Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763116AbZCNAxo (ORCPT ); Fri, 13 Mar 2009 20:53:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756496AbZCNAYS (ORCPT ); Fri, 13 Mar 2009 20:24:18 -0400 Received: from smtp-out.google.com ([216.239.33.17]:1925 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757858AbZCNAYQ (ORCPT ); Fri, 13 Mar 2009 20:24:16 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:in-reply-to:references:date:message-id:subject:from:to: cc:content-type:content-transfer-encoding:x-system-of-record; b=S+3MTkAHSjWs15L5rEifNIurhwcuDZbzJuWAtW2zk700vthsnjutI/hnC0GqgxV8i 6/08aIRDAO+DEivDCLXEg== MIME-Version: 1.0 In-Reply-To: <20090313.151913.21135937.davem@davemloft.net> References: <65634d660903131358h765bef64y6a0f1b0db7400f6f@mail.gmail.com> <20090313.140217.143696945.davem@davemloft.net> <65634d660903131459m645eb468y3ad850a1fd56d447@mail.gmail.com> <20090313.151913.21135937.davem@davemloft.net> Date: Fri, 13 Mar 2009 17:24:10 -0700 Message-ID: <65634d660903131724s49009177pdc11005aa76a4b56@mail.gmail.com> Subject: Re: [RFC v2: Patch 1/3] net: hand off skb list to other cpu to submit to upper layer From: Tom Herbert To: David Miller Cc: yanmin_zhang@linux.intel.com, bhutchings@solarflare.com, andi@firstfloor.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, herbert@gondor.apana.org.au, jesse.brandeburg@intel.com, shemminger@vyatta.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1440 Lines: 30 >> I appreciate this philosophy, but unfortunately I don't have the >> luxury of working with a NIC that solves these problems. The reality >> may be that we're trying to squeeze performance out of crappy hardware >> to scale on multi-core. Left alone we couldn't get the stack to >> scale, but with these "destable hacks" we've gotten 3X or so > ^^^^^^^^ > > Spelling. > >> improvement in packets per second across both our dumb 1G and 10G >> NICs > > Do these NICs at least support multiqueue? > Yes, we are using a 10G NIC that supports multi-queue. The number of RX queues supported is half the number of cores on our platform, so that is going to limit the parallelism. With multi-queue turned on we do see about 4X improvement in pps over just using a single queue; this is about the same improvement we see using a single queue with our software steering techniques (this particular device provides the Toeplitz hash). Enabling HW multi-queue has somewhat higher CPU utilization though, the extra device interrupt load is not coming for free. We actually use the HW multi-queue in conjunction with our software steering to get maximum pps (about 20% more). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/