Stefan Viljoen <spamnot@<removethis>polard.com> wrote:

>
> Hi Kenneth
>
> For a detailed explanation, take a look at the image I submitted to Paul
> Bourke at Swinburne univ, which was rendered on a "farm" of Alpha CPU based
> systems, and the article he wrote about it:
>
> http://astronomy.swin.edu.au/~pbourke/raytracing/parallel/
>
> Basically, you use PovRay INI file statemens to restrict a certain instance
> of PovRay to only rendering a part of the scene. With any multi-core or
> multi-processor system you can make this as complicated as you want, I just
> usually use horisontal segments, for simplicity. The idea is like any
> co-operative effort - one core / CPU does one part of the image, another
> does the next, etc. If one finishes before the other, the work assigned to
> the remaining CPUs is redivided, and the "free" CPU again gets part of the
> remaining work.
>

Thanks, Stefan, that's a very lucid, understandable description of the
process.

All three of my current POV-loaded computers use single-core processors, so
this whole idea of dual-core processing (and multi-processor rendering) is
new to me.  I DO see it's advantages!! I'll have to do a bit of research to
fully understand the process.

From all that I've read here, so I understand that POV v3.7 will
simultaneously allow multi-core rendering of an image, in chunks, AND
combine those separate segments into the final image without having to use
some third-party software to do so?

Ken

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Kenneth spake:


> From all that I've read here, so I understand that POV v3.7 will
> simultaneously allow multi-core rendering of an image, in chunks, AND
> combine those separate segments into the final image without having to use
> some third-party software to do so?

I don't know. Warp will probably be able to correct me here, but I'm
guessing that you'll need a "SMP capable" operating system as well. As far
as I'm aware you'll need an SMP version of XP / Vista in order to get SMP
capabilities in the POV 3.7 running on that system. Same with Linux -
you'll need to run an SMP kernel to be able to run POV 3.7 in SMP mode.

For example, my dual-core Linux system runs a non-SMP kernel during office
hours (because I can't get my Linux Nvidia graphics drivers to work in the
SMP kernel). During the night it runs the Linux SMP kernel (2.6.14.3) in
SMP mode, which means I can render dual-core, but the system stands there
in text-only (80x25) mode while rendering.

IMHO this factor (i. e. the underlying operating system) will need to be
considered when wanting to use the SMP facilities available in 3.7...

This of course does not limit the utility or "coolness" value of having
"auto-SMP" in POV v3.7...

Warp?
-- 
Stefan Viljoen
Software Support Technician / Programmer
Polar Design Solutions

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Stefan Viljoen <spamnot@ <removethis>polard.com> wrote:
> I don't know. Warp will probably be able to correct me here, but I'm
> guessing that you'll need a "SMP capable" operating system as well. As far
> as I'm aware you'll need an SMP version of XP / Vista in order to get SMP
> capabilities in the POV 3.7 running on that system. Same with Linux -
> you'll need to run an SMP kernel to be able to run POV 3.7 in SMP mode.

  If you don't know, then don't spread dubious information, please.

  There's no "SMP version of XP". All XPs are capable of using multiple
processors.

  As for linux, most distros will automatically use multiple processors
when you install linux.

  There isn't a separate "SMP mode" in pov3.7. It just detects how many
processors you have (either physical or virtual) and runs twice as many
threads. In a way you could say that it's "always" in "SMP mode"; it just
selects the number of threads according to the number of processors
(if I'm not mistaken, always at least two threads unless specifically
one is specified).

> IMHO this factor (i. e. the underlying operating system) will need to be
> considered when wanting to use the SMP facilities available in 3.7...

> This of course does not limit the utility or "coolness" value of having
> "auto-SMP" in POV v3.7...

  It wouldn't make much sense to run an OS which does not support
multiple processors in a system with multiple processors. I don't
think there's even anything "to be considered" here.

-- 
                                                          - Warp

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Warp spake:

> Stefan Viljoen <spamnot@ <removethis>polard.com> wrote:
>> I don't know. Warp will probably be able to correct me here, but I'm
>> guessing that you'll need a "SMP capable" operating system as well. As
>> far as I'm aware you'll need an SMP version of XP / Vista in order to get
>> SMP capabilities in the POV 3.7 running on that system. Same with Linux -
>> you'll need to run an SMP kernel to be able to run POV 3.7 in SMP mode.
> 
>   If you don't know, then don't spread dubious information, please.

Yikes! No offence - next time I'll just shut up then, instead of given ANY
information. I did mean to spread dubious information - what's dubious
about saying "I guess you'll need an SMP capable operating system?" Please?

Really, if you don't volunteer something, until you're "sure" what the
heck's the point of discussion? Nobody would ever say a word about...
anything..!
 
>   There's no "SMP version of XP". All XPs are capable of using multiple
> processors.

So I stand corrected. I did say "I don't know". You have corrected me - so
what?

>> IMHO this factor (i. e. the underlying operating system) will need to be
>> considered when wanting to use the SMP facilities available in 3.7...
> 
>> This of course does not limit the utility or "coolness" value of having
>> "auto-SMP" in POV v3.7...
> 
>   It wouldn't make much sense to run an OS which does not support
> multiple processors in a system with multiple processors. I don't
> think there's even anything "to be considered" here.

Again, you seem VERY touchy about my why of phrasing things. If I offend
you, I apologise. What I was referring to is the fact that (maybe due to me
simply being stupid / inexperienced / inadquate) I cannot get the binary
Nvidia driver to work in my SMP kernel - which means I must "consider" (as
may any other user in the same situation) WHICH kernel to run when
raytracing, and factor this into my workflow etc.

And did the original poster not say that he now has a better idea of what is
going on?

Nobody knows absolutely EVERYTHING all the time, except you, it seems, and
you seem to have a problem with people who are not already at your very
high levels of experience and omnipotence as regards raytracing and
computers in general.

Really - this is an open forum. No need to snipe.

Regards,
-- 
Stefan Viljoen
Software Support Technician / Programmer
Polar Design Solutions

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