OK, as was suggested, running multiple instances simultaneously to split the
work load is the way to go right now.  What I'd like to know (and it seems a
really silly question), is how to force POV-Ray to run two instances?

I have a rendering going along right now that's only at 5 PPS (what can I
say, the faster the computer, the more complex my scenes get!) and I'd like
to have it at 10 by running two instances with the affinity fixed to CPU0
for one and CPU1 for the second, however, when I try to run a second
instance, the focus just changes to the existing instance as though it's
designed not to allow multiple instances.

What am I doing wrong here... is there a command line switch to tell it to
force a second instance?  I had a look in the help files but I couldn't find
anything.

Regards,

Lance.

thezone.firewave.com.au
www.firewave.com.au

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On Thu, 18 Jul 2002 21:24:03 +1000, "Lance Birch" <-> wrote:
> is there a command line switch to tell it to
> force a second instance?

you mean Menu -> Options -> Keep Single Instance ?

in case of command line perhaps there could be a trick/workaround with
register changed via batch, but I never checked it

ABX

Post a reply to this message

> On Thu, 18 Jul 2002 21:24:03 +1000, "Lance Birch" <-> wrote:
> > is there a command line switch to tell it to
> > force a second instance?
>
> you mean Menu -> Options -> Keep Single Instance ?
>
> in case of command line perhaps there could be a trick/workaround with
> register changed via batch, but I never checked it

*slaps head*

I obviously didn't look hard enough in the help file (or in the menus for
that matter!).

Thanks ABX!

Lance.

thezone.firewave.com.au
www.firewave.com.au

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Whoops... better watch my radiosity when I do something like that eh... *he
says, looking at the two halves with their different radiosity solutions*

Are there any tips to get around this issue?  I know that there are save and
load abilities for radiosity, however does this only work for scenes that
have been fully rendered once?  I assume the large variation in the two
halves is because the samples of the opposite half aren't collected (because
no pre-trace for the opposite half is done).

Any suggestions?  Is it possible at all to split the scene up in this way
while using radiosity?

Should I be posting these in a different group (since it's not just with the
Windows version, obviously).

Lance.

thezone.firewave.com.au
www.firewave.com.au

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3d36c54f@news.povray.org...

> Any suggestions?  Is it possible at all to split the scene up in this way
> while using radiosity?

It really depends on your scene. High rad settings (count > 100, error_bound
< 0.5) usually make it possible to have split rendering with radiosity with
no impact on quality. All my rad scenes are done like this, sometimes with
parts rendering on different computers. In fact I'm obliged to do this
because of the large memory requirements.

With lower settings, it's hard to tell beforehand without trying on a
smaller version. Large expanses of rad-lit, colored surfaces such as walls
don't like it at all. More fuzzy scenes (grass, trees) are quite tolerant to
it, as are skies with ambient 1.

G.

--

**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters

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Gilles Tran wrote:
<snip>
> smaller version. Large expanses of rad-lit, colored surfaces such as walls
> don't like it at all.

Those are unfortunately the ones I'm having the trouble with :/

Oh well, not to worry, although my radiosity settings are quite high (my
last small render took about 8 hours... which I suppose isn't too bad
really) I'll play around with them a bit and see if I can reduce the problem
by rendering some overlap as well.

I'm currently writing a small application to automatically split an image
across CPUs and computers...

Thanks for the tips!

Lance.

thezone.firewave.com.au
www.firewave.com.au

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"Lance Birch" <-> wrote in message news:3d36ed1c@news.povray.org...

<snip>

Hmm, what happens if you save the radiosity file, stop the render once it's
produced, and then share the file between two (or more) renders?

Post a reply to this message

Tom Melly wrote:
> "Lance Birch" <-> wrote in message news:3d36ed1c@news.povray.org...
>
> <snip>
>
> Hmm, what happens if you save the radiosity file, stop the render once
it's
> produced, and then share the file between two (or more) renders?

That's why I asked if it worked for only fully-completed renders.  I'm going
to test generating the pretrace and checking that it saves that, then
attempting a load with both... but I guess I'd have to set always_sample off
for them to end up the same?  I'm not sure, I'll have to try all these ideas
:/

Lance.

thezone.firewave.com.au
www.firewave.com.au

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Hey Lance,
    I've been thinking about doing the same kind of program... if you want
you can email me, I'd love to hear from you.

Thanks,
George Pantazopoulos



"Lance Birch" <-> wrote in message news:3d36ed1c@news.povray.org...
> Gilles Tran wrote:
> <snip>
> > smaller version. Large expanses of rad-lit, colored surfaces such as
walls
> > don't like it at all.
>
> Those are unfortunately the ones I'm having the trouble with :/
>
> Oh well, not to worry, although my radiosity settings are quite high (my
> last small render took about 8 hours... which I suppose isn't too bad
> really) I'll play around with them a bit and see if I can reduce the
problem
> by rendering some overlap as well.
>
> I'm currently writing a small application to automatically split an image
> across CPUs and computers...
>
> Thanks for the tips!
>
> Lance.
>
> thezone.firewave.com.au
> www.firewave.com.au
>
>

Post a reply to this message

Unfortunatly, 1 CPU + 1 CPU is not equal to 2 CPUs ... :)

When you have a 2 CPUs machine, the processors share the same front side
bus, and the same memory modules. A direct concequence is that 2 instances
running in the same time, will not share the same data set. The concequence
will be that you will double the memory traffic. This traffic is extremely
slow compare to the 2 or 3 GHz of the processors, and you will probably see
around 10% to 25% speed improvement with a seconds instance running
concurently, with 2 physical processors.

What you really want to do is the have 2 treads running using the same
"source data" in reading mode only (No L2 cache write combine between the 2
processors), both thread have their own local variables, and 2 differents
input.

The dream case, is to have a commun L2 cache, with 2 cores (or 2
Hyperthreading logical CPUs) and get the source data inside the L2 Cache (or
L3) and try to maximize the locality of the source data by rendering the
line n on the CPU n, and line n+1 on CPU(n+1) etc ...
Doing so, you will minimize the 1st L2 cache miss (statistically, 2 close
pixels share the same 3D collisions, at least the 1st one on the same
object).

I am testing those ideas on Xeon with Hyperthreading technology, and I am
seeing good performance improvement.

Of course, I did not test all the solutions, and an algorythm solution may
be better than the "brut force" solution I am offering.

I will be releasing a sample code doing so soon, based on PovRay 3.5

If you want to learn about Hyperthreading :
http://cedar.intel.com/media/training/hyper_threading_intro/tutorial/index.h
tm (Click on next at the bottom)
Cool training ;)


Francois

--------------------------------------------------------------
Francois Piednoel
Senior Performance Analyst
Pentium 4, Prescott, Tejas.
Intel Corporation




"Lance Birch" <-> wrote in message news:3d36a55f@news.povray.org...
> OK, as was suggested, running multiple instances simultaneously to split
the
> work load is the way to go right now.  What I'd like to know (and it seems
a
> really silly question), is how to force POV-Ray to run two instances?
>
> I have a rendering going along right now that's only at 5 PPS (what can I
> say, the faster the computer, the more complex my scenes get!) and I'd
like
> to have it at 10 by running two instances with the affinity fixed to CPU0
> for one and CPU1 for the second, however, when I try to run a second
> instance, the focus just changes to the existing instance as though it's
> designed not to allow multiple instances.
>
> What am I doing wrong here... is there a command line switch to tell it to
> force a second instance?  I had a look in the help files but I couldn't
find
> anything.
>
> Regards,
>
> Lance.
>
> thezone.firewave.com.au
> www.firewave.com.au
>
>

Post a reply to this message