From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: RDMA will be reverted Date: Tue, 25 Jul 2006 11:42:30 +0400 Message-ID: <20060725074226.GA16682@2ka.mipt.ru> References: <20060725055127.GA5103@2ka.mipt.ru> <20060724.234853.112197982.davem@davemloft.net> <20060725065921.GB30561@2ka.mipt.ru> <20060725.003344.125313848.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Cc: rdreier@cisco.com, ak@suse.de, tom@opengridcomputing.com, netdev@vger.kernel.org, akpm@osdl.org Return-path: Received: from relay.2ka.mipt.ru ([194.85.82.65]:7308 "EHLO 2ka.mipt.ru") by vger.kernel.org with ESMTP id S1751454AbWGYHqu (ORCPT ); Tue, 25 Jul 2006 03:46:50 -0400 To: David Miller Content-Disposition: inline In-Reply-To: <20060725.003344.125313848.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Jul 25, 2006 at 12:33:44AM -0700, David Miller (davem@davemloft.net) wrote: > From: Evgeniy Polyakov > 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