[Radiance-general] Optimizing Radiance for cluster rendering

[Jack de Valpine]

Hi,

I think that binaries should be centrally located. It is not that big a 
problem to load over a network for this.

Likewise I think that scene files (octrees, etc) should be centrally 
located. It is just easier to manage.

I think a main problem is each process/node/core writing back image 
data. This can really slow things down on the nfs server if image pieces 
are being written back into one image. I think that it is better to have 
each process write out its output to its own file, which can be on the 
nfs server, and then assemble the pieces as a post process. Ambient 
cache data can still be shared and written to by multiple processes 
although I would recommend using one process to pre-populate the cache 
initially. And if as Andy mentions you are using something like 
rtcontrib then the shared ambient cache is a non-issue.

As far as compiler optimizations. While this could be nice, I think the 
real benefit is spreading things out over the cluster... that is 
hopefully where you get more opportunity to speed things up as opposed 
to some incremental increase due to compiler optimization.

-Jack

-- 
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction


On 4/16/2012 11:37 AM, Randolph M. Fritz wrote:
> On 2012-04-15 10:45:18 +0000, Iebele said:
>
>> Hi All,
>>
>> Nobody responded to the mail below yet. In the meanwhile I tried to 
>> build Radiance with Intels icc compiler. Binaries compiled with icc 
>> (many warnings) work for a simple scene, but fail when I render 
>> complex scenes (Segmentation fault). So I went back to gcc compiled 
>> binaries, but still I wonder if somebody can give me hints on what 
>> compiler to use, which flags, etc..
>
> There's some compiler interaction with the code which no-one has yet 
> dug into that makes icc compilation of Radiance fail for some 
> compilation settings.  For the moment, stick with gcc.
>
>> Concerning the binaries, I have a question alike: would it be better 
>> to make a local install of the binaries for each node?
>
> Depends on the cluster.  I suspect not much, though; the program 
> binaries are going to be cached in RAM in the nodes.
>