RE: does intel X520-SR(ixgbe) support RSS on single VLAN?

-----Original Message-----
From: Ben Hutchings [mailto:bhutchings@solarflare.com]
Sent: Tuesday, January 25, 2011 11:06 AM
To: Rui
Cc: Alexander Duyck; netdev@vger.kernel.org; e1000-
devel@lists.sourceforge.net
Subject: Re: does intel X520-SR(ixgbe) support RSS on single VLAN?

On Tue, 2011-01-25 at 10:10 +0800, Rui wrote:

quoted

On Tue, Jan 25, 2011 at 1:09 AM, Alexander Duyck
[off-list ref] wrote:

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On 1/24/2011 6:18 AM, Rui wrote:

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hi
does intel X520-SR support RSS on single VLAN?

tested with 3 different vlan id and priority packets
What I saw is that all packets were always delivered to the same

RxQ.

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looks can not get a different RSS index for these packet?
any setting needed?
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The X520 should have no problems hashing on a single VLAN tagged

frame.

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 However the VLAN will not be a part of the RSS hash.  The  only

components

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of the hash are the IPv4/IPv6 source and destination addresses, and

if the

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flow is TCP then the port numbers.

hi alexander
I got these information from the intel community:

'I asked our software engineers about your question, and this is what

I learned.

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You cannot filter by just VLAN or VLAN priority.  The L4 type will
also play a role in the filter and as such you would only be able to
filter TCP, UDP, and SCTP packets that are bound for a VLAN.
The command itself to setup a filter is “ethtool –U ethX flow-type
tcp4 vlan 0x2000 vlan-mask 0xE000 action Y” where X is the correct
index for the interface and Y is the queue you want to route the
traffic to.  This would have to be repeated for udp4 and sctp4.
I hope this will help.
Mark H"

The mask specifies bits to be ignored, so if you want to filter on the
basis of only the priority bits you should use vlan-mask 0xfff.  Unless
this is another inconsistency I failed to notice...

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so my question is that the VLAN is PART of the RSS or not?

It's not part of any specified Toeplitz hash.  However, some hardware
supports adding the hash (after indirection) to the queue number
specified by a filter.  Currently the ethtool API doesn't have a way to
request that.

quoted

looks the
perfect filter support vlan id ?can the perfect filter support
wildchar,such as: flow-type ANY?

It is possible to specify this using flow-type ether, but the ixgbe
driver does not yet support that (and I have no idea whether the
hardware does).

ethtool –U ethX flow-type tcp4 vlan 0x2000 vlan-mask 0xE000 action Y”

I got this msg:
Cannot add new RX n-tuple filter: Operation not supported
This command is only supported after 2.6.24?

Quoted:

"ethtool: Introduce n-tuple filter programming support

author Peter P Waskiewicz Jr [off-list ref]  
 Thu, 11 Feb 2010 04:03:05 +0000 (20:03 -0800) 
committer David S. Miller [off-list ref]  
 Thu, 11 Feb 2010 04:03:05 +0000 (20:03 -0800) 

This patchset enables the ethtool layer to program n-tuple
filters to an underlying device.  The idea is to allow capable
hardware to have static rules applied that can assist steering
flows into appropriate queues.

Hardware that is known to support these types of filters today
are ixgbe and niu.

Signed-off-by: Peter P Waskiewicz Jr <redacted>
Signed-off-by: Jeff Kirsher <redacted>
Signed-off-by: David S. Miller <davem@davemloft.net>
"

Ben.

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