[ltt-dev] [URGENT]Re: Flight Recorder Testing on Linux-2.6.32

[srikanth krishnakar]

Thanks Mathieu,

I understood now. But where exactly the* lttd with -f and -d* options are
used ? Does this really help out in dynamic buffer extraction ??

-srikant

On Wed, May 26, 2010 at 6:54 PM, Mathieu Desnoyers <
compudj at krystal.dyndns.org> wrote:

> * srikanth krishnakar (skrishnakar at gmail.com) wrote:
> > Hello Mathieu,
> >
> > In the analysis of COREDUMP using *FLIGHT_RECORDER*, what are the steps I
> do
> > need to follow for tracing, because If i follow the steps :
> >
> > 1. Connect all markers (ltt-armall)
> >
> > 2. Start tracing (lttctl -Cw /tmp/trace1 trace1)
> >
> > *Till here every thing is fine... w.r.t  trace methods involved. Now say
> If
> > here I get KERNEL_PANIC, then what about my trace data that is still
> pending
> > and needs to be written to files.*
> > *I mean till I destroy the channels I will not get the trace data !! *
> >
> > How do I resolve this situation !!! where kernel panics and no trace data
> > available for user ?
>
> You would need support to get your buffers from a crash dump extraction
> tool (e.g. "crash"). There has been some work done on this in the past
> by Fujitsu, but that was a few years ago, so I doubt it's aware of the
> current LTTng buffer layout. So this is currently unsupported. Patches
> are welcome. :)
>
> Thanks,
>
> Mathieu
>
> >
> > Any input are appreciated !!
> >
> > Thanks,
> > Srikant
> >
> >
> > On Mon, May 24, 2010 at 6:59 PM, srikanth krishnakar
> > <skrishnakar at gmail.com>wrote:
> >
> > > Hi Mathieu,
> > >
> > > I am trying to run through the LTTng Flight Recorder test on kernel
> > > Linux-2.6.32.13.  Here are the steps I have followed :
> > >
> > >
> > > 1. Compiled the kernel Linux-2.6.32 + Lttng support
> > >
> > > 2. Booted the Lttng kernel
> > >
> > > 3. Loaded all the necessary modules, followed by :
> > >
> > > 4. Ran "ltt-armall"
> > >
> > > 5. Then started the tracing in flight recorder mode as:
> > >
> > > #  lttctl -C -w /tmp/trace3 -o channel.all.overwrite=1 trace3
> > >
> > > 6. Then destroyed the channels, for write process to take place:
> > >
> > > # lttctl -D trace3
> > >
> > >
> > > Correct me If i am going wrong in any of the above steps, that are
> > > necessary for flight recorder testing.
> > >
> > > What is the difference do I find in normal LTTng tracing and the Flight
> > > Recorder mode ? What difference does the LTTV-GUI shows for LTTng
> Flight
> > > recorder mode ?
> > > (Is LKCD any way related to core dump tracing in Flight Recorder mode
> ?)
> > >
> > > Are there any additional steps required for carrying out the tracing in
> > > Flight recorder mode for CORE DUMP tracing.
> > >
> > > All the steps i have followed are from :
> > >
> http://lttng.org/cgi-bin/gitweb.cgi?p=lttv.git;a=blob_plain;f=LTTngManual.html#flight
> > >
> > > Any pointers would be appreciated !!
> > >
> > > Thanks in Advance !
> > >
> > > Regards
> > > Srikanth Krishnakar
> > > **********************
> > >
> >
> >
> >
> > --
> > "The Good You Do, The Best You GET"
> >
> > Regards
> > Srikanth Krishnakar
> > **********************
>
> --
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
>



-- 
"The Good You Do, The Best You GET"

Regards
Srikanth Krishnakar
**********************
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