Adding Flow Director sysctls to ixgbe(4)

[K. Macy]

On Thu, Sep 8, 2011 at 2:34 PM, John Baldwin <jhb at freebsd.org> 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.
>
> We would need to come up with some sort of standard interface (ioctls?) for
> adding filters however.

I know this must sound like nitpicking, but please don't add more
ioctls if you can avoid it. If you want to add new interfaces try to
stick with sysctl as it tends to be less prone to breakage across
releases.


The biggest problem in defining a new API is the lack of anyone with a
global overview of the functionality provided by NIC vendors and their
near-term roadmaps. It doesn't make sense to add an API that we only
know works for one or two vendors.


Cheers