Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758106AbZKXWFe (ORCPT ); Tue, 24 Nov 2009 17:05:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757572AbZKXWFd (ORCPT ); Tue, 24 Nov 2009 17:05:33 -0500 Received: from mga02.intel.com ([134.134.136.20]:14603 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757216AbZKXWFc (ORCPT ); Tue, 24 Nov 2009 17:05:32 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.47,280,1257148800"; d="scan'208";a="470280311" Subject: Re: [PATCH v2] irq: Add node_affinity CPU masks for smarter irqbalance hints From: Peter P Waskiewicz Jr To: Thomas Gleixner Cc: David Miller , "linux-kernel@vger.kernel.org" , "arjan@linux.jf.intel.com" , "mingo@elte.hu" , "yong.zhang0@gmail.com" , "netdev@vger.kernel.org" In-Reply-To: References: <20091124093518.3909.16435.stgit@ppwaskie-hc2.jf.intel.com> <20091124.095703.107687163.davem@davemloft.net> Content-Type: text/plain Date: Tue, 24 Nov 2009 14:05:43 -0800 Message-Id: <1259100343.2631.78.camel@ppwaskie-mobl2> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1612 Lines: 41 On Tue, 2009-11-24 at 13:56 -0800, Thomas Gleixner wrote: > On Tue, 24 Nov 2009, David Miller wrote: > > > From: Thomas Gleixner > > Date: Tue, 24 Nov 2009 12:07:35 +0100 (CET) > > > > > And what does the kernel do with this information and why are we not > > > using the existing device/numa_node information ? > > > > It's a different problem space Thomas. > > > > If the device lives on NUMA node X, we still end up wanting to > > allocate memory resources (RX ring buffers) on other NUMA nodes on a > > per-queue basis. > > > > Otherwise a network card's forwarding performance is limited by the > > memory bandwidth of a single NUMA node, and on a multiqueue cards we > > therefore fare much better by allocating each device RX queue's memory > > resources on a different NUMA node. > > > > It is this NUMA usage that PJ is trying to export somehow to userspace > > so that irqbalanced and friends can choose the IRQ cpu masks more > > intelligently. > > So you need a preferred irq mask information on a per IRQ basis and > that mask is not restricted to the CPUs of a single NUMA node, right ? > Just to clarify, I need a preferred CPU mask on a per IRQ basis. And yes, that mask may not be restricted to the CPUs of a single NUMA node. But in the normal case, the mask will be restricted to CPUs of a single node. Cheers, -PJ -- 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/