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28 Dec 2024 05:39:31 EST (-0500)
  Most RAM you've ever used for a scene (Message 1 to 4 of 4)  
From: jhu
Subject: Most RAM you've ever used for a scene
Date: 3 Jul 2012 20:05:01
Message: <web.4ff387c273cb9cead19b0ec40@news.povray.org>
Currently, 15GB on my computer that only has 16GB! It's headless and still
responsive. Then I realized why, rearranged the code, and went back down to
using 6GB.


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From: D103
Subject: Re: Most RAM you've ever used for a scene
Date: 3 Jul 2012 21:40:00
Message: <web.4ff39dc7908f18395ae2687f0@news.povray.org>
"jhu" <nomail@nomail> wrote:
> Currently, 15GB on my computer that only has 16GB! It's headless and still
> responsive. Then I realized why, rearranged the code, and went back down to
> using 6GB.

Just under 3.5GB out of 8, on my i7. I was just testing the computer's
performance at that amount of memory usage and data i/o by rendering a
16384x16384 image. After a few minutes, I was convinced of it's powers... ;)

D103


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From: Ger
Subject: Re: Most RAM you've ever used for a scene
Date: 4 Jul 2012 02:23:59
Message: <4ff3e17f@news.povray.org>
jhu wrote:

> Currently, 15GB on my computer that only has 16GB! It's headless and still
> responsive. Then I realized why, rearranged the code, and went back down
> to using 6GB.
The revisited Asbak image I posted a little while ago used 28GB.

-- 
Ger


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From: clipka
Subject: Re: Most RAM you've ever used for a scene
Date: 4 Jul 2012 07:27:12
Message: <4ff42890$1@news.povray.org>
Am 04.07.2012 02:01, schrieb jhu:
> Currently, 15GB on my computer that only has 16GB! It's headless and still
> responsive. Then I realized why, rearranged the code, and went back down to
> using 6GB.

11 GB out of 6 (!), testing a bugfix for an error scenario involving a 
86400 x 43200 pixels PPM image map (requiring 10.4 GB alone). Most of 
the render time consisted of loading that image map into memory. The 64 
bit Windows 7 system stayed comparatively responsive, despite obviously 
having to utilize virtual memory. (The bugfix proved effective; the 
earlier 3.7 RC5 would instead erroneously allocate far less memory and 
then crash.)

12 GB out of 6, trying to render to a 86400 x 43200 pixels PPM output 
file (guess for what purpose). The image data was accumulated on hard 
disk in a 69 GB temporary file (which took 20 minutes even to create) 
rather than main memory, but memory consumption still kept rising during 
render for then-unknown reasons, ultimately resulting in a crash of 
POV-Ray when the (fixed) virtual memory limit was hit. The 64 bit 
Windows 7 system had become totally uncontrollable by then.

Lesson learned: On Windows systems, do /not/ attempt to render simple 
scenes like a chrome sphere on a checkered plane at excessively high 
resolutions. It turns out that the render threads may pump image data 
into the inter-thread message queue at a faster rate than the front-end 
thread can write them to their designated location in the temporary 
file, causing the message queue to grow slowly but steadily past all 
limits. (I guess that having virtual memory on the same physical disk as 
the temporary file will make things even worse as soon as swapping sets 
in, by reducing I/O performance even more; I didn't bother to try - my 
swap file is on a separate one, and that was bad enough.)


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