Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753828AbaKMBV6 (ORCPT ); Wed, 12 Nov 2014 20:21:58 -0500 Received: from mga01.intel.com ([192.55.52.88]:35183 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753648AbaKMBVz (ORCPT ); Wed, 12 Nov 2014 20:21:55 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="415746520" From: "Zhang, Yang Z" To: "Wu, Feng" , Paolo Bonzini , "Alex Williamson" CC: "gleb@kernel.org" , "dwmw2@infradead.org" , "joro@8bytes.org" , "tglx@linutronix.de" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , "kvm@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH 05/13] KVM: Update IRTE according to guest interrupt configuration changes Thread-Topic: [PATCH 05/13] KVM: Update IRTE according to guest interrupt configuration changes Thread-Index: Ac/9kLfHSOSyagtOQAqEsc5J81STLgAyIb0DAAAcBYD//4ReAP/+e7+A//z07vA= Date: Thu, 13 Nov 2014 01:21:16 +0000 Message-ID: References: <5461EC99.1000101@redhat.com> <546324F4.8010002@redhat.com> <54632ECA.4070903@redhat.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id sAD1M1Nk020683 Wu, Feng wrote on 2014-11-13: > > > kvm-owner@vger.kernel.org wrote on 2014-11-12: >> kvm@vger.kernel.org; iommu@lists.linux-foundation.org; >> linux-kernel@vger.kernel.org >> Subject: Re: [PATCH 05/13] KVM: Update IRTE according to guest >> interrupt configuration changes >> >> >> >> On 12/11/2014 10:19, Wu, Feng wrote: >>>> You can certainly backport these patches to distros that do not >>>> have VFIO. But upstream we should work on VFIO first. VFIO has >>>> feature parity with legacy device assignment, and adding a new >>>> feature that is not in VFIO would be a bad idea. >>>> >>>> By the way, do you have benchmark results for it? We have not been >>>> able to see any performance improvement for APICv on e.g. netperf. >>> >>> Do you mean benchmark results for APICv itself or VT-d Posted-Interrtups? >> >> Especially for VT-d posted interrupts---but it'd be great to know >> which workloads see the biggest speedup from APICv. > > We have some draft performance data internally, please see the > attached. For VT-d PI, I think we can get the biggest performance gain > if the VCPU is running in non-root mode for most of the time (not in > HLT state), since external interrupt from assigned devices will be delivered by guest directly in this case. > That means we can run some cpu intensive workload in the guests. Have you check that the CPU side posted interrupt is taking effect in w/o VT-D PI case? Per my understanding, the performance gap should be so large if you use CPU side posted interrupt. This data more like the VT-d PI vs non PI(both VT-d and CPU). > > Thanks, > Feng > >> >> Paolo >> -- >> To unsubscribe from this list: send the line "unsubscribe kvm" in the >> body of a message to majordomo@vger.kernel.org More majordomo info at >> http://vger.kernel.org/majordomo-info.html Best regards, Yang ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?