We use the /3GB switch here on some of our render nodes here and Maya 8.5 . The Switch does what it says :)
-S
On 11/19/07 5:09 PM, "Greg Ercolano" <erco@(email surpressed)> wrote:
[posted to rush.general]
> We sometimes get a "Memory use" error from Maya when we run
> some large renders. We have 4 gigs on our XP (32 bit) machines,
> and rushtop shows we're only using about 1/3 of the memory even
> rendering one frame per box, but still the renders crash. eg:
>> ====================================>> Memory use when exception was thrown
>> ====================================>> ====================================>> 328197 Page faults
>> 1607.969 Mb Max resident size <-- 1.6Gig ram use
>> 1636.184 Mb Peak total size(Estimated) <--
>> 1364.286 Mb Peak arena size
> Why would the render crash if Maya is only using 1/3 of the machine?
Windows XP 32bit can't access more than ~1.5G by default,
based on its default configuration. This is why folks go
with 64bit machines lately.
This page for 'blender' describes some technical details on that:
http://mpan3.homeip.net/?blendermemory
..these details being relevant to /all/ windows 32bit apps.
Nice thing about the above page is it describes the "/3G" OS tweak
to the WinXP boot.ini file that apparently lets you raise the
process limits a bit (I haven't tried this).
If you'd prefer to see the Microsoft docs on this flag, see:
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx
http://www.microsoft.com/technet/sysinternals/information/bootini.mspx
Microsoft's description of the /3GB flag:
"Increases the size of the user process address space from 2 GB to 3 GB
(and therefore reduces the size of system space from 2 GB to 1 GB).
Giving virtual-memory- intensive applications such as database servers
[..and 3D rendering software! -erco] a larger address space can improve
their performance. For an application to take advantage of this feature,
however, two additional conditions must be met: the system must be running
Windows XP, Windows Server 2003, Windows NT 4 Enterprise Edition, [..]
and the application .exe must be flagged as a 3-GB-aware application.
Applies to 32-bit systems only."
I'm not certain if apps like Maya/Shake/etc meet that last qualifier.
Regarding a more technical description of the 4G/2G/1.5G limitations,
I like some of the descriptions in this sysinternals thread, which is
probably MTYEWTK:
http://forum.sysinternals.com/forum_posts.asp?TID013
Long story short, this is a normal per-process limit with Windows
on 32 bit machines. The above /3GB flag may help you get a bit more
ram per process, but you'll still hit a wall lower than 4G. The only
way to get all 4G active is to have more than one render process
using the machine at the same time. Or, get a 64bit machine running
the 64bit OS with 64bit binaries for the renderer.
|