From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F7A7C433DF for ; Fri, 29 May 2020 04:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 840402074D for ; Fri, 29 May 2020 04:25:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728443AbgE2EZV (ORCPT ); Fri, 29 May 2020 00:25:21 -0400 Received: from mga03.intel.com ([134.134.136.65]:39685 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727811AbgE2EZR (ORCPT ); Fri, 29 May 2020 00:25:17 -0400 IronPort-SDR: YnmGchEwzcww1ijJDYeAp9MxNeSlM9w2VOxQW2h1WWYiar7G/y8vE/xIeXoMWxjconti4Mao65 bRwytFRGU3WA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2020 21:25:16 -0700 IronPort-SDR: LbimR6ujBCgASJuPZXnR+I9UPBzufB/aMJUq2aUy/HaeKwBGRfuKRCo7pz21sinVhhdMj1UGnA IJvBOc/sk6OA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,447,1583222400"; d="scan'208";a="414847654" Received: from joy-optiplex-7040.sh.intel.com (HELO joy-OptiPlex-7040) ([10.239.13.16]) by orsmga004.jf.intel.com with ESMTP; 28 May 2020 21:25:11 -0700 Date: Fri, 29 May 2020 00:15:17 -0400 From: Yan Zhao To: Alex Williamson Cc: "Dr. David Alan Gilbert" , Kirti Wankhede , cjia@nvidia.com, kevin.tian@intel.com, ziye.yang@intel.com, changpeng.liu@intel.com, yi.l.liu@intel.com, mlevitsk@redhat.com, eskultet@redhat.com, cohuck@redhat.com, jonathan.davies@nutanix.com, eauger@redhat.com, aik@ozlabs.ru, pasic@linux.ibm.com, felipe@nutanix.com, Zhengxiao.zx@alibaba-inc.com, shuangtai.tst@alibaba-inc.com, Ken.Xue@amd.com, zhi.a.wang@intel.com, qemu-devel@nongnu.org, kvm@vger.kernel.org Subject: Re: [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices Message-ID: <20200529041516.GE1378@joy-OptiPlex-7040> Reply-To: Yan Zhao References: <1589781397-28368-1-git-send-email-kwankhede@nvidia.com> <20200519105804.02f3cae8@x1.home> <20200525065925.GA698@joy-OptiPlex-7040> <426a5314-6d67-7cbe-bad0-e32f11d304ea@nvidia.com> <20200526141939.2632f100@x1.home> <20200527062358.GD19560@joy-OptiPlex-7040> <20200527084822.GC3001@work-vm> <20200528165906.7d03f689@x1.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200528165906.7d03f689@x1.home> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, May 28, 2020 at 04:59:06PM -0600, Alex Williamson wrote: > On Wed, 27 May 2020 09:48:22 +0100 > "Dr. David Alan Gilbert" wrote: > > * Yan Zhao (yan.y.zhao@intel.com) wrote: > > > BTW, for viommu, the downtime data is as below. under the same network > > > condition and guest memory size, and no running dirty data/memory produced > > > by device. > > > (1) viommu off > > > single-round dirty query: downtime ~100ms > > > > Fine. > > > > > (2) viommu on > > > single-round dirty query: downtime 58s > > > > Youch. > > Double Youch! But we believe this is because we're getting the dirty > bitmap one IOMMU leaf page at a time, right? We've enable the kernel > to get a dirty bitmap across multiple mappings, but QEMU isn't yet > taking advantage of it. Do I have this correct? Thanks, > Yes, I think so, but I haven't looked into it yet. Thanks Yan