5.2.1 performance issue

[Kevin Oberman]

> Date: Thu, 12 Aug 2004 19:19:09 -0700 (PDT)
> From: Doug White <dwhite at gumbysoft.com>
> Sender: owner-freebsd-stable at freebsd.org
> 
> On Wed, 11 Aug 2004 igor at ktts.kharkov.ua wrote:
> 
> > I noticed that box started getting input errors on em0.
> > In order to fix that I increased EM_MAX_TXD from 256 to 1024 and
> > EM_MAX_RXD from 256 to 2048.
> > After that Input errors disappeared but I continued getting intr_queue_drops
> > counter increasing.
> 
> You might double check your duplex settings, and if you're on a managed
> switch, the stats there. It may  not have autonegotaited properly after
> the reboot.
> 
> Also make sure you aren't running with WITNESS and INVARIANTS. Those are
> big CPU pigs.

WITNESS is certainly a big CPU hog, but I don't see why INVARIANTS would
be all that significant. And both are disabled in 5.2.1 GENERIC.

I'd bet on either a duplex mis-match or an auto-negotiation
failure. Both are very common and the latter can be a pain to deal
with. (Don't assume that you can just nail up one end.)
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634