I have a dual pentium II system running windows NT 4.0
However, I have seen no speed improvement from the second processor.
I thought Povray was a multi-threaded application??

Post a reply to this message

Phil Brewer wrote:
> 
> I have a dual pentium II system running windows NT 4.0
> However, I have seen no speed improvement from the second processor.
> I thought Povray was a multi-threaded application??

It is not written to take advantage of a second precessor. You can run multiple
instances of pov or take a look at one of the custom compiles like PVM Pov.
See my links for unnofficial versions.

-- 
Ken Tyler

See my 850+ Povray and 3D Rendering and Raytracing Links at:
http://home.pacbell.net/tylereng/index.html

Post a reply to this message

Phil Brewer <prb### [at] mtuedu> wrote:
: I thought Povray was a multi-threaded application??

  What made you think that?

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

Post a reply to this message

Nieminen Juha wrote:
> 
> Phil Brewer <prb### [at] mtuedu> wrote:
> : I thought Povray was a multi-threaded application??
> 
>   What made you think that?

See ! I told you this was a vfaq candidate :) I would write the reply but
I just don't know enough about it to be authoritative and would likely do
a poor job of it.

Anyone else want to give it a try ?

-- 
Ken Tyler

See my 850+ Povray and 3D Rendering and Raytracing Links at:
http://home.pacbell.net/tylereng/index.html

Post a reply to this message

Perhaps that since it is such a great program one could only expect it to be
multithread-able. At least, that is what I would expect.

--
Anthony L. Bennett
http://welcome.to/TonyB

Non nova, sed nove.

Post a reply to this message

TonyB wrote:
> 
> Perhaps that since it is such a great program one could only expect it to be
> multithread-able. At least, that is what I would expect.
> 
> --
> Anthony L. Bennett
> http://welcome.to/TonyB
> 
> Non nova, sed nove.

As I understand it this is not entirely trivial to add support for and
since it is pretty much a platform specific function portability becomes
an issue.

-- 
Ken Tyler

See my 850+ Povray and 3D Rendering and Raytracing Links at:
http://home.pacbell.net/tylereng/index.html

Post a reply to this message

Ken <tyl### [at] pacbellnet> wrote in message
news:37CF8EE8.892E1377@pacbell.net...
> Anyone else want to give it a try ?


I use two CPUs and have some experience, so I'll give it a shot if you're
interested.

--John

Post a reply to this message

"John M. Dlugosz" wrote:
> 
> Ken <tyl### [at] pacbellnet> wrote in message
> news:37CF8EE8.892E1377@pacbell.net...
> > Anyone else want to give it a try ?
> 
> I use two CPUs and have some experience, so I'll give it a shot if you're
> interested.
> 
> --John

  If you have ever visited Warps VFAQ you will know that a few of us have
banded together to offer concise explanations to the most frequently asked
questions in the news groups. I have offered answers as well as others
and these have been included in it's content. It saves us from answering
the same questions over and over again by simply responding with a link
to Warp's site.
  If you think that you can write a fairly comprehensive answer to the
question feel free to answer it here and Warp will add if when he gets
time.

To see the VFAQ go to: http://www.students.tut.fi/~warp/povVFAQ.html

Thanks for the interest John,

-- 
Ken Tyler

See my 850+ Povray and 3D Rendering and Raytracing Links at:
http://home.pacbell.net/tylereng/index.html

Post a reply to this message

Phil Brewer wrote in message <37cf222f@news.povray.org>...
>I have a dual pentium II system running windows NT 4.0
>However, I have seen no speed improvement from the second processor.
>I thought Povray was a multi-threaded application??


POV-Ray for Windows is.  One thread is used for rendering, and there is one
thread for each CodeMax editing session.  As a result, you get a very slight
performance boost from the second CPU if you are rendering a scene and
editing another at the same time.  I suspect that the increase is on the
order of a tenth of a percent or so.

Mark

Post a reply to this message

Ken <tyl### [at] pacbellnet> wrote in message
news:37D181A1.FCA77AA4@pacbell.net...
>
>
> "John M. Dlugosz" wrote:
> >
> > Ken <tyl### [at] pacbellnet> wrote in message
> > news:37CF8EE8.892E1377@pacbell.net...
> > > Anyone else want to give it a try ?
> >
> > I use two CPUs and have some experience, so I'll give it a shot if
you're
> > interested.
> >
> > --John

On the use of POV-Ray for Win32 with multiple CPU's

The POV-Ray rendering engine is a single thread of execution, so when I run
it on my dual Pentium Pro (running NT4) the CPU indicator only goes up to
about 50%.  POV doesn't use more than half the available power on the
machine.

That's the basic issue, though to quibble a bit it's not exactly true:  the
rendering engine soaks up one whole CPU, but the editor runs on its own
thread, and operating system functions (writing to the file, updating the
display, network activity, system background tasks) run on different
threads.  This gives a little bit of a bonus, and the system uses as much as
54% of available MIPS when I watch it.  More importantly, the machine is
still highly responsive, and editing or other applications continue on
without being sluggish.

But for a long render, it's annoying to have one CPU be mostly idle.  What
can be done to cut rendering time in half (from 20 hours down to 10, for
example)?

The simplest thing is to run two copies of POV on the machine.  Have one
copy render the top half, and the other render the bottom half.  Then paste
the halves together in your picture editor.

One thing to watch out for:  don't just fire up two copies and point them at
the same INI file and image file.  They will overwrite each other's output
and make a big mess.  Instead, you must make sure each is writing to a
different file.

For moderate renders, I'll let one copy chug away on the long render, and
use a second copy interactivly to continue development in POV.

--John

Post a reply to this message