Hi all,

    I've some very strange behavior in POV on my WinNT system. Recently I've
been doing a lot of animation work and during the test runs I'm rendering at
small frames (50 X 50 pixels). For my current scene each frame takes about 1
or 2 seconds to parse and render so I see them clicking by pretty quickly.
Every once in a while, though, the scenes fly by much faster, at about 3
frames per second (my guess).
    The problem is that I don't know if they are really rendering that
quickly or if the message buffer is just backed up or something like that. I
do know that there is no change in the scenes at that point (i.e., the scene
doesn't get occluded by 1 object and therefore make the render much
simpler). Also there is no predictability or reproducability of this
phenomena.
    My only though is that this. I've also noticed that in NT the POV
process only uses a very small amount of the CPU, 2 or 3 percent, usually
(this is with all of the highest priority settings). If this stat is true
and it sometimes, for some reason, bumped up to using the full 100% as it
should, this would account for the extreme speed up.

    So, what seems reasonable? Well, when I render the animation I get about
1200 PPS, this is for the small size frames. If I render a single, large
frame (e.g., 1280 X 1024) then I get about 6500 PPS and the CPU usage goes
up to about 70 or 80%. If there was a way for the animation renderings to
continuously maintain the higher CPU usage and the higher PPS then that
would come close to accounting for the periodic speed up that I see.

    So, is there any way to maintain the high speed? Why, even on the large
frames, does POV only use 70 or 80% and not the full 100%? What do people
see on other systems, like Linux?


Thanks,

--Rainer


P.S. I actually have a dual CPU system and all of the CPU usage percentages
shown about are double the amount I see. I believe the above is what I would
see in a single CPU system.

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Here I go replying to myself...

    I've done a bit more testing and I've found this:

    I downloaded the MSDOS version and ran it on the same scene as before.
This was in a DOS box within NT. I found that the animation was rendered
about 125% faster in the MSDOS version (44 seconds vs 99 seconds). I also
rendered a single large image and it was about 21% faster (57 seconds vs 69
seconds).
    I know that the Windows version has a certain amount of extra overhead
(displaying PPS, etc) but it seems excessive.

    Another thing I've noticed is that the povray process will occassionally
jump up and use a lot of the CPU even when I'm NOT rendering (i.e., just
doing edits). The odd thing is that when this happens the editor will freeze
for a few seconds. This happens even though the editor's priority is set
higher than the renderer.


    Has anyone else seen anything like this? I remember seeing someone else
w/ NT seeing very little CPU usage.


Thanks,

--Rainer

Post a reply to this message

Rainer Mager <rvm### [at] cyberadjp> wrote:
:     I downloaded the MSDOS version and ran it on the same scene as before.
: This was in a DOS box within NT. I found that the animation was rendered
: about 125% faster in the MSDOS version (44 seconds vs 99 seconds). I also
: rendered a single large image and it was about 21% faster (57 seconds vs 69
: seconds).

  If you boot to raw dos (from a floppy disk or whatever) and render then,
you should get even more speed since the dos-box of winNT is rather slow.

-- 
                                                           - Warp. -

Post a reply to this message

In article <361dfd45.0@news.povray.org>, war### [at] assaricctutfi says...
>
>  If you boot to raw dos (from a floppy disk or whatever) and render then,
>you should get even more speed since the dos-box of winNT is rather slow.
>
>-- 
>                                                           - Warp. -

I didn't know that Pov could run in a dos box under NT;
(never really used NT myself neither)
People told me that the dos-extender would prevent it to run...
Mmmh, I'll give it a try...

Cheers,
Fabien.

Post a reply to this message

Rainer Mager wrote:
> 
>     I downloaded the MSDOS version and ran it on the same scene as before.
> This was in a DOS box within NT. I found that the animation was rendered
> about 125% faster in the MSDOS version (44 seconds vs 99 seconds). I also
> rendered a single large image and it was about 21% faster (57 seconds vs 69
> seconds).
>     I know that the Windows version has a certain amount of extra overhead
> (displaying PPS, etc) but it seems excessive.
--

What do you have the render priority (RENDER/RENDER PRIORITY) set to in
the
windows version? The default is NORMAL, which lets POV co-exist with the
other
windows applications. If you set it to HIGHEST, it will preempt all
other
applications and your times (windows vs. dos) should be closer.

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