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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 AEAEFC433E0 for ; Thu, 28 May 2020 22:59:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 852D020776 for ; Thu, 28 May 2020 22:59:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dfsiTZBY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437376AbgE1W7Q (ORCPT ); Thu, 28 May 2020 18:59:16 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:52270 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2437266AbgE1W7P (ORCPT ); Thu, 28 May 2020 18:59:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590706753; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Jzbxq2mlHqD0DlEQ0FYL4cGWSmL4FdNDgfV81d/7bRI=; b=dfsiTZBYxFM9DL8qPhK4xr+//JeRAVaPXt4188CBCkY3ga04w3zDkXZHGVqgCPPwijUXJu PU60TEX/bnCe/pl7Hn35pqCEXmayHukU1w8nJks5et4BHQjbFDr4ccicaYDNT7/Nw6SmYa Zx5ffUl8d0zRcqNOdR/XTg/Je30HERQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-111-sNEQlx0IOQOQbn7UfuparQ-1; Thu, 28 May 2020 18:59:11 -0400 X-MC-Unique: sNEQlx0IOQOQbn7UfuparQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 812C7107ACF4; Thu, 28 May 2020 22:59:09 +0000 (UTC) Received: from x1.home (ovpn-112-195.phx2.redhat.com [10.3.112.195]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4229C10013D0; Thu, 28 May 2020 22:59:07 +0000 (UTC) Date: Thu, 28 May 2020 16:59:06 -0600 From: Alex Williamson To: "Dr. David Alan Gilbert" Cc: Yan Zhao , 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: <20200528165906.7d03f689@x1.home> In-Reply-To: <20200527084822.GC3001@work-vm> 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> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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, Alex