[rules-users] Parallelization

[Greg Barton]

If you're using the sun VM multiple Threads will use multiple cores just fine.  What version of java?

Are you intending to max out the CPU on the machine?  If so I suggest this configuration, for an 8 core box:

7 Threads, each running a StatefulKnowledgeSession.

Concurrent garbage collection, with VM startup parameters like this:

-XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:MaxGCPauseMillis=150 -XX:+CMSIncrementalMode -XX:+CMSIncrementalPacing -XX:+UseCMSCompactAtFullCollection -XX:CMSFullGCsBeforeCompaction=2 

Here's a good reference for GC parameters: http://java.sun.com/javase/technologies/hotspot/gc/gc_tuning_6.html

And if you're feeling frisky, try out these to see if it improves performance:

-XX:+UseTLAB -XX:+UseSpinning -XX:+UseFastAccessorMethods

The default recommendation for maxing out the CPU is to use <num_cores>+1 Threads, but in this case since garbage collection may be an issue I'd reduce that by two.  You need one core "dedicated" to other stuff (I/O and whatnot) and some resources for GC.

--- On Tue, 5/11/10, djb <dbrownell83 at hotmail.com> wrote:

> From: djb <dbrownell83 at hotmail.com>
> Subject: Re: [rules-users] Parallelization
> To: rules-users at lists.jboss.org
> Date: Tuesday, May 11, 2010, 7:55 AM
> 
> Hi Wolfgang,
> 
> Ok, well I implemented my "option #2", which has cut it
> down to 23ms, which
> is a good start.  My timing is done by taking the time
> before, and after,
> and dividing by the number of claims processed.  (and
> averaging over a few
> runs)
> 
> I use one thread per StatefulKnowledgeSession... My machine
> has 2 cores, but
> it will eventually be running on an 8 core beast, so i
> reckon this was a
> good improvement.  I was just worried that I wouldn't
> be able to
> simultaneously process multiple K-Sessions, but apparently,
> Drools doesn't
> mind.  I'm pretty sure any machine with multiple cores
> supports parallel
> java threads, no? 
> 
> 
> 
> -----
> Regarding my Utilities method, eg. 
> isWithinTimePeriod("20100308",
> "20090405", 1, "Y")
> 
> I can get about 5ms off by commenting out the eval, so it's
> not going to be
> a big jump even if I fix it, but, well, I am using yyyyMMdd
> Strings, which
> in the method, I sub-stringed, converted to ints,
> instantiated DateMidnight
> objects, and compared using Joda-time
> daysBetween/monthsBetween/yearsBetween
> methods.  
> 
> My thought was that pre-converting to ints would help, so
> that each
> ClaimLine has year/month/day int variables, and pass them
> in instead. (i.e.,
> Saves 3 String.substring()'s, and 3
> Integer.parseInt()).  but that actually
> slowed it down a few milliseconds. (Maybe passing 6 params
> instead of 2?!)
> 
> I'm comparing two dates by an arbitrary period, like "2
> days" or "1 month",
> and need the framework of the Gregorian Calendar.  So,
> I don't think I can
> do anything about this.  2 months is never guaranteed
> to be a set number of
> milliseconds.  It all depends on the claim date, which
> is fact data, and
> therefore variable.
> 
> Regards,
> Daniel
> 
> -- 
> View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Parallelization-tp809341p809753.html
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> Nabble.com.
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