isn't going through the Myapplication.onCreate().

score 10 · Answer 1 · answered Apr 12 '15 at 11:39

I suggest the use of the TimingLogger class. As per the documentation, you can easily track the elapsed time and even add splits in the process.

This

TimingLogger timings = new TimingLogger(TAG, "methodA");
// ... do some work A ...
timings.addSplit("work A");
// ... do some work B ...
timings.addSplit("work B");
// ... do some work C ...
timings.addSplit("work C");
timings.dumpToLog();

produces

D/TAG (3459): methodA: begin
D/TAG (3459): methodA:      9 ms, work A
D/TAG (3459): methodA:      1 ms, work B
D/TAG (3459): methodA:      6 ms, work C
D/TAG (3459): methodA: end, 16 ms

score 0 · Answer 2 · answered Apr 11 '15 at 15:50

The latency you are calculating is in milliseconds. Date#getTime() returns the number of milliseconds since Jan. 1, 1970, midnight GMT.

The observed time of 3 seconds is because of the overhead for uninstalling the old and installing the new app build.

score 0 · Accepted Answer · answered Apr 12 '15 at 23:02

So if I install the apk using "adb install -r myapk", the app isn't going through the Myapplication.onCreate(). So that answers this question. I will ask a separate question on why installing an application using "adb install -r myapk" and then starting myapk doesn't go through MyApplication.onCreate()

Android - Problems with logging the start up latency

3 Answers3