Re: Netxen packet loss with VLANs and LRO (was: [PATCH] netxen: fix LRO disable warning)

On Tue, Apr 05, 2011 at 12:38:11AM -0500, Amit Salecha wrote:

quoted

On Mon, Mar 21, 2011 at 03:37:08AM -0700, Amit Kumar Salecha wrote:

quoted

netxen_nic_set_flags() rejects data if other flag than ETH_FLAG_LRO

is set.

quoted

Driver also supports NETIF_F_HW_VLAN_TX.
Now compare data with ethtool_op_get_flags(), to get all supported

features.

Could that be the cause for packet loss on kernel 2.6.38.2 if:

  - receiving card is NX3031 [4040:0100]
  - frames are received with VLAN tags
  - large received offload is on.

If ip_forwarding or routing is enable ....then you may see packet loss.

The box is intended to route, so disabling routing is
contraproductive. I just would like to download software updates to
the box with decent speed as well.

quoted

Packet Loss of this kind is noticed when doing TCP data transfers
towards the host with the Netxen Interface and the TCP session is
terminated on the Netxen host itself. TCP sessions routed through the
Netxen host are not affected.

My ethtool doesn't allow me to influence the LRO setting alone - it is
disabled when I set rx off but doesn't come on again when rx is set to
on again. So, ethtool -K rx off, ethtool -K rx on fixes the issue.

If rx csum is disabled, LRO will be disable. LRO won't be enabled automatically if you enable rx csum.
You need to explicitly enable LRO.

Explicitly enabling LRO does not work ("invalid argument", if I recall
correctly).

quoted

Is this a known bug, maybe with an available patch?

You need to retest with this patch
http://patchwork.ozlabs.org/patch/88060/. This patch got applied
instead of mine.

Will that patch fix the behavior of the interface regarding the packet
loss, or only its connection to ethtool?

Greetings
Marc

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