Date: Fri, 13 Jan 2012 18:01:51 -0500 From: Andrew Boyer <aboyer@averesystems.com> To: Jack Vogel <jack.vogel@intel.com> Cc: freebsd-net@freebsd.org, Ryan Stone <rysto32@gmail.com> Subject: Bad interaction between 82599 hardware RSC and VLANs Message-ID: <10A2858D-8DA8-45C4-B9A6-00CFA172404F@averesystems.com>
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Hello Jack,
I'm seeing an issue on 82599 controllers. When hardware RSC is used, =
large VLAN packets arrive without the VP bit set, even though the vtag =
in the descriptor is correct. It totally kills the receive performance. =
Turning off hardware RSC in the driver (falling back to software LRO) =
works fine, as does turning off LRO entirely.
I've worked around the problem for now by overriding the VP bit if =
ixgbe_rxeof() finds a valid vtag in the descriptor.
Have you seen this before?
It's not in the latest errata. It almost seems to be the opposite of =
what Ryan reported in November 2010 ("82599 receiving packets with vlan =
tag=3D0 (vlan strip problem)?").
Thanks,
Andrew
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Andrew Boyer aboyer@averesystems.com
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