Re: NetBSD 5.0.1 Networking Message

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sun, Aug 16, 2009 at 06:07:59AM -0700, Andy Ruhl wrote:
> On Sun, Aug 16, 2009 at 4:33 AM, Manuel Bouyer 
> <bouyer%antioche.eu.org@localhost>wrote:
> 
> > > ex1:  transmit underrun (9000) @20
> >
> > This means the 3com chip couldn't get data fast enough from the PCI bus.
> > THis is usually because another device (or possibly the CPU) holds the PCI
> > bus for too long. It's probably happening only once in a while (no more
> > than
> > once every 256 packets) otherwise it would have bumped the TX threshold.
> >
> 
> This is just a quesiton to anyone:
> 
> If this is the case, does it help to activate the checksum features built
> into the adapter?:
> 
> ex0: flags=8863<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> 
> capabilities=3f00<IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx>
> 
> I guess the answer is probably: "It might."

Yes, It might in the sense that it may decrease traffic between CPU and
memory. but my guess is that the packet would already be in the
CPU's cache so there's not much to win here.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--