Hello.  I'm a new Povray user and using version 3.6 on Windows XPpro.

No matter what I set the process priority at, the CPU usage stays at 25%
with perhaps the very occasional peak of 26%.

Question is, how do I instruct Povray to hog all the CPU resources?

It almost seems like Povray is being throttled someway...

This is a dual Xeon (3.2ghz) system and I want to see what it can do!!
<grin>

Thanks for any advice.
Joe

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> This is a dual Xeon (3.2ghz) system and I want to see what it can do!!

POV-Ray doesn't make use of multiple processors. Sorry!

Since you said 25%, I'm going to assume that those processors have
hyperthreading. That means Windows essentially thinks you have four
processors, and POV-Ray can only use one, so it says it's using 25%.

In reality, it's a lot closer to 50% of the real processing power that you
have. I have a single hyperthreading processor, and POV-Ray always says it's
using 50%. This is equivalent to 100% of what a non-hyperthreading processor
could do; it just pretends that a hypertheading processor can do twice the
work. In reality, it can't, because if another thread comes along and tries
to run, it's going to slow the first one down (because they're sharing the
same processor). So the percentages are lying, in a sense. 50% for me means
a lot closer to 100%, and 25% for you means a lot closer to 50%.

You can't get higher than that though because POV-Ray runs in a single
thread. I think there are patched versions, though, which make use of
multiple threads, and you can get better performance...

 - Slime
 [ http://www.slimeland.com/ ]

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Aha!!!  Well, that explains it pretty plainly!  Haha.  Thanks for letting me
know that.

I did think that the 25% max utilization on a four logical processor system
did seem a bit too "math friendly" explainable!

I'll try and find a "patched" version like you suggested.  It would be
interesting to see it run full-boar.

Thanks Slime!
Joe


"Slime" <fak### [at] emailaddress> wrote:
> > This is a dual Xeon (3.2ghz) system and I want to see what it can do!!
>
> POV-Ray doesn't make use of multiple processors. Sorry!
>
> Since you said 25%, I'm going to assume that those processors have
> hyperthreading. That means Windows essentially thinks you have four
> processors, and POV-Ray can only use one, so it says it's using 25%.
>
> In reality, it's a lot closer to 50% of the real processing power that you
> have. I have a single hyperthreading processor, and POV-Ray always says it's
> using 50%. This is equivalent to 100% of what a non-hyperthreading processor
> could do; it just pretends that a hypertheading processor can do twice the
> work. In reality, it can't, because if another thread comes along and tries
> to run, it's going to slow the first one down (because they're sharing the
> same processor). So the percentages are lying, in a sense. 50% for me means
> a lot closer to 100%, and 25% for you means a lot closer to 50%.
>
> You can't get higher than that though because POV-Ray runs in a single
> thread. I think there are patched versions, though, which make use of
> multiple threads, and you can get better performance...
>
>  - Slime
>  [ http://www.slimeland.com/ ]

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"jdgonko" <jdg### [at] comcastnet> wrote in
news:web.423fc890a184b2cbb86d3b2b0@news.povray.org: 
> 
> "Slime" <fak### [at] emailaddress> wrote:
>> > This is a dual Xeon (3.2ghz) system and I want to see what it can
>> > do!! 
>>
>> POV-Ray doesn't make use of multiple processors. Sorry!
>>
>> Since you said 25%, I'm going to assume that those processors have
>> hyperthreading. That means Windows essentially thinks you have four
>> processors, and POV-Ray can only use one, so it says it's using 25%.
>>
>> You can't get higher than that though because POV-Ray runs in a
>> single thread. I think there are patched versions, though, which make
>> use of multiple threads, and you can get better performance...
>>
>>  - Slime
>>  [ http://www.slimeland.com/ ]
> 

Another technique that usually works is to copy the scene file multiple 
times (e.g. 2, 4) with slightly different names (e.g. scene.pov becomes 
scene1.pov and scene2.pov).

Then, open two instances of POV-Ray (you'll need to disable the keep 
single instance option in the GUI).  Set one to render one file, and set 
the other to render the other, but use commandline or INI options to get 
them to render only part, e.g. 50% of the file (e.g. top half, bottom 
half).  Set the instances to use different processors (I believe you only 
have fine tuning on this in XP Pro; XP Home won't let you choose) and then 
wait for the renders to finish.  Finally, use a 2D Graphics Editor (e.g. 
MS Paint, the GIMP, Photoshop, etc) to put the two rendered halves 
together to get one whole image.  I believe that there were scripts to do 
this kind of thing on multiple computers over e.g. a network.  *shrugs*

I've always wondered, isn't there supposed to be a way to make two or four 
processors look like one really fast one to the computer?  I think that 
generally that kind of thing is usually hardware-based, but it might be 
useful in your situation, especially if you're trying to do an animation 
or render repeatedly.

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