Hi Daniel,

I was reading the other day that a JVM implementation does not necessarily have to run Java threads in different Processes (taking advantage of multiple cores).  If you saw a significant speedup then I would assume your JVM does this.  It is worth investigating for your production deployment.  I would think that recent JVMs on modern operating systems would support this, but I also wouldn't leave it up to chance.

This post seems to imply that the only JVM/OS combinations that don't support native threads are Java 1.2 or Solaris: http://forums.sun.com/thread.jspa?threadID=5330507

About StatefulKnowledgeSessions: You should be able to run these in parallel no problem.

-Steve

rules-users-bounces@lists.jboss.org wrote on 05/11/2010 07:55:18 AM:

> From:
>
> djb <dbrownell83@hotmail.com>
>
> To:
>
> rules-users@lists.jboss.org
>
> Date:
>
> 05/11/2010 08:01 AM
>
> Subject:
>
> Re: [rules-users] Parallelization
>
> Sent by:
>
> rules-users-bounces@lists.jboss.org
>
>
> 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
>
> --
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