[ODE] Performance question

[STenyaK (Bruno Gonzalez)]

On Fri, 15 Sep 2006 02:52:23 +0200, Jon Watte (ODE)  
<hplus-ode at mindcontrol.org> wrote:

> Is this in release mode or debug mode?
Debug mode.
> Are you using floats or doubles?
Doubles
> How big is your step size?
Doesn't matter for this problem (the problem happens indepndently of step  
size), but i'm currently running physics at 300Hz.
> Do you empty your contact joint group every step? (doesn't hurt to ask)
Yes
> On what kind of client hardware?
Amd Sempron 2Ghz + 512kb L2, 512megs of ram (no swapping is needed at any  
time during simulation), on a gentoo linux 2.6.16 or so. No other apps are  
taking the cpu. It's been reported to also happen in windowsXP + msvc, and  
to also be solved by replacing all suspension physics with hinge2 joints.
> If you run a profiler on the program while it's getting 1-4 fps, where  
> does it say you're spending your time?
Running a profiler takes too much cpu time (simulation can't run realtime,  
so graphics are not rendered anymore, and there are more side effects), so  
i profile the important parts myself, using SDL timers (which give a  
precission of msecs). The slowdown is definitely due to ODE (which takes  
up to 95% of total app time, but usually 40-50%), but the timing is too  
little precise to know if the problem is collision detection or the solver  
(i get an average of 50% time of the sum spent on each of them, so i dunno  
what to think about it).


-- 
Saludos,
     STenyaK

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