[lttng-dev] Userspace Tracing

[Francis Giraldeau]

Le 2013-12-13 14:53, Michael Steppe a écrit :
> Hello!
> 
> I have a question regarding userspace tracing. I am working on a project
> on which we have used LTTng in the past (prior to LTTng 2.0). In order
> to see how our application was running in coordination with the kernel,
> we created a .h file in which we would append strings to
> "/mnt/debugfs/ltt/write_event" in order to see our application timing in
> the LTTng viewer in Eclipse.
> 
> Since then we have updated to LTTng 2.0.4. It would be very hard for us
> to change to a different version at the current time. I have noticed
> that /mnt/debugfs/ltt/write_event no longer exists in 2.0.4 and was
> wondering (crossing my fingers) that this location has simply changed or
> is there a new filesystem that you use?

This feature has not been included in lttng 2. I think that this feature
is useful, and I tried last year to bring it back. It was close to be
merged as a separate proc file, but someone pointed that it would be
better to profile the file with debugfs. I haven't work on it since
then. I may give it another spin later, but I can't right now.

http://lists.lttng.org/pipermail/lttng-dev/2012-July/018210.html

Cheers,

Francis