Subject: Re: Handling of short frames in gem(4) (was: CVS commit: src/sys/dev/ic)
To: None <source-changes@NetBSD.org>
From: David Laight <david@l8s.co.uk>
List: source-changes
Date: 01/02/2008 22:08:57
On Wed, Jan 02, 2008 at 03:40:19PM -0600, David Young wrote:
> 
> If you
> mean that scatter/gather is expensive, then let us see some measurements
> of how expensive.

Years ago, somewone I know got a break-even point of about 1k [1] for an
mbus/sbus sparc system (running a SYSV variant).  I've also got significant
improvements from removing 'buffer loaning' and all its complications
by inserting a data copy from a solaris (old) FDDI driver.

	David

[1] I'm also not sure he ensured the data copies where aligned (test data
wouldn't have been IP).

-- 
David Laight: david@l8s.co.uk