From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH v5] rfs: Receive Flow Steering Date: Fri, 16 Apr 2010 15:42:36 +0200 Message-ID: <20100416134236.GA18855@one.firstfloor.org> References: <87r5mf8va9.fsf@basil.nowhere.org> <1271424726.4606.42.camel@bigi> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , Tom Herbert , davem@davemloft.net, netdev@vger.kernel.org, eric.dumazet@gmail.com To: jamal Return-path: Received: from one.firstfloor.org ([213.235.205.2]:39759 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753120Ab0DPNmh (ORCPT ); Fri, 16 Apr 2010 09:42:37 -0400 Content-Disposition: inline In-Reply-To: <1271424726.4606.42.camel@bigi> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Apr 16, 2010 at 09:32:06AM -0400, jamal wrote: > How are you going to schedule the net softirq on an empty queue if you > do this? Sorry don't understand the question? You can always do the flow as if rps was not there. > BTW, in my tests sending an IPI to an SMT sibling or to another core > didnt make any difference in terms of latency - still 5 microsecs. > I dont have dual Nehalem where we have to cross QPI - there i suspect > it will be longer than 5 microsecs. I meant an IPI to a sibling is not useful. You send it to the IPI to get cache locality in the target, but if the target has the same cache locality as you you can as well avoid the cost of the IPI and process directly. For thread sibling I'm pretty sure it's useless. Not full sure about socket sibling. Maybe. -Andi -- ak@linux.intel.com -- Speaking for myself only.