On Fri, Feb 26, 2016 at 3:48 PM, Bruce Richardson
[off-list ref] wrote:

On Fri, Feb 26, 2016 at 09:24:06AM +0000, Wang, Xiao W wrote:

quoted

Hi,

quoted

quoted

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