[ltt-dev] limiting LTTng to a certain set of cores

Andrew McDermott andrew.mcdermott at windriver.com
Thu Feb 12 06:50:16 EST 2009


Hi,

> Andrew McDermott wrote:
>> Is there an easy way to limit LTTng to trace a specified set of cores
>> only?  I ask because in some 64+ core systems the data set collected
>> becomes too large for analysis and the tasks to be analyzed are always
>> bound to certain cores (using affinity).
>> 
>
> Out of curiosity, how large is "too large"?

The "too large" actually refers to the volume or quantiy of (displayed)
events.  There are a lot of event related to other cores that are of no
interest.  There's no real issue with processing a multi-gigabyte trace
on the host but there are issues with transferring all 64+ channel trace
files across a very slow link.

What I'm trying to do is filter the set of data that a) needs to be
collected and b) transferred half-way around the world.

-- 
andy




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