"e100" ethernet driver problem in AC-1.0 and Centos-4.2

[Jay Estabrook]

[The "e100" driver is used for Intel NIC chipsets 82557/8/9.]

The "e100" NIC driver in current AC-1.0 and Centos-4.2 kernels
(2.6.11-1.1180axp_FC3 and 2.6.9-22.EC, respectively), has a problem
with causing large numbers of kernel unaligned accesses.

Doing an NFS "Everything" install of AC-1.0 caused more than 10 million
unaligned accesses from the "e100" driver. I'm expecting the NFS install
of CentOS-4.2 to be roughly the same.

But this affects ALL network traffic, not just NFS installs (that was just
an example of the magnitude of the problem).

Someone needs to fix this in our kernels (perhaps its already done in
later ones but not backported?), but in the meantime, thankfully,
there's an easy work-around: replace the "e100" driver with the
"eepro100" one, which doesn't have the problem.

You can test for use of "e100" by:

	lsmod | grep e100

You can replace it on a running system by (at the console):

	service network stop
	rmmod e100
	modprobe -v eepro100
	service network start

And finally, edit the /etc/modprobe.conf line:

	alias eth0 e100

to be

	alias eth0 eepro100

so it will use the other driver on the next reboot.

I think these techniques are OK; if not, someone please correct me.

Here's to more efficient network activity on Alpha... ;-}

 --Jay++

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Jay A Estabrook                            HPTC - XC I & B
Hewlett-Packard Company - ZKO1-3/D-B.8     (603) 884-0301
110 Spit Brook Road, Nashua NH 03062       Jay.Estabrook at hp.com
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