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From Manuel Blechschmidt <Manuel.Blechschm...@gmx.de>
Subject Re: Mahout performance issues
Date Thu, 01 Dec 2011 14:56:41 GMT
Hi Daniel,
actually you are running the profile inside tomcat. You should take a snapshot and then drill
down to the functions where the actual recommendation takes place. The current screenshots
also contains some profiles from Tomcat threads which are sleeping a lot and therefore taking
a lot of time.

Further the screenshots does not contain the amount how often the different functions are
called.

You have to profile multiple requests alone. The CacheItemSimilarity gets filled therefore
it should go faster and faster.

On 01.12.2011, at 15:11, Daniel Zohar wrote:

> @Manuel thanks for the tips. I have installed VisualVM and followed are the
> results
> I did two sampling -
> - With the optimized SamplingCandidateItemsStrategy (
> http://pastebin.com/6n9C8Pw1): http://static.inky.ws/image/934/image.jpg
> - Without the optimized SamplingCandidateItemsStrategy:
> http://static.inky.ws/image/935/image.jpg
> 

The big hot spot is the function FastIDSet.find():

Optimized: 13,759 s
Unoptimized: 246,487 s

So you see that your optimization already got you a performance boost of 2000%.

Did you play around with the CacheItemSimilarity cache sizes?

/Manuel

-- 
Manuel Blechschmidt
Dortustr. 57
14467 Potsdam
Mobil: 0173/6322621
Twitter: http://twitter.com/Manuel_B


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