Re: [net-next PATCH v3 3/8] net: sched: add cls_u32 offload hooks for netdevs

On Thu, Feb 18, 2016 at 11:23 AM, Amir Vadai" [off-list ref] wrote:

On Wed, Feb 17, 2016 at 03:07:23PM -0800, John Fastabend wrote:

quoted

Actually thinking about this a bit more I wrote this thinking
that there existed some hardware that actually cared if it was
a new rule or an existing rule. For me it doesn't matter I do
the same thing in the new/replace cases I just write into the
slot on the hardware table and if it happens to have something
in it well its overwritten e.g. "replaced". This works because
the cls_u32 layer protects us from doing something unexpected.

quoted

I'm wondering (mostly asking the mlx folks) is there hardware
out there that cares to make this distinction between new and
replace? Otherwise I can just drop new and always use replace.
Or vice versa which is the case in its current form.

I don't see a need for such a distinction in mlx hardware.

If you (say) have the same match and different action for a given rule
we have HW API to modify existing steering entry under which we would
end up calling the FW once instead of twice (delete old, add new).

Or.