[lttng-dev] How to disable an event that's been enabled by a wildcard selection or -a?

[Woegerer, Paul]

On 05/02/2013 03:40 PM, Mathieu Desnoyers wrote:
> Hi Paul,
> 
> I would be interested to see this feature upstream. Previously was not a
> good timing to pull it in, because we were adding the concept of event
> "enablers" within lttng-ust.

Sounds great. I will port our patch to master.

> 
> One thing I'm curious about is how you present the logical combination
> with exlusion match are present. For instance, if we only have
> inclusion, we get:
> 
> lttng enable-event 'a'
> lttng enable-event 'c'
> lttng enable-event 'zc*'
> 
> it turns into :   (a || c || zc*)
> 
> I expect that negation would look like:
> 
> lttng enable-event 'a'
> lttng enable-event '!abc*'
> lttng enable-event 'c'
> lttng enable-event '!cxx'

Our current solution does not handle '!cxx' correctly.
I will fix that.

> lttng enable-event 'zc*'
> 
> ->  !(abc* || cxx) || (a || c || zc*)

Exactly. The "!something" wildcards are always first and will prevent further matching with non-! wildcards.

> 
> Am I correct ? If yes, we should expand lttng-tools lttng(1) manpage and
> cmd help with this info.

I will take care of documentation updates as well.

> 
> Can you make sure it works well with lttng-ust master branch ?

Once I have a working, tested patch against master I will send it to you.

Thanks,
Paul

-- 
Paul Woegerer | SW Development Engineer
http://go.mentor.com/sourceryanalyzer

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