Good day.

	I've been using POV-Ray for about three years but have not produced any
results of interest.  I have recently taken a fresh interest and am now
enjoying the animation features as well as the new processor technology
that simply wasn't feasible three years ago.  I am a Sun user who has
access to multi-cpu systems with UltraSparc architecture and I was
curious to see what difference there would be between a reasonable Intel
based system and a Sun UltraSparc workstation.  I was surprised to find
that the SUNOS version of POV-Ray was sadly lacking in performance.  I'm
wondering if there are others out there who would participate in
creating an optimized version of POV-Ray that would execute as a
multi-threaded application within the new Solaris 7 environment?


  details about why I want to do this ... 
http://www.interlog.com/~dclarke/povray/povray.html

Dennis Clarke

dcl### [at] interlogcom

http://www.interlog.com/~dclarke

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I'm getting access to a Sun box, so the SunOS POV-Ray should be updated
from 3.02 in the near future.  Hard to tell at this point what the
performance will be like, but it's not going to be any more threaded
than any of the other versions (i.e. not at all).  It's my feeling that
it's not practical (without major rewrite, increase in burden of
maintenance) to add support for threading to the official POV-Ray at
this point, due largely to the need to keep the rendering engine
portable across so many platforms.

As for Dennis' efforts to support a threaded POV-Ray: be my guest.  If
it will require changes to files outside the unix directory in the
source tree, it probably can't be incorporated into an official version,
but I have no problems with platform-specific enhancements that boost
performance on some platforms (e.g. PVMPOV) as long as they abide by the
license.  In theory, ray tracing should thread wonderfully, and users of
SMP machines could see a great deal of benefit.

-- 
Mark Gordon
mtg### [at] povrayorg

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Dennis Clarke <dcl### [at] interlogcom> wrote:
 
  > I was surprised to find that the SUNOS version of POV-Ray was sadly
  > lacking in performance.

why were you surprised? are other applications not lacking in performance?

I find that my dinky, el-cheapo dual PPro outruns the 270Mhz UltraSparc-IIs
at the university by much more than the second CPU would account for. the
Sun keyboards are _very_ good (almost as good as the old PS/2 keyboard I
saved from the dumpster), but I'm decidedly underimpressed by what I've seen
of the rest of their hardware, and puzzled by how much people are still
willing to pay for that hardware.

you could try if UltraLinux speeds things up a bit, I hear it does for most
things. and use egcs to compile, it may help. but the bottom line remains as
you noted, a pentium-2 with a plain-vanilla povray will beat that $25k
workstation. if you multithread povray (which is going to be a *huge* task
btw), a dual pentium-2 with that version will probably still outrun that
Ultra.

Lodewijk
(if someone can enlighten me about the big deal with Sun hardware, gladly.
it's been puzzling me for a long time now)

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Thanks for the fast reply.  

I've started to think about what would be needed to create a
multi-threaded client-server version of POV-Ray.  I've made a few phone
calls and talked it over with some friends who believe that number
crunching is a valid past-time.  Response has been good.  I'll have
access to a Sun Ultra Enterprise E450 server for some of this but will
probably use a Sun Ultra 2300 and a SparcStation 20 longterm.  I am
wondering how this project should shape up and will draw up a timeline,
a budget, a team and some initial thoughts about the deliverables.  The
first stage will be discovery and that entails the source code as it
stands today.  Once a few people are intimate with the source and its
issues, the next stage would be to see if its possible to build a
client-server application shell around it that farms out image component
responsibilites to clients.  While a client-server wrapper is a bit of a
hack it is a reasonable starting point.  A full rewrite of the code
would be a very daunting task but the time has come, I unilaterally
think, to either take this application to the next level or to forever
leave it as a single-threaded single machine application.  I have no
intent on being a criticizer of what POV-Ray is today, I stand and
salute the authors for an excellent product.  I merely think that some
form of investigation into a viable client-server multi-threaded edition
may be prudent at this time.

Dennis Clarke
http://www.interlog.com/~dclarke/povray/povray.html

ps: I see no need to keep POV-Ray portable across "so many platforms". 
It may be wise to drop support on those systems that do not support
multi-threaded operating systems.  Merely a thought.

------------------------------------------------------------------------

Mark Gordon wrote:
> 
> I'm getting access to a Sun box, so the SunOS POV-Ray should be updated
> from 3.02 in the near future.  Hard to tell at this point what the
> performance will be like, but it's not going to be any more threaded
> than any of the other versions (i.e. not at all).  It's my feeling that
> it's not practical (without major rewrite, increase in burden of
> maintenance) to add support for threading to the official POV-Ray at
> this point, due largely to the need to keep the rendering engine
> portable across so many platforms.
> 
> As for Dennis' efforts to support a threaded POV-Ray: be my guest.  If
> it will require changes to files outside the unix directory in the
> source tree, it probably can't be incorporated into an official version,
> but I have no problems with platform-specific enhancements that boost
> performance on some platforms (e.g. PVMPOV) as long as they abide by the
> license.  In theory, ray tracing should thread wonderfully, and users of
> SMP machines could see a great deal of benefit.
> 
> --
> Mark Gordon
> mtg### [at] povrayorg

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In article <37365B9C.6D5A47A7@interlog.com>, Dennis Clarke wrote:

  > I merely think that some form of investigation into a viable
  > client-server multi-threaded edition may be prudent at this time.
  
http://www.geocities.com/CapeCanaveral/Lab/6386/pvmpov/index.html

I don't know if that's the original site, but that does what you want,
albeit perhaps not the way you want. this is the same version one would
install on a pile-of-pc's running Beowulf on Linux.

  > ps: I see no need to keep POV-Ray portable across "so many platforms". 
  > It may be wise to drop support on those systems that do not support
  > multi-threaded operating systems.  Merely a thought.

why are you so bent on multithreading? if your intention is to make povray
run faster, and I assume you will want to render multiple frames, why not
just start multiple instances of povray? that's what I do on my dual PPro, I
have a small perl hack that I use when I want to run an animation and it
keeps both my CPUs quite busy. I know there's also a job scheduler from GNU
somewhere, you just submit jobs and it starts them when the load is right.

with some hacking one could even write a script and a little tool to split
one scene in a given number, distribute the parts to different processes
(not threads) and combine the results.

multithreading povray is going to be a *huge* task with, AFAICS, little
advantage to it.

Lodewijk

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