subVIs memory deallocation

[Gavrilo]

Hi !

I have a pretty large labview interface, and am starting to have performance issues, and continuous increase of usage of RAM. I'm tempted to put memory deallocation requests in all of my sub-vis, but I don't know whether this is the best thing to do.

My question is : if LabView uses periodically one same subVI, does it allocate for it new memory at each time, or does it use the previously allocated memory? Which is, will memory deallocation requests augment the performances of my interface, or will it slow it down by adding unncessary memory allocations?

Thanks in advance for any help!!

[LAVA 1.0 Content]

QUOTE(Gavrilo @ Oct 15 2007, 08:14 AM)

... will memory deallocation requests augment the performances of my interface, or will it slow it down by adding unncessary memory allocations?

Thanks in advance for any help!!

If the buffers used for all of the wires in the sub-Vi are large enough, the same buffers should be re-used.

The last time I poked around with the de-allocate, it only cam e into play when the VI in question was marked for removal from memory. If the sub-VI is part of the app (not dynamic) it will not be marked for removal while the top-level VI is running.

On the other hand, if the VI ws loaded dynamically, then when all of its references are closed, the de-allocation is possible.

Stepping back:

I think of that switch as being useful if you have a set of functions that are called as a response to a user action, are used, and then are unloaded.

All of the above is just my opinion based on personal observations.

If anyone actually KNOWS what is happening, please step up and correct me, PLEASE!

Re: more memory

If your VI is using more virtual memory than you have physical memory, then adding physical meemory will help.

If you are using less virtual than physical, then use the profile tool to find who using the pig, then review that/those critters for excessive buffer copies.

Trying to help,

Ben

[Aristos Queue]

This is a question that would be better to post to DevZone than to LAVA. The developers who would know about the Dealloc prim tend to monitor DevZone and not LAVA. There are also AEs who have played around with that prim's behavior. If you do post to DevZone, be sure to add a post here to link to the other topic.

[Gavrilo]

Thanks for your help!

indeed, there is a quite useful topic about this in DevZone :

http://forums.ni.com/ni/board/message?boar...=563986#M142503