[lttng-dev] LTTng Android support now in Cyborgstack

Karim Yaghmour karim.yaghmour at opersys.com
Fri Feb 24 16:32:18 EST 2012

The work I had done on getting LTTng to work with Android is now on 

$ repo init -u git://github.com/cyborgstack/android.git -b lttng
$ repo sync
$ ...

You'll find the required kernel patch in misc/. It should apply cleanly 
on the 2.6.29 used for the emulator.

Once built, you can do something like this to use lttng:
$ adb shell
/ # ltt-armall
/ # lttctl -C -w /data/local/trace1 trace1
/ # am start -a android.intent.action.VIEW -d http://www.opersys.com
/ # lttctl -D trace1
/ # cd /data/local
/data/local # tar cvzf trace1.tar.gz trace1


$ adb pull /data/local/trace1.tar.gz
$ tar xvzf trace1.tar.gz
$ ...

I'm using:
lttng control tools 0.75-15112009
lttng viewer tools v0.12.20

As mentioned elsewhere, I'm not using lttng's user-space RCU tracing. 
Though I wish. Instead, I'm using the /mnt/debugfs/ltt/write_event, 
which somewhat pollutes the trace.

As I mentioned in my ABS keynote two Mondays ago, I think Android is a 
case-in-point of why lttng's holistic approach to tracing shines in 
comparison to many other tracing mechanisms out there; if nothing else 
because of the ability to use the user-space RCU tracing -- albeit it 
isn't being used in this specific case.

Karim Yaghmour
CEO - Opersys inc. / www.opersys.com

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