Re: [RFC] Add support for changing the flow ID of TCP connections

On 07/09/14 18:31, Navdeep Parhar wrote:
> On Wed, Jul 09, 2014 at 04:36:53PM +0200, Hans Petter Selasky wrote:
>> On 07/08/14 21:17, Navdeep Parhar wrote:
> ...
>>>
>>> I think we need to design this to be as generic as possible.  I have
>>> quite a bit of code that does this stuff but I haven't pushed it
>>> upstream or even offered it for review (yet).
>>>
>>
>> Hi,
>>
>> When will the non hardware related patches be available for review?
>> I understand there are multiple ways to reach the same goal, and I
>> think it would be great if we could agree on a common API for
>> applications.
>
> Here is the kernel side of the patch:
> http://people.freebsd.org/~np/flow_pacing_kern.diff
>
> The registration parameters and the throttling parameters are probably
> cxgbe-centric, because that's what it was written for.  We'll need to
> tidy up those structs certainly.  And I'd like to add pps constraints to
> the throttling parameters (all it does is bandwidth right now).

Hi Navdeep,

After reviewing your patch, we've concluded that we can't use your 
flow-ID API's AS-IS for the mlxen hardware. We are working on a new 
patch proposal after the feedback received here, and will probably post 
something in August, hence now it is vacation time and not all people 
are available.

Also we are worried that the m_tags cause un-needed overhead, that it 
invokes malloc for every pkt header duplication on transmit.

As to give you some clues: One of FreeBSD's targets is firewalls and 
routers. We think that a flow ID / hardware queue feature should also be 
usable by the firewall, and not only limited to TCP/UDP. That means you 
can create queues for multiple connections which then get rate limited 
as a firewall rule. Right now our main target is not the firewall, but 
we see that by minor modifications of the APIs, this feature becomes 
very easy to implement.

--HPS