----------------------------------------------------------------------
Date: Tue, 4 Feb 2014 12:17:36 -0500
From: David Goulet <[email protected]>
To: Jim Dumont <[email protected]>
Cc: "[email protected]" <[email protected]>

>> 3) add-context: does --jul have the same possible context types as 
>> --userspace (i.e. ip, pthread_id, procname, vpid, vtid)?
>
> Nope.

   What are the possible context types then?  Or is it just that you can't 
apply a filter to a jul event?

>> 4) enable-channel:
>> 4.1) Are the --jul --subbuf-size, --num-subbuf and --read-timer defaults the 
>> same as with --userspace?
>
> Nope. JUL uses it's internal channel so basically enable channel does NOT 
> support the jul domain thus not having -j in the help/man.

   So you turn jul events on and off using enable/disable-event --all instead?  
This is getting a tad confusing: jul events force you to use only 
enable/disable-event but kernel syscalls force you to use only 
enable/disable-channel...

>> 4.4) If yes, won't they all degenerate to the virtual machine's user and 
>> process IDs?
>
> Not sure I understand this one?

   A Java application is interpreted and runs in a Java virtual machine (JVM).  
The userID and processID of any jul events are thus likely to be those of the 
JVM process.  I would expect Java apps launched by separate users to launch 
separate JVM instances, but I would also expect two separate Java apps launched 
by the same user to share a single JVM (the user's) and, therefore, their 
process IDs.  This could get fun with multi-threaded Java apps.

> Now after answering all this, I feel like either creating a lttng-jul man 
> page or adding a special section in "lttng.1" for the JUL domain explaining 
> all this. Thoughts?

   We definitely need an additional section in "lttng.1".

Daniel U. Thibault
Protection des systèmes et contremesures (PSC) | Systems Protection & 
Countermeasures (SPC)
Cyber sécurité pour les missions essentielles (CME) | Mission Critical Cyber 
Security (MCCS)
R & D pour la défense Canada - Valcartier (RDDC Valcartier) | Defence R&D 
Canada - Valcartier (DRDC Valcartier)
2459 route de la Bravoure
Québec QC  G3J 1X5
CANADA
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<http://www.valcartier.drdc-rddc.gc.ca/>

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