In article <90m3ou8uubbqfdu6m3ailgpg7n4gtss85u@4ax.com> , ABX 
<abx### [at] abxartpl>  wrote:

> On Fri, 13 Sep 2002 22:10:49 +1000, "Chris Cason"
> <new### [at] deletethispovrayorg> wrote:
>> > Since there are some press informations about HyperThreading are there also
>> > some news about optimizations made for POV ?
>>
>> No, I know nothing specific.
>
> I have wrote to Francois Piednoel when he asked that one place where threading
> could be applied is spline interpolation. Every dimension can be calculated
> parallel becouse not influence each other. That's only idea. I can't imagine
> how it could be written in the sources to point compiler it should be compiled
> with threading.

Actually, you remind me of something:

While we all usually think more or less of POV-Ray as being hard to modify
for multithreading, this is not really so for one big part of the code.  The
intersection tests (and bounding) are with a very few exceptions next to
independent of global variables and very well isolated within the code
already.  So one could restrict threading to intersection tests and keep
multiple intersection stacks.  Hand the data over to a thread doing the
texturing after all intersections for one pixel have been calculated.  This
would still allow things like radiosity to work as they should assuming only
one thread calculates textures.  Only finishes (and maybe media) would have
to be taken into account in the other threads.  While balancing the load
would be more difficult and depend a lot on the scene, it should be "easy"
to implement in the current codebase and yield reasonable results with two
or maybe even four threads.  Of course on real supercomputers it would be
next to useless, but on common desktop multiprocessor systems...

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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