[ltt-dev] Flight-recording mode

[Gerlando Falauto]

Hi all,

after a little experimenting with LTTng 0.x on kernel 2.6.33,
I am doing some further investigation on LTTng 2.x on kernel 3.0.

I am still missing something though on both versions though.
I would assume that in /pure/ flight-recording mode, everything would be 
buffered by LTTng on kernel side.

Here's what I am doing on LTTng 2.x:

# lttng create trace
Spawning a session daemon
Session trace created.
Traces will be written in /root/lttng-traces/trace-19700101-000039

# lttng enable-channel myc -k --overwrite --subbuf-size=4096 
--num-subbuffers=4
Channel enabled myc for session trace

# lttng enable-event sched_switch,sched_wakeup -k -c myc
Kernel event sched_switch created in channel myc
Kernel event sched_wakeup created in channel myc

# lttng start
Tracing started for session trace

However, I still get files which are constantly, unreasonably growing in 
my /root/lttng-traces/trace-19700101-000039
I also tried enabling the channel *after* enabling the events, but with 
the same end result.

How can I make sure that only the latest N seconds of traces will be 
saved? The answer should be flight-recording mode, but how do I really 
do it?

Thanks!
Gerlando