Re: [PATCH v2] Receive Packet Steering

[Tom Herbert <therbert@google.com>]

On Mon, Jun 15, 2009 at 2:02 AM, David Miller<davem@davemloft.net> wrote:
> From: Tom Herbert <therbert@google.com>
> Date: Sun, 14 Jun 2009 22:52:13 -0700
>
>>> Just to keep this topic alive, I want to mention two things:
>>>
>>> 1) Just the other day support for the IXGBE "Flow Director" was
>>>   added to net-next-2.6, it basically does flow steering in
>>>   hardware.  It remembers where the last TX for a flow was
>>>   made, and steers RX traffic there.
>>>
>>
>> That's very cool.  Is this able to preserve in order delivery?
>
> I don't know how the hardware works to this level of detail,
> sorry.  But yet that's a very important issue.
>
>> What is the advantage over using a shared skbuff queue and making
>> doing a single IPI to schedule the backlog device on the remote CPU?
>
> No locking.  Queue is only ever accessed by the local cpu.
>

There's no lock to put the call_single_data structures onto remote
CPU's list?  Looking at generic_exec_single...