From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: OFT - reserving CPU's for networking Date: Fri, 30 Apr 2010 21:58:52 +0200 (CEST) Message-ID: References: <1272563772.2222.301.camel@edumazet-laptop> <20100429111047.031eeff9@nehalam> <20100430.115715.216750975.davem@davemloft.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: shemminger@vyatta.com, eric.dumazet@gmail.com, ak@gargoyle.fritz.box, netdev@vger.kernel.org, andi@firstfloor.org, peterz@infradead.org To: David Miller Return-path: Received: from www.tglx.de ([62.245.132.106]:48610 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759302Ab0D3T7P (ORCPT ); Fri, 30 Apr 2010 15:59:15 -0400 In-Reply-To: <20100430.115715.216750975.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: Dave, On Fri, 30 Apr 2010, David Miller wrote: > From: Thomas Gleixner > Date: Thu, 29 Apr 2010 21:19:36 +0200 (CEST) > > > Aside of that I seriously doubt that you can do networking w/o time > > and timers. > > You're right that we need timestamps and the like. > > But only if we actually process the packets on these restricted cpus :-) > > If we use RPS and farm out all packets to other cpus, ie. just doing > the driver work and the remote cpu dispatch on these "offline" cpus, > it is doable. > > Then we can do cool tricks like having the cpu spin on a mwait() on the > network device's status descriptor in memory. > > In any event I agree with you, it's a cool idea at best, and likely > not really practical. Well, it might be worth to experiment with that once we get the basic infrastructure in place to "isolate" cores under full kernel control. It's not too hard to solve the problems, but it seems nobody has a free time slot to tackle them. Thanks tglx