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From: Ben Scheele
Subject: Odd behavior in rendering of scene
Date: 30 Mar 2006 13:48:11
Message: <442c27eb$1@news.povray.org>
Hey all.
I recently upgraded my CPU from an Athlon XP 1800+ to 3000+.  Of course 
I wanted to try benchmarking my system using POV-Ray.  I had stats for a 
few old scenes of mine, so I chose one and rendered it in the latest 
version of POV-Ray (3.6.1b).  Nice and fast, went from 1:04 down to 
0:51.  Then I tried rendering it again, and it took 1:14.  The next 
time, it took 1:25, then 1:34, then 1:41, 1:45.  Then it seemed to hover 
around that value.  When I restart my computer and repeat the process, 
it does a similar sequence.  The rendering time is always nearly the 
same, but the parsing time gradually increases to a saturation point.  I 
at first thought it might be an issue with the CPU, or memory, or their 
operating at different clock frequencies.  That doesn't seem to be the 
main issue, since it behaves in a similar way on our other computer, a 
Dell, too.  I also did lots of diagnostic tests, and everything checks 
out fine.  I think it may be an issue with POV-Ray itself.  Is it not 
freeing up memory?  What's going on in there?  It's a fairly simple 
little scene.  Other scenes where it's mostly rendering and doing little 
parsing are a lot more consistent.  It doesn't seem to have anything to 
do with the random number generation in the scene, because I tried it 
without it, too.  If anyone can offer some suggestions or answers as to 
what is going on, I'd greatly appreciate it.

------------------------------
Ben Scheele
Silmarillion: Ben's World
http://www.benscheele.com
------------------------------

Here's the scene:  (I've been rendering it at 320x240, antialias at 0.3)

camera{
   location 120*y
   look_at 0
   angle 40
}

light_source{ <50,300,20> rgb 1 }

background{ rgb .1 }

#declare r1 = seed(150);
#declare r2 = seed(200);
#declare r3 = seed(175);
#declare s = .35;
#declare d = .175;
#declare step = .25;

#declare E = 54;
#declare X = -E;
#declare EndX = E;
#while(X < EndX)

   #declare Z = -E;
   #declare EndZ = E;
   #while(Z < EndZ)
     #declare R = sqrt(X*X + Z*Z);

     #if (R <= E)

       #declare rot = 30*sin(d*R);

     box { -s, s
       pigment
{rgb<1+sin(d*R)+.3*rand(r1),.3+.3*rand(r2),1-sin(d*R)+.3*rand(r3)>}
       finish {phong 0.3 ambient 0.35}
     scale <step,1.5*rot+.001,step>
     translate <X,0,Z>
     rotate rot*y
     }

     #end

   #declare Z = Z + step;
   #end
#declare X = X + step;
#end


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From: Alain
Subject: Re: Odd behavior in rendering of scene
Date: 30 Mar 2006 18:02:12
Message: <442c6374$1@news.povray.org>
Ben Scheele nous apporta ses lumieres en ce 30/03/2006 13:47:
> Hey all.
> I recently upgraded my CPU from an Athlon XP 1800+ to 3000+.  Of course 
> I wanted to try benchmarking my system using POV-Ray.  I had stats for a 
> few old scenes of mine, so I chose one and rendered it in the latest 
> version of POV-Ray (3.6.1b).  Nice and fast, went from 1:04 down to 
> 0:51.  Then I tried rendering it again, and it took 1:14.  The next 
> time, it took 1:25, then 1:34, then 1:41, 1:45.  Then it seemed to hover 
> around that value.  When I restart my computer and repeat the process, 
> it does a similar sequence.  The rendering time is always nearly the 
> same, but the parsing time gradually increases to a saturation point.  I 
> at first thought it might be an issue with the CPU, or memory, or their 
> operating at different clock frequencies.  That doesn't seem to be the 
> main issue, since it behaves in a similar way on our other computer, a 
> Dell, too.  I also did lots of diagnostic tests, and everything checks 
> out fine.  I think it may be an issue with POV-Ray itself.  Is it not 
> freeing up memory?  What's going on in there?  It's a fairly simple 
> little scene.  Other scenes where it's mostly rendering and doing little 
> parsing are a lot more consistent.  It doesn't seem to have anything to 
> do with the random number generation in the scene, because I tried it 
> without it, too.  If anyone can offer some suggestions or answers as to 
> what is going on, I'd greatly appreciate it.
> 
> ------------------------------
> Ben Scheele
> Silmarillion: Ben's World
> http://www.benscheele.com
> ------------------------------
> 
Trying it with the current beta. My results using +b2
First render: Parse=26.978, bounding=15.011, trace=7:21
Second render:parse=26.788, bounding=13.859, trace=6:58
On an aging Athlon tbird 1400 and 512 Mb

-- 
Alain
-------------------------------------------------
I drive way too fast to worry about cholesterol.


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From: Ben Scheele
Subject: Re: Odd behavior in rendering of scene
Date: 30 Mar 2006 23:23:29
Message: <442caec1$1@news.povray.org>
Interesting.  Thanks for checking it out.  So it rendered faster the 
second time?  Hmm.  Yeah, I remember when it used to take me 6 minutes 
to render it.  It helps to have a few hundred MB of RAM free for doing 
that scene.

-Ben

Alain wrote:
> Ben Scheele nous apporta ses lumieres en ce 30/03/2006 13:47:
> 
>> Hey all.
>> I recently upgraded my CPU from an Athlon XP 1800+ to 3000+.  Of 
>> course I wanted to try benchmarking my system using POV-Ray.  I had 
>> stats for a few old scenes of mine, so I chose one and rendered it in 
>> the latest version of POV-Ray (3.6.1b).  Nice and fast, went from 1:04 
>> down to 0:51.  Then I tried rendering it again, and it took 1:14.  The 
>> next time, it took 1:25, then 1:34, then 1:41, 1:45.  Then it seemed 
>> to hover around that value.  When I restart my computer and repeat the 
>> process, it does a similar sequence.  The rendering time is always 
>> nearly the same, but the parsing time gradually increases to a 
>> saturation point.  I at first thought it might be an issue with the 
>> CPU, or memory, or their operating at different clock frequencies.  
>> That doesn't seem to be the main issue, since it behaves in a similar 
>> way on our other computer, a Dell, too.  I also did lots of diagnostic 
>> tests, and everything checks out fine.  I think it may be an issue 
>> with POV-Ray itself.  Is it not freeing up memory?  What's going on in 
>> there?  It's a fairly simple little scene.  Other scenes where it's 
>> mostly rendering and doing little parsing are a lot more consistent.  
>> It doesn't seem to have anything to do with the random number 
>> generation in the scene, because I tried it without it, too.  If 
>> anyone can offer some suggestions or answers as to what is going on, 
>> I'd greatly appreciate it.
>>
>> ------------------------------
>> Ben Scheele
>> Silmarillion: Ben's World
>> http://www.benscheele.com
>> ------------------------------
>>
> Trying it with the current beta. My results using +b2
> First render: Parse=26.978, bounding=15.011, trace=7:21
> Second render:parse=26.788, bounding=13.859, trace=6:58
> On an aging Athlon tbird 1400 and 512 Mb
>


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From: Manuel Kasten
Subject: Re: Odd behavior in rendering of scene
Date: 1 Apr 2006 03:51:10
Message: <442e3efe$1@news.povray.org>
Hi.

On my Athlon 64 3700+ it takes 40 seconds using a 32bit Debian Linux.
Of course as on Linux there isn't a frontend with POV, it exits 
comletely when the render is done, so subsequent renders take the same time.

Manuel

#####################################################################
Total Scene Processing Times
   Parse Time:    0 hours  0 minutes 12 seconds (12 seconds)
   Render Time:   0 hours  0 minutes 28 seconds (28 seconds)
   Total Time:    0 hours  0 minutes 40 seconds (40 seconds)


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From: Ben Scheele
Subject: Re: Odd behavior in rendering of scene
Date: 1 Apr 2006 23:42:17
Message: <442f5629$1@news.povray.org>
Good, more information; thanks Manuel.  I tried restarting the program, 
and that reset the time back to around my minimum.  That wouldn't help 
for animations, but it's good to know that that works, and I don't need 
to restart my whole computer to get that effect.  I still would like to 
know what's going on within the program that would cause that, but that 
would require insider information, it would seem.

------------------------------
Ben Scheele
Silmarillion: Ben's World
http://www.benscheele.com


Manuel Kasten wrote:
> Hi.
> 
> On my Athlon 64 3700+ it takes 40 seconds using a 32bit Debian Linux.
> Of course as on Linux there isn't a frontend with POV, it exits 
> comletely when the render is done, so subsequent renders take the same 
> time.
> 
> Manuel
> 
> #####################################################################
> Total Scene Processing Times
>   Parse Time:    0 hours  0 minutes 12 seconds (12 seconds)
>   Render Time:   0 hours  0 minutes 28 seconds (28 seconds)
>   Total Time:    0 hours  0 minutes 40 seconds (40 seconds)


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From: Chris Cason
Subject: Re: Odd behavior in rendering of scene
Date: 6 Apr 2006 22:13:20
Message: <4435cac0@news.povray.org>
Ben Scheele wrote:
> to restart my whole computer to get that effect.  I still would like to 
> know what's going on within the program that would cause that, but that 
> would require insider information, it would seem.

I tried this with the current 3.6.1c and cannot replicate the issue. Render
time stayed the same for each render. Given 3.6.1c doesn't fix any issues
related to memory or render time (vs 3.6.1b) I can't explain the cause of
your problem.

-- Chris


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From: Ben Scheele
Subject: Re: Odd behavior in rendering of scene
Date: 10 Apr 2006 14:01:36
Message: <443a9d80$1@news.povray.org>
Thanks for looking into this issue as well, Chris.  I tried installing 
this latest version and it still has that issue for me.  Here is a set 
of render stats for successive renderings.

Parse + Render = Total

16 + 36 = 0:52
41 + 37 = 1:18
49 + 36 = 1:25
56 + 37 = 1:33
60 + 36 = 1:36
63 + 36 = 1:39
68 + 37 = 1:45
75 + 36 = 1:51
76 + 36 = 1:52

The render time is fairly constant, but the parsing time is increasing 
until it reaches a saturation point eventually.  That does seem like an 
odd behavior, doesn't it?  Would you please describe your computer's 
setup, Chris (RAM, CPU, etc.)?  Thanks.

-Ben


Chris Cason wrote:
> I tried this with the current 3.6.1c and cannot replicate the issue. Render
> time stayed the same for each render. Given 3.6.1c doesn't fix any issues
> related to memory or render time (vs 3.6.1b) I can't explain the cause of
> your problem.
> 
> -- Chris


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From: Thorsten Froehlich
Subject: Re: Odd behavior in rendering of scene
Date: 10 Apr 2006 14:31:32
Message: <443aa484$1@news.povray.org>
Ben Scheele wrote:
> The render time is fairly constant, but the parsing time is increasing 
> until it reaches a saturation point eventually.

You you perhaps have a virus scanner installed that is interfering with the 
reading of files?

	Thorsten


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From: Alain
Subject: Re: Odd behavior in rendering of scene
Date: 11 Apr 2006 18:46:06
Message: <443c31ae$1@news.povray.org>
Thorsten Froehlich nous apporta ses lumieres en ce 10/04/2006 14:31:
> Ben Scheele wrote:
> 
>> The render time is fairly constant, but the parsing time is increasing 
>> until it reaches a saturation point eventually.
> 
> 
> You you perhaps have a virus scanner installed that is interfering with 
> the reading of files?
> 
>     Thorsten
I don't think that a virus scanner would cause progressively increasing parse time. It
would tend to 
increase the first render time, then have a decreased, constant, effect on successive
render. RAM 
fragmentation can cause this progressive increasing in parse time.

-- 
Alain
-------------------------------------------------
Fundamentalism #3: Shit must be born again.


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From: Ben Scheele
Subject: Re: Odd behavior in rendering of scene
Date: 15 Apr 2006 01:15:54
Message: <4440818a$1@news.povray.org>
Hey, thanks Thorsten and Alain.  I don't use an antivirus program, so 
that couldn't be an issue.  I researched RAM fragmentation and that is 
likely the culprit.  Aside from paying $15 for some RAM defragmenter 
that may or may not improve performance, is there some tweak that can be 
done in POV-Ray to get it to behave properly?

-Ben

Alain wrote:
> Thorsten Froehlich nous apporta ses lumieres en ce 10/04/2006 14:31:
> 
>> Ben Scheele wrote:
>>
>>> The render time is fairly constant, but the parsing time is 
>>> increasing until it reaches a saturation point eventually.
>>
>>
>>
>> You you perhaps have a virus scanner installed that is interfering 
>> with the reading of files?
>>
>>     Thorsten
> 
> I don't think that a virus scanner would cause progressively increasing 
> parse time. It would tend to increase the first render time, then have a 
> decreased, constant, effect on successive render. RAM fragmentation can 
> cause this progressive increasing in parse time.
>


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