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Date:      Thu, 4 Oct 2001 18:54:26 -0400 (EDT)
From:      Andrew Gallatin <gallatin@cs.duke.edu>
To:        Bsdguru@aol.com
Cc:        hackers@freebsd.org
Subject:   Re: 64bit Ethernet Card (if_sf driver)
Message-ID:  <15292.59554.280315.109732@grasshopper.cs.duke.edu>
In-Reply-To: <137.296ca27.28edf63e@aol.com>
References:  <137.296ca27.28edf63e@aol.com>

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Bsdguru@aol.com writes:
 > 
 > Anyone with experience or ideas?
 > 

Because of the aligment constraints of the card, its copying every
single packet the driver recvs.  This is required on alpha (and
possibly other platforms) to prevent an unlaligned access.  In a
forwarding situation on an x86, it is suboptimal.

Try making the m_devget in the rcv handler conditional on !i386 (see
http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/nge/if_nge.c.diff?r1=1.13.2.2&r2=1.13.2.3
for an example of how to change this)

I'd be interestd to hear (quantitatively) how much your perf changes.

Drew

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