Re: how to make each channel's Cull & Draw locked to individual CPUs ------ SOS
Chris Ege (cege++at++amber.rec.ri.cmu.edu)
Mon, 30 Sep 1996 18:08:59 -0400
On Sep 27, 9:26am, Bernard Leclerc wrote:
> Subject: Re: how to make each channel's Cull & Draw locked to individual C
> flysiml++at++public.bta.net.cn wrote:
>
> With a single graphics pipe on your machine, I strongly recommend not to
> create multiple DRAW processes. Since you're using pf1.2 you won't be able
> to multithread the CULL stage as oppose to pf2.0
>
> If you've created multiple pfPipe's (one per channel), then your 3 DRAW
> processes will compete for a single resource (the graphics pipe) and force
> unnecessary graphics context switching.
>
> I don't recall Performer 1.2 API since I've been using 2.0 for more than a
> year now. However the principles are the same. With pf2.0 I would create a
> single pfPipe, open one pfPipeWindow and create 3 pfChannel's on it. If
> the CULL stage becomes the bottleneck, use pfMultithread.
>
> Remember, you have a single pipe, you want to run at 30 Hz (33 ms) and you
> have 3 channels. It turns out each channel can use up to 11 ms max. But I
> would budget only 8 ms since you need spare time.
>
> Now, would you obtain better performance with Performer 2.0? I don't think
> so. Pf2.0 hasn't increased performance over pf1.2 - it improved the API
> and added a lot of new functionalities. But performance wise, you can
> expect the same result.
>
> Good luck.
>
> --
> Bernard Leclerc CAE Electronics Ltd., 8585 Cote De
Liesse
> Technical Leader Saint-Laurent, Quebec, Canada, H4L-4X4
> 3-D Graphics Applications tel: +1 514 341 2000 extension 2275
> bleclerc++at++cae.ca fax: +1 514 340 5496
>-- End of excerpt from Bernard Leclerc
We are also working on a project that will use three displays. Your reply
worries us since we want 30fps. We are, however, going to be running it on an
Infinite Reality Engine. What type of RE are you running your application on
that gave you those performance results? If it isn't an IRE, would you expect
a problem getting 30fps with an IRE?
Thanks,
--
Chris Ege
SIMLAB, Robotics Engineering Consortium, Carnegie Mellon University
TEL: (412) 681-7125
send replies to cege++at++ux1.sp.cs.cmu.edu
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on Mon Aug 10 1998 - 17:53:39 PDT