Why Am I Unable to Use All of the Available Memory on My SPEEDY-33, 6711 DSK, or 6713 DSK?Primary Software: LabVIEW Modules>>DSP ModulePrimary Software Version: 1.0 Primary Software Fixed Version: N/A Secondary Software: N/A
Problem: When I target a DSP evaluation board such as the SPEEDY-33, 6711 DSK, or 6713 DSK, it seems as if I cannot use 100% of the total memory available. Instead, I receive the following error: ERROR: One or more of the memory regions on the target cannot be allocated. The amount of memory used in the VI is exceeding the available memory on the target.I receive this error even when LabVIEW DSP Module Status Monitor says that I am using less than 100% of the available memory. In this case, the status monitor shows that my DSP VI is only using 97.299% of available memory. Why am I unable to use the remaining memory? Solution: In most cases, you will not be able to use 100% of the memory on the DSP target due to memory fragmentation. For various reasons, the DSP cannot store data contiguously in memory. This results in unusable gaps in the memory. In the case where the status monitor shows that the DSP VI only uses 97.299% of available memory, this gap seems rather large (2.701%). In reality, this large gap is actually many small, unusable gaps spread throughout the memory on the DSP target. This behavior is analogous to the difference between filling a glass with water and filling a glass with ice. Water can fill the glass 100% because it is flexible enough to squeeze into every part of the container. Because ice is more structured, it leaves holes or gaps between the pieces. Even when the glass is full of ice, there is still room in the glass because of these gaps. The code that the LabVIEW DSP Module generates is similar to the ice in this example and the memory on the DSP target is the glass. The DSP code has pieces with fixed size and alignment that prevent the code from fitting into the memory perfectly. In addition, depending on the design of the DSP targets, the total memory might have two or more memory segments to fill. In terms of the analogy, this means that instead of filling one large glass with ice, you fill several smaller glasses of ice, which might create more space that is unusable. Because the DSP Module allocates memory on the DSP target for front panel controls and indicators, you might limit these items to use less memory on the DSP target. Refer to the Disconnecting Front Panel Indicators topic in the LabVIEW Help for more information about using front panel controls and indicators in DSP VIs. Related Links: Attachments:
Report Date: 05/26/2005 Last Updated: 11/22/2005 Document ID: 3LPBABAJ |
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