From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Liu Subject: Re: [PATCH net-next 0/3] xen-netback: switch to NAPI + kthread 1:1 model Date: Wed, 28 Aug 2013 10:01:35 +0100 Message-ID: <20130828090135.GC15729@zion.uk.xensource.com> References: <1377518379-26503-1-git-send-email-wei.liu2@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: , , , , , Wei Liu To: Return-path: Received: from smtp.citrix.com ([66.165.176.89]:24177 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752482Ab3H1JBh (ORCPT ); Wed, 28 Aug 2013 05:01:37 -0400 Content-Disposition: inline In-Reply-To: <1377518379-26503-1-git-send-email-wei.liu2@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: Dave, ping. This series has been acked by maintainer. If there is no objection we would like to see it in. Thanks Wei. On Mon, Aug 26, 2013 at 12:59:36PM +0100, Wei Liu wrote: > This series implements NAPI + kthread 1:1 model for Xen netback. > > This model > - provides better scheduling fairness among vifs > - is prerequisite for implementing multiqueue for Xen network driver > > The second patch has the real meat: > - make use of NAPI to mitigate interrupt > - kthreads are not bound to CPUs any more, so that we can take > advantage of backend scheduler and trust it to do the right thing > > Benchmark is done on a Dell T3400 workstation with 4 cores, running 4 > DomUs. Netserver runs in Dom0. DomUs do netperf to Dom0 with > following command: /root/netperf -H Dom0 -fm -l120 > > IRQs are distributed to 4 cores by hand in the new model, while in the > old model vifs are automatically distributed to 4 kthreads. > > * New model > %Cpu0 : 0.5 us, 20.3 sy, 0.0 ni, 28.9 id, 0.0 wa, 0.0 hi, 24.4 si, 25.9 st > %Cpu1 : 0.5 us, 17.8 sy, 0.0 ni, 28.8 id, 0.0 wa, 0.0 hi, 27.7 si, 25.1 st > %Cpu2 : 0.5 us, 18.8 sy, 0.0 ni, 30.7 id, 0.0 wa, 0.0 hi, 22.9 si, 27.1 st > %Cpu3 : 0.0 us, 20.1 sy, 0.0 ni, 30.4 id, 0.0 wa, 0.0 hi, 22.7 si, 26.8 st > Throughputs: 2027.89 2025.95 2018.57 2016.23 aggregated: 8088.64 > > * Old model > %Cpu0 : 0.5 us, 68.8 sy, 0.0 ni, 16.1 id, 0.5 wa, 0.0 hi, 2.8 si, 11.5 st > %Cpu1 : 0.4 us, 45.1 sy, 0.0 ni, 31.1 id, 0.4 wa, 0.0 hi, 2.1 si, 20.9 st > %Cpu2 : 0.9 us, 44.8 sy, 0.0 ni, 30.9 id, 0.0 wa, 0.0 hi, 1.3 si, 22.2 st > %Cpu3 : 0.8 us, 46.4 sy, 0.0 ni, 28.3 id, 1.3 wa, 0.0 hi, 2.1 si, 21.1 st > Throughputs: 1899.14 2280.43 1963.33 1893.47 aggregated: 8036.37 > > We can see that the impact is mainly on CPU usage. The new model moves > processing from kthread to NAPI (software interrupt). > > Wei Liu (3): > xen-netback: remove page tracking facility > xen-netback: switch to NAPI + kthread 1:1 model > xen-netback: rename functions > > drivers/net/xen-netback/common.h | 150 +++++-- > drivers/net/xen-netback/interface.c | 135 ++++-- > drivers/net/xen-netback/netback.c | 833 +++++++++++------------------------ > 3 files changed, 445 insertions(+), 673 deletions(-) > > -- > 1.7.10.4