From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pasi =?iso-8859-1?Q?K=E4rkk=E4inen?= Subject: Re: [Xen-devel] Re: [PATCH] xen network backend driver Date: Wed, 19 Jan 2011 21:28:23 +0200 Message-ID: <20110119192823.GN2754@reaktio.net> References: <1295449318.14981.3484.camel@zakaz.uk.xensource.com> <1295455216.11126.39.camel@bwh-desktop> <1295459316.14981.3727.camel@zakaz.uk.xensource.com> <1295460304.11126.53.camel@bwh-desktop> <4D3738AB.60701@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ben Hutchings , Ian Campbell , "netdev@vger.kernel.org" , xen-devel , Konrad Rzeszutek Wilk To: Jeremy Fitzhardinge Return-path: Received: from smtp.tele.fi ([192.89.123.25]:36120 "EHLO smtp.tele.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753814Ab1AST2n (ORCPT ); Wed, 19 Jan 2011 14:28:43 -0500 Content-Disposition: inline In-Reply-To: <4D3738AB.60701@goop.org> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jan 19, 2011 at 11:16:59AM -0800, Jeremy Fitzhardinge wrote: > On 01/19/2011 10:05 AM, Ben Hutchings wrote: > > Not in itself. NAPI polling will run on the same CPU which scheduled it > > (so wherever the IRQ was initially handled). If the protocol used > > between netfront and netback doesn't support RSS then RPS > > can be used to spread the RX work > > across CPUs. > > There's only one irq per netback which is bound to one (V)CPU at a > time. I guess we could extend it to have multiple irqs per netback and > some way of distributing packet flows over them, but that would only > really make sense if there's a single interface with much more traffic > than the others; otherwise the interrupts should be fairly well > distributed (assuming that the different netback irqs are routed to > different cpus). > Does "multiqueue" only work for NIC drivers (and frontend drivers), or could it be used also for netback? (afaik Linux multiqueue enables setting up multiple receive queues each having a separate irq.) -- Pasi