It looks like it was an Apple java bug: I just did another upgrade to  
an even more "latest" java release and the problem went away.

Was definitely not GC, I'd checked for that; and things ran great when  
using 3D libraries, go figure.  Looks like it was a bug in Apple's  
graphics queue.

Thanks anyway!

Sean

On Feb 10, 2010, at 2:49 PM, Miles Parker wrote:

> I haven't seen these in my own non-MASON API code using SWT. (That's  
> not intended as a snarky comment, just an extra data point. :D). But  
> I don't actually think it's AWT because I just ran some (pretty  
> simple) Ascape code to see and I asn't seeing this either. Are these  
> particularly large models? When you say 2D I assume you mean that  
> there aren't any 3@ libs involved.. I'm using latest VM under Snow  
> Leopard running under pure 64 bit mode. Two thoughts that probably  
> have already occurred to you..
>
> 1. This sounds like classic GC hyperactivity. Have you taken a look  
> with YourKit and/or futzed with heap and permgen? If you tweak the  
> gc you should at least be able to see if the policy affects the  
> behavior. Do you have a lot of weak references or anything like that?
> 2. I've forgotten what the other one was.. :) Oh yeah, 3D libs but  
> again it doesn't sound like you're using those.
>
> Miles
>
> On Feb 10, 2010, at 8:21 AM, Sean Luke wrote:
>
>> I've noticed that when running under the latest version of Java on  
>> OS X, simulations will run fine under 2D visualization, then  
>> suddenly drop to half their speed for a few seconds, then jump up  
>> to full speed again, and back down, and so on.  I'm trying to nail  
>> down what might be the problem.  I regressed to very early versions  
>> of MASON and they're all having the problem so I suspect it may be  
>> something tickled by Apple.  However I can't reproduce it with  
>> simple animation tests outside of MASON.  Has anyone else seen this?
>>
>> Sean