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Posted to java-user@lucene.apache.org by Paul Hill <pa...@metajure.com> on 2012/06/11 18:56:05 UTC

RE: CPU usage increased using 3.4.0

Maybe someone already discussed this, but why is 100% usage a problem? I ask, because one interpretation of going from 30% usage to 100% usage is that the program is no longer I/O bound; it is no longer waiting around for I/O to complete. But maybe that is not what you mean.  If the total elapsed run-time is down then you have gained something.  If you need to share the CPU with others, I would think this is mostly an OS question.  If the CPU usage is up because of better OS file buffer usage, you might find that another application could share the OS with little change to the JVM running the crawl.  The crawl application might slow down when fewer files buffers are already in the OS file memory cache.

-Paul

> I have wrote a crawling and indexing program using 3.0.3 version. It works fine. CPU usage remain around
> 30%. In November, 2011 I have upgraded Lucene
> 3.4.0 version, trying crawling and indexing with this version, it increased CPU usage to 100%. Can any one
> please help me out about decreasing CPU usage.
> What are the settings to be done in Lucene to decrease CPU usage.

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Re: CPU usage increased using 3.4.0

Posted by Jack Krupansky <ja...@basetechnology.com>.
Is the process taking longer or even a lot longer than with the earlier 
release of Lucene?

Is the amount of available JVM memory so low that repeated garbage 
collections might be occurring?

-- Jack Krupansky

-----Original Message----- 
From: Paul Hill
Sent: Monday, June 11, 2012 12:56 PM
To: java-user@lucene.apache.org
Subject: RE: CPU usage increased using 3.4.0

Maybe someone already discussed this, but why is 100% usage a problem? I 
ask, because one interpretation of going from 30% usage to 100% usage is 
that the program is no longer I/O bound; it is no longer waiting around for 
I/O to complete. But maybe that is not what you mean.  If the total elapsed 
run-time is down then you have gained something.  If you need to share the 
CPU with others, I would think this is mostly an OS question.  If the CPU 
usage is up because of better OS file buffer usage, you might find that 
another application could share the OS with little change to the JVM running 
the crawl.  The crawl application might slow down when fewer files buffers 
are already in the OS file memory cache.

-Paul

> I have wrote a crawling and indexing program using 3.0.3 version. It works 
> fine. CPU usage remain around
> 30%. In November, 2011 I have upgraded Lucene
> 3.4.0 version, trying crawling and indexing with this version, it 
> increased CPU usage to 100%. Can any one
> please help me out about decreasing CPU usage.
> What are the settings to be done in Lucene to decrease CPU usage.

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