Hello Mathieu, Thanks a lot for your quick response !!
If i interpret your pointers correctly, then I understand, destroying+Appending trace result to previously destroyed trace session will not write matching meta-data to old channels, right ? which further results in difference in event sizes ! So correcting my execution script : ################################### #!/bin/bash mount -t debugfs debugfs /mnt/debug ltt-armall lttctl -C -w /home/root/trace1 trace1 lttctl -s trace1 sleep 2 lttctl -p trace1 #lttctl -D trace1 # Pause and destroy a trace named trace1 and *<<<<< Eliminated the Destroy operation * sleep 10 lttctl -C trace1 -w /home/root/trace1 *-a* *<<< Retain append option for continuation with existing data* lttctl -s trace1 sleep 2 lttctl -p trace1 lttctl -D trace1 ltt-disarmall lttv -m textDump -t /home/root/trace1 ################################### Does it looks OK ? Or still needs correction ? And also one more small doubt regarding difference among '-c' && '-C' options, any significant changes that result after swapping these ? Thanks & Regards -Srikant ---------- On Tue, Dec 21, 2010 at 12:57 AM, Mathieu Desnoyers < [email protected]> wrote: > * srikanth krishnakar ([email protected]) wrote: > > Hello Mathieu, > > > > I am trying to test the append functionality of the ltt-control : > > > > ltt-control : 0.79 > > lttv-0.12.31 > > Linux-2.6.32.9 > > > > ############################################# > > > > #!/bin/sh > > mount -t debugfs debugfs /mnt/debug > > *ltt-armall* > > * > > * > > *lttctl -C -w /home/root/trace1 trace1* > > * > > * > > *lttctl -s trace1* > > sleep 2 > > > > *lttctl -p trace1* > > * > > * > > # Pause and destroy a trace named trace1 and > > "-a" will not work if you stop+destroy a trace session and try appending > to the saved trace from a new trace session. The typical use-case is to > stop tracing (keeping the trace session alive), and then later on start > tracing again (within the same trace session), and there use the -a > switch to append to the existing trace files. > > The problem is that the metadata (event IDs, event sizes, etc) are > supposed to be invariant across a whole trace session, but by appending > to the old trace files, you are combining two trace sessions together > with conflicting metadata. > > Thanks, > > Mathieu > > > > *lttctl -D trace1* > > > > *lttctl -C trace1 -w /home/root/trace1 -a <<<<< Appending > > trace to existing one* > > * > > * > > *lttctl -s trace1* > > sleep 2 > > > > *lttctl -p trace1* > > * > > * > > *lttctl -D trace1* > > * > > * > > *ltt-disarmall* > > > > *lttv -m textDump -t /home/root/trace1* > > * > > * > > *###########################################* > > > > > > Executing the above steps without *'-a'* (append) options works > perfectly > > and i am able to get the trace output after dumping. But the problem lies > in > > when I try to execute with '-a' (append) feature, then the error > displayed > > is difference in kernel event sizes and unable to dump the ouput > > > > > -------------------------------------------------------------------------------- > > ** ERROR **: Kernel/LTTV event size differs for event timer_set: kernel > 11, > > LTTV 12 > > aborting... > > /usr/bin/lttv: line 15: 1516 Aborted $0.real $* > > > -------------------------------------------------------------------------------- > > > > Is there anything missing or am i running out of process that needs to be > > followed to obtain the appended trace result ?? > > > > Is there any info in LTTng user manual that shows the steps to follow for > > using append feature of LTT-CONTROL in kernel tracing ? > > > > Thanks in advance !!! > > -S > > > > > > -- > > "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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