Running out of memory - not accessing Virtual Memory

Question

Hi there,
I am working on a vision application, and trying to process very large images.
Environment:
LabVIEW 2014 (14.0f1) 64-bit
Vision Development Module 2014
Vision Acquisition Software 2014
Windows 7 Professional SP1 64-bit Settings:
Physical RAM = 8GB
Virtual RAM Settings:
Unchecked: "Automatically manage paging file size for all drives"
Checked: "Custom Size"
Initial Size (MB): 12094
Maximum Size (MB): 24188
I read in a sequence of images in the LabVIEW application and stitch it together.  I observe (via Task Manager) the physical memory rise up to approx 7.6GB, and then I am getting the "Out of Memory Error".
So it doesn't seem to be accessing the virtual memory I have allocated? Is there a setting for this that I am missing?
Thanks
Christopher Farmer
Certified LabVIEW Architect
Certified TestStand Developer
http://wiredinsoftware.com.au

Answer 1

LabVIEW does need a contiguous block of memory for every data structure it creates. In addition its arrays are traditionally limited to 2^31-1 elements per dimension since the count member of an array is treated as signed 32 bit integer. This 2^31 limitation very likely doesn't come into play here since IMAQ Vision uses its own internal memory structures and treats IMAQ Vision handles as pointers rather than LabVIEW data handles to make it less prone to unintentional memory copies of the data.
Basically image memory only gets copied when explicitedly calling IMAQ Vision functions or when passing an image to an image control for display in a window. And that is pretty much unavoidable.So if you create an image that uses 4GB of memory you quickly end up consuming 2 or 3 blocks of contiguous 4GB memory. Due to memory fragmentation, even if your system has still 4 or more GB of memory free, calling a function that (temporarely) causes another copy in memory of that 4GB image may still fail, since there is no contiguous block of memory available anymore in the system. And yes that data has to be in physical memory as it is actively used at that moment.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions