On Tue, 15 May 2012 11:20:19 -0500
Corbin [off-list ref] wrote:

I agree that losing bytes in the software layer wouldn't happen under
normal circumstances, but it is still important to know when it
happens. My understanding was that the overrun field in the port's
icount was for logging hardware overruns, while the buf_overrun field
should be used for software overruns. If this is not the case then is
there another method for determining when the software layer is losing
bytes?

It'll occur when the machine cannot even allocate a free page of memory.
So you'll get GFP spews in the kernel log to go with it.

Alan