[rules-users] Drools 4 poor performance scaling?

Mark Proctor mproctor at codehaus.org
Mon Jun 30 12:39:13 EDT 2008


Fenderbosch, Eric wrote:
> We are having a similar problem, although our fact count is much higher.
> Performance seems pretty good and consistent until about 400k facts,
> then performance degrades significantly.  Part of the degradation is
> from bigger and more frequent GCs, but not all of it.
>   
If you have multi-cpu there is a JVM command you can set a dedicated cpu 
for GC, that helps somewhat.
> Time to load first 100k facts: ~1 min
> Time to load next 100k facts: ~1 min
> Time to load next 100k facts: ~2 min
> Time to load next 100k facts: ~4 min
>
> This trend continues, going from 600k to 700k facts takes over 7
> minutes.  We're running 4.0.7 on a 4 CPU box with 12 GB, 64 bit RH Linux
> and 64 bit JRockit 5.  We've allocated a 9 GB heap for the VM using
> large pages, so no memory paging is happening.  JRockit is started w/
> the -XXagressive parameter, which enables large pages and the more
> efficient hash function in HashMap which was introduced in Java5 update
> 8.
>   
Other than the CPU thing, Drools won't take advantage of multipe cpus at 
the moment.
> http://e-docs.bea.com/jrockit/jrdocs/refman/optionXX.html
>
> The end state is over 700k facts, with the possibility of nearly 1M
> facts in production.  After end state is reached and we issue a few GC
> requests, if looks like our memory per fact is almost 9k, which seems
> quite high as most of the facts are very simple.  Could that be due to
> our liberal use of insertLogical and TMS?
>   
It could be related to this, especially if you create a long chain of 
logical relationships.
> We've tried performing a "commit" every few hundred fact insertions by
> issuing a fireAllRules periodically, and that seems to have helped
> marginally.
>
> I tried disabling shadow proxies and a few of our ~390 test cases fail
> and one loops indefinitely.  I'm pretty sure we could fix those, but
> don't want to bother if this isn't a realistic solution.
>
> Any thoughts?
>   
Have you tried this on Drools 5.0? It 'doesn't need shadow proxies and 
implements a new Rete algorithm that is faster for retracts. You can get 
a nightly build from here, I'd be interested to find out how broken 5.0 
is :)
https://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/trunk/target/

We still have more performnace work to do, the items are known, just a 
matter of time, not all will make 5.0 though. but the main items include:
1) bytecode compiled Rete network, instead of interpreted nodes. I'm 
hoping this will have a large impact, reducing GC and general 
indirection and recursive method call frames.
2) "true modify", instead of a retract+assert, will also remove the need 
for activation normalistaion that we do for TMS and the agenda event model.
3) range indexing (initially literals, but would like to explore 
variables too).

Steve, before he left fedex, was creating a simulator for this use case, 
but removing anything business sensitive. So that we could use it 
publicly as a benchmark and to help us tune the engine. Are you still 
working on this? Steve use to chat to us on irc, can I ask you to pop on 
for a chat?
http://labs.jboss.org/drools/irc.html

mark
> Thanks
>
> Eric
>
> -----Original Message-----
> From: rules-users-bounces at lists.jboss.org
> [mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Ron Kneusel
> Sent: Thursday, June 26, 2008 12:47 PM
> To: rules-users at lists.jboss.org
> Subject: [rules-users] Drools 4 poor performance scaling?
>
>
> I am testing Drools 4 for our application and while sequential mode is
> very fast I get very poor scaling when I increase the number of facts
> for stateful or stateless sessions.  I want to make sure I'm not doing
> something foolish before deciding on whether or not to use Drools
> because from what I am reading online it should be fast with the number
> of facts I have.
>
> The scenario:  I have 1000 rules in a DRL file.  They are all of the
> form:
>
> rule rule0000
>     when 
>         Data(type == 0, value> 0.185264);
>         Data(type == 3, value < 0.198202);
>     then 
>         insert(new AlarmRaised(0));
>         warnings.setAlarm(0, true);
> end
>
> where the ranges checked on the values and the types are randomly
> generated.  Then, I create a Stateful session and run in a loop timing
> how long it takes the engine to fire all rules as the number of inserted
> facts increases:
>
>         //  Run 
>         for(j=0; j < 100; j+=5) {
>
>             if (j==0) {
>                 nfacts = 1;
>             } else {
>                 nfacts = j;
>             }
>
>             System.out.println(nfacts + ":");
>
>             //  Get a working memory
>             StatefulSession wm = ruleBase.newStatefulSession();
>
>             //  Global - output
>             warnings = new Alarm();
>             wm.setGlobal("warnings", warnings);
>
>             //  Add facts
>             st = (new Date()).getTime();
>             for(i=0; i < nfacts; i++) {
>                 wm.insert(new Data(rand.nextInt(4),
> rand.nextDouble()-0.5));
>             }
>             en = (new Date()).getTime();
>             System.out.println("    facts = " + (en-st));
>
>             //  Now run the rules
>             st = (new Date()).getTime();
>             wm.fireAllRules();
>             en = (new Date()).getTime();
>             System.out.println("    rules = " + (en-st));
>
>             //  Clean up
>             wm.dispose();
>
>             System.out.println("\n");
>         }
>
> This code is based on the HelloWorldExample.java code from the manual
> and the setup for the rule base is the same as in the manual.  As the
> number of facts increases runtime increases dramatically:
>
> facts -- runtime (ms)
> 10 -- 168
> 20 -- 166
> 30 -- 344
> 40 -- 587
> 50 -- 1215
> 60 -- 1931
> 70 -- 2262
> 80 -- 3000
> 90 -- 4754
>
> with a maximum memory use of about 428 MB RAM.  By contrast, if I use
> sequential stateless sessions, everything runs in about 1-5 ms.
>
> Is there something in my set up that would cause this, or is this how
> one would expect Drools to scale?  I read about people using thousands
> of facts so I suspect I'm setting something up incorrectly.
>
> Any help appreciated!
>
> Ron
>
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