Error allocating DMA channel with NI-DAQmx Base 2.0, Mac OS X

[Jeremy Willden]

I recently ran into this problem again, and haven't taken the time to re-architect my application (as suggested elsewhere in this thread).  The situation was even worse this time, I was unable to complete even a 2-sample single-shot acquisition.  Apparently NI-DAQmx Base allocates a minimum of 8k in the kernel for the DMA operation, no matter how small the acquisition.  The fact that a single 8k allocation would fail told me there was a lot of kernel memory fragmentation going on (or perhaps some other issue with allocation).  This is a system that I almost never reboot, and it currently has about a 300 day uptime.  Perhaps never logging out is somehow related as well, because after logging out and back in, I was able to do acquisitions again.  Not a long-term fix, but perhaps a useful clue to anyone tracking a similar issue.

[sth]

That is interesting. But logging out and logging back in should not usually free up kernel space. Quitting LV may unload some reserved kernel space as client side drivers are quit. The only way that logging out should help is if there are other user tasks that are taking up kernel space. Possibly the window server but there may be others.

[Jeremy Willden]

Interesting that you would mention quitting and restarting LabVIEW.  I tried doing that before logging out and back in, but it didn't help.