Re: [dpdk-dev] [PATCH v3 1/3] fm10k: enable FTAG based forwarding

[David Marchand <david.marchand@6wind.com>]

On Fri, Feb 26, 2016 at 3:48 PM, Bruce Richardson
<bruce.richardson@intel.com> wrote:
> On Fri, Feb 26, 2016 at 09:24:06AM +0000, Wang, Xiao W wrote:
>> Hi,
>> > > Thanks for the discussion, Thomas, do you have any suggestions?
>> >
>> > I don't understand why you say this feature is specific to fm10k. Can we
>> > imagine another NIC having this capability?
>>
>> As you know, fm10k has a switch logic between the Mac and Phy, every packets
>> Sent out from the host will be switched inside the NIC, other NICs don't have
>> a switch inside, and the FTAG feature is related to the switch function.
>>
>> As introduced in the second patch:
>> The FM10K family of NICs support the addition of a Fabric Tag (FTAG) to carry
>> special information. The FTAG is placed at the beginning of the frame, it contains
>> information such as where the packet comes from and goes, and the vlan tag. In
>> FTAG based forwarding mode, the switch logic forwards packets according to
>> glort (global resource tag) information, rather than the mac and vlan table.
>> So this is a feature specific to fm10k.
>
> If it is fm10k specific, how about just adding a public function to the fm10k
> driver to turn it on. The user app will be non-portable across NICs, but
> that's the price of using nic-specific features.

What about using a devargs ?
Something like :
-w xxxx:xx:xx.x,enable_ftag=1

The application still needs to know about this to enable it, but that
sounds better to me.
The only issue is that it can't work with hotplug at the moment.


-- 
David Marchand