From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: why all packets have same queue no when rps enabled? Date: Tue, 22 Feb 2011 12:45:56 +0000 Message-ID: <1298378756.2211.478.camel@localhost> References: <4A6A2125329CFD4D8CC40C9E8ABCAB9F24D3DE6D0C@MILEXCH2.ds.jdsu.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "netdev@vger.kernel.org" To: Jon Zhou Return-path: Received: from exchange.solarflare.com ([216.237.3.220]:2097 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751351Ab1BVMqA (ORCPT ); Tue, 22 Feb 2011 07:46:00 -0500 In-Reply-To: <4A6A2125329CFD4D8CC40C9E8ABCAB9F24D3DE6D0C@MILEXCH2.ds.jdsu.net> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2011-02-21 at 20:07 -0800, Jon Zhou wrote: > Hi > > I expect each incoming packet will have a different queue no. when I > enabled RPS on kernel 2.6.36.4 [...] > Looks almost all packets fall at same queue? > Will RPS allocate queue no for each packet? and what hash algorithm > rps used? (is it Toeplitz hash algorithm?) The queue number identifies a hardware queue. RPS therefore does not update this number when queueing packets for processing on other CPUs. If the hardware/driver provides a receive hash (probably Toeplitz) then this is used for RPS. Otherwise a much cheaper hash is used. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.