TSO and FreeBSD vs Linux

[David Wolfskill]

On Tue, Sep 03, 2013 at 12:27:34PM -0700, David Wolfskill wrote:
> ...
> As soon as I issued "sudo net.inet.tcp.tso=0" ... the copy worked without
> a hitch or a whine.  And I was able to copy all 117709618 bytes, not just
> 2097152 (2^21).

The above command should (of course) have read

	sudo sysctl net.inet.tcp.tso=0

Also: I normally had the em0 NIC on the machine in question connected to
a Netgear GS105 (5-port Gigabit switch).  In the process of
trouble-shooting the problem with NFS writes, I bypassed that switch and
connected the em0 NIC directly to the jack in my cube.

In that configuration, the em0 NIC showed "media: Ethernet 1000baseT
(autoselect)", while connected to the GS105, it showed "media: Ethernet
100baseTX (autoselect)".

While the NFS write worked whether or not I had the GS105 in the path,
it seemed ... suboptimal ... to have a NIC capable of 1000baseT
connected to a Gigabit switch, but negotiating at 100baseTX.

So I tried setting the media via "ifconfig em0 media 1000baseT"; after a
few seconds, it finally woke back up, and now reports "media: Ethernet
1000baseT (1000baseT <full-duplex>)".

So it appears that the em(4) driver and Intel 82578DM NIC fail to
negotiate 1000baseT with the Netgear GS105.

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
Taliban: Evil cowards with guns afraid of truth from a 14-year old girl.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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