Subject: Re: RDMA will be reverted

From: Evgeniy Polyakov <[email-masked]>
Date: Tue, 25 Jul 2006 11:42:30 +0400

On Tue, Jul 25, 2006 at 12:33:44AM -0700, David Miller ([email-masked]) wrote:
> From: Evgeniy Polyakov <[email-masked]>
> Date: Tue, 25 Jul 2006 10:59:21 +0400
> 
> > As a side completely unrelated to either my or others work note :) - 
> > I think it is a nanooptimisation - we get a bit of performance here, 
> > and lose those bit in other place.
> > When bag is filled, there is no much sence of rearranging some stuff
> > inside to be able to place another one - it is better to buy new bag.
> 
> It is a matter of what the viewpoint is, I suppose.

Definitely.

> I think in this specific case it might turn out to be
> better for the scheduler to respond to what the device
> throws at it, rather than the other way around.  And
> in that case we need no feedback from scheduler to
> cpu demux engine.

That's exactly one bit lose/gain - if CPU is loafing - we get a gain,
and lose otherwise - so instead of generally predictible steady behaviour 
we can end up with bursty shapes.

Actually without real tests all it is just a handwaving, so let's see when
modern NICs get that capability, so network softirq scheduling would be 
changed accordingly.

-- 
	Evgeniy Polyakov