comp.lang.idl-pvwave archive: archive » Memory management by 5.4 on Sunblade

Home » Public Forums » archive » Memory management by 5.4 on Sunblade

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: Memory management by 5.4 on Sunblade [message #28610 is a reply to message #28523]

Wed, 19 December 2001 21:50

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

JD Smith <jdsmith@astro.cornell.edu> writes:
> Timm Weitkamp wrote:
>>
>> Hi,
>>
>> I'm mostly using IDL 5.4 on my laboratory's Linux86 cluster, and
>> running memory-critical simulation code on it which uses lots of large
>> temporary arrays.
>>
...
>> However, I noticed that memory management by IDL 5.4 on the Sunblade
>> is extremely poor in that variable space "freed" by TEMPORARY, DELVAR,
>> or simply by dynamic resizing of a variable is not actually freed but
>> kept allocated (so tells me "top").
...
>
> It's not a *bug*, it's a *feature*. IDL allocates memory as necessary
> from the OS, and then, even if it doesn't need it any more, hangs onto
> it just in case. This is true I think on all platforms, and all recent
> versions of IDL. You still have the memory available, just not to the
> system as a whole.

Hi JD--

I do not think this is always true. I find that I regularly create
300 MB arrays in memory, and then free them. While the procedure is
running, the memory usage is indeed around 300 MB, but afterwards the
memory use, as reported by the external program "top", drops down
again to the quiescent level.

If I recall correctly, there was a bally-hoo in one of the What's News
from ages ago about IDL using an allocator that is able to release
memory back to the system. *However*, this is surely (a) extremely
system dependent; and (b) not always possible depending on the
fragmentation of the memory at the time. Perhaps this is what Timm is
running in to.

Good luck Timm!
Craig

--
------------------------------------------------------------ --------------
Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
------------------------------------------------------------ --------------

Report message to a moderator

[Message index]

		Memory management by 5.4 on Sunblade By: weitkamp on Mon, 17 December 2001 02:57
		Re: Memory management by 5.4 on Sunblade By: John-David T. Smith on Wed, 19 December 2001 14:41
		Re: Memory management by 5.4 on Sunblade By: John-David T. Smith on Thu, 20 December 2001 10:50
		Re: Memory management by 5.4 on Sunblade By: Craig Markwardt on Wed, 19 December 2001 21:50
		Re: Memory management by 5.4 on Sunblade By: David Fanning on Thu, 20 December 2001 08:57
		Re: Memory management by 5.4 on Sunblade By: John-David T. Smith on Thu, 20 December 2001 08:51
		Re: Memory management by 5.4 on Sunblade By: weitkamp on Thu, 20 December 2001 02:36
		Re: Memory management by 5.4 on Sunblade By: Nigel Wade on Thu, 20 December 2001 01:45

Previous Topic:	Unsatisfactory 'file_test()' behavior
Next Topic:	Re: license problem

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Thu Oct 09 04:46:47 PDT 2025

Total time taken to generate the page: 0.88016 seconds