[lttng-dev] Discarded events

[Milian Wolff]

On Sonntag, 13. August 2023 16:58:17 CEST Bala Gundeboina via lttng-dev wrote:
> Hi,
> 
> I am Using LTTng in my project , I am recording a kernel session for long
> duration (eg more than 15minutes) I am enabling all the events for
> recording but some events discarding after stopping the session, if i run
> more than 5 minutes only some events are discarding. I have tried to change
> in the .ltttngrc file also to increase buffer-size.

While not directly related to your question, I strongly encourage you to 
review the list of events and only enable those that are actually required for 
the specific issue you are investigating. Some kernel events are _extremely_ 
high frequency but have often no practical use for many (at least in my 
experience and for my own purposes). Examples for the latter are esp. the 
kmalloc tracepoints.

> lttng destroy
> Destroying session `my-kernel-session`...
> Session `my-kernel-session` destroyed
> Warning: 94424667 events were discarded, please refer to the documentation
> on channel configuration
> 
> actually when i am running below command i am getting below warning i am
> thinking this is the issue because sometimes this warning is not coming
> that i didn't seen discarded events.  how to overcome this problem can you
> provide some detailed lttng-sessiond --daemonize
> Warning: Failed to produce a random seed using getrandom(), falling back to
> pseudo-random device seed generation which will block until its pool is
> initialized: Failed to get true random data using getre
> 
> Thanks & Regards
> Bala Gundeboina
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-- 
Milian Wolff | milian.wolff at kdab.com | Senior Software Engineer
KDAB (Deutschland) GmbH, a KDAB Group company
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