From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753385Ab1ISOp6 (ORCPT ); Mon, 19 Sep 2011 10:45:58 -0400 Received: from mail.solarflare.com ([216.237.3.220]:1991 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751131Ab1ISOp4 (ORCPT ); Mon, 19 Sep 2011 10:45:56 -0400 Subject: Re: [net-next RFC V2 PATCH 0/5] Multiqueue support in tun/tap From: Ben Hutchings To: Jason Wang Cc: krkumar2@in.ibm.com, eric.dumazet@gmail.com, mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, davem@davemloft.net, kvm@vger.kernel.org, rusty@rustcorp.com.au, qemu-devel@nongnu.org, mirq-linux@rere.qmqm.pl, joe@perches.com, shemminger@vyatta.com In-Reply-To: <20110917055639.32666.89940.stgit@dhcp-91-7.nay.redhat.com.englab.nay.redhat.com> References: <20110917055639.32666.89940.stgit@dhcp-91-7.nay.redhat.com.englab.nay.redhat.com> Content-Type: text/plain; charset="UTF-8" Organization: Solarflare Communications Date: Mon, 19 Sep 2011 15:45:51 +0100 Message-ID: <1316443551.2764.9.camel@bwh-desktop> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 (2.32.2-1.fc14) Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 19 Sep 2011 14:45:56.0271 (UTC) FILETIME=[D6A0C3F0:01CC76DA] X-TM-AS-Product-Ver: SMEX-8.0.0.1181-6.500.1024-18394.005 X-TM-AS-Result: No--13.844600-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2011-09-17 at 14:02 +0800, Jason Wang wrote: [...] > 2 Current implementation may also get regression for single session > packet transmission. > > The reason is packets from each flow were not handled by the same > queue/vhost thread. > > Various method could be done to handle this: > > 2.1 hack the guest driver, and store the queue index into the rxhash and > use it when choosing tx in guest. This need some hack to store the > rxhash into sk and pass it in to skb again in > skb_orphan_try(). sk_rxhash is only used by RPS now, so some more > clean method is needed. [...] I have previously suggested doing this as a general rule. However, I now think we can do much better with accelerated RFS and automatic XPS (but the latter is not yet implemented). For virtio_net, accelerated RFS would effectively push the guest's RFS socket map out to the host. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.