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Re: [Manta] Image degrades as more processors get involved!


Chronological Thread 
  • From: Solomon Boulos <boulos@cs.utah.edu>
  • To: "Christian Odom" <cnsodom@gmail.com>
  • Cc: "Dirk Reiners" <dirk@infiscape.com>, manta@sci.utah.edu
  • Subject: Re: [Manta] Image degrades as more processors get involved!
  • Date: Wed, 5 Sep 2007 17:36:18 -0600
Hi Dirk and Christian,

The change camera stuff looks good. As you mentioned (Dirk), using Manta's transaction interface does correctly handle the thread-safety for the Camera (the transactions are only called after rendering has completed for that frame).

Try running Manta with SSE disabled on your amd64 box by turning SSE off in the cmake settings (I believe you did this for the ia64 run as well).

Does the same problem occur for bin/manta with your camera? Your scene setup seems slightly different (is it just a hard coded color change in StandAlone/manta.cc or is it something more?) so I'd like to rule that out as a possible problem.

Solomon

On Sep 5, 2007, at 4:15 PM, Christian Odom wrote:



On 9/5/07, Dirk Reiners <dirk@infiscape.com> wrote:
        Hi Christian,

Christian Odom wrote:
>
>
> On 9/5/07, *Solomon Boulos* <boulos@cs.utah.edu
> <mailto: boulos@cs.utah.edu>> wrote:
>
> Do you run into the problem with -np 1? Also, would it be possible
> to get the full copy of your camera implementation instead of just
>     makeRays (which looks okay to me).
>
>
> I am having to forward the X session over the net so it is really slow,
> but from what I can tell the image looks fine with -np 1.
>
> I have attached the current MatrixCamera class. I really need to go
> through and clean it up. Please excuse the mess.

Could you also post the piece of the NetworkUI that sets up the Camera?
I'm a little worried that there might be something in there that's not
threadsafe. We have worked under the assumption that Manta takes care of
thread-safety for the Camera, but I'm not totally sure.

Certainly.

I have also included a picture of the output when manta is running on my laptop with only one processor. Its an amd64. There seems to be a little noise in the image. A little on the sphere and a little on the bottom left of the plane. When there are multiple processors the "noise" moves around the image. This is not the case with only one processor.

        Dirk



--
Christian Odom
Graduate Student
Center for Advanced Computer Studies
http://www.cacs.louisiana.edu
Louisiana Immersive Technologies Enterprise
http://www.lite3d.com
<NetworkUI.cc>
<NetworkUI.h>
<Screenshot.png>




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