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From "Alex Karasulu" <akaras...@apache.org>
Subject Re: Compared profiling sessions between trunk and bbb
Date Thu, 29 May 2008 05:24:28 GMT
On Wed, May 28, 2008 at 9:06 PM, Emmanuel Lecharny <elecharny@apache.org>
wrote:

> Hi guys,
>
>
> yesturday, I spent some time running my own little test - I still have to
> create a project to store this test btw - on the bigbang branch, to compare
> what we get with what we have on trunk.
>
> Basically, without an once of optimization, trunk is 55% faster than bbb
> (5000 search req/s against 3200 search req/s).
>
> So where do we eat too much CPU in bbb ?
>
> The big difference is in method :
> org.apache.directory.server.core.jndi.ServerDirContext.search(Name,
> ExprNode, SearchControls)
>
> For 10 000 searches, it costs 433 seconds in bbb and 218 seconds in trunk
> (so it's two time slower). Not a surprise :) What is interesting is that in
> bbb, this method spend one third of its time (120secs) calling this method :
> org.apache.directory.server.core.jndi.NamingEnumerationAdapter.<init>(EntryFilteringCursor)
>
> (this method does not exist in trunk).
>
> Down the stack, after having passed through all the interceptors, the
> search() method doing the entries retrieval from the backend cost _exactly_
> the same in bbb : 39 seconds in bbb, 40 seconds in trunk. Considering that
> this part has not been optimized at all, this is quite a good news.
>
> So what's the biggest difference ?
>
> We have this method call in bbb :
> org.apache.directory.server.core.filtering.BaseEntryFilteringCursor.next()
>
> that is not present in trunk. It consumes 211 seconds. This is where we are
> filtering all the entries. The bad thing is that entries are cloned at least
> three times, and this is a VERY costly operation. It's easy to improve.
>
> Base line is that I'm really confident that we will quickly get some great
> improvement in bbb, and I'm also pretty confident that we will be able to
> make bbb faster than trunk.
>
> More to come later this week !
>

Thanks Emmanuel for this report.  I'm eager to start looking into how we can
fix some of these problems you've found.

Alex

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