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Date: Thu, 8 Sep 2011 18:49:28 +0000
From: Navdeep Parhar <np@FreeBSD.org>
To: John Baldwin <jhb@freebsd.org>
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	Ben Hutchings <bhutchings@solarflare.com>,
	Takuya ASADA <syuu@dokukino.com>, jfv@freebsd.org
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Cc: Ben Hutchings <bhutchings@solarflare.com>, freebsd-net@freebsd.org,
	jfv@freebsd.org, Takuya ASADA <syuu@dokukino.com>
Subject: Re: Adding Flow Director sysctls to ixgbe(4)
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On Thu, Sep 08, 2011 at 08:34:11AM -0400, John Baldwin wrote:
> On Monday, September 05, 2011 7:21:12 am Ben Hutchings wrote:
> > On Mon, 2011-09-05 at 15:51 +0900, Takuya ASADA wrote:
> > > Hi,
> > > 
> > > I implemented Ethernet Flow Director sysctls to ixgbe(4), here's a detail:
> > > 
> > > - Adding removing signature filter
> > > On linux version of ixgbe driver, it has ability to set/remove perfect
> > > filter from userland using ethtool command.
> > > I implemented similar feature, but on sysctl, and not perfect filter
> > > but signature filter(which means hash collision may occurs).
> > [...]
> > 
> > Linux also has a generic interface to RX filtering and hashing
> > (ethtool_rxnfc) which ixgbe supports; wouldn't it be better for FreeBSD
> > to support something like that?
> 
> Some sort of shared interface might be nice.  The cxgb(4) and cxgbe(4) drivers
> both provide their own tools to manipulate filters, though they do not
> provide explicit steering IIRC.

Both of them can filter as well as steer (and the tools let you do that).
cxgbe(4) can do a lot more (rewrite + switch, replicate, etc.) but those
features are perhaps too specialized to be configurable via a general
purpose tool.

> 
> We would need to come up with some sort of standard interface (ioctls?) for 
> adding filters however.

+1 for a standard interface.

imho the kernel needs to be aware of the rx and tx queues of a NIC, and
not just for steering.  But that's a separate discussion.

Regards,
Navdeep