I get a lot of ing buffer overflow messages using NFS and the ed0 driver. Is there a problem?
David Greenman (davidg@implode.rain.com), the original author of the ed0 driver, provides us with some insight into the inner workings of the ed0 driver. It always surprises me that people don’t just ask the original author these questions. 🙂 Anyway, the reason these are happening is that the access to the 8bit boards shared memory simply isn’t fast enough to deal with full wire speeds…but the driver tries hard…so even though packets get dropped, your performance only drops to about what the ethernet board is capable of (should be in the 400-600k range with an 8bit card). NFS is especially bad because the UDP window is quite large (40k last time I looked), so the overflow condition can happen easily. I’ve explained this for the most part in the release notes for the driver, but these didn’t make it into either the FreeBSD or NetBSD releases (we couldn’t find an appropriate place to put them). >From the release notes: receive The 8390 implements a shared memory ring-buffer to st
