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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 022B9C5DF60 for ; Thu, 7 Nov 2019 12:07:16 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C26842166E for ; Thu, 7 Nov 2019 12:07:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dhGtR/pP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C26842166E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:41418 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSgZG-0001De-Vq for qemu-devel@archiver.kernel.org; Thu, 07 Nov 2019 07:07:15 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54541) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSgYa-0000m8-V1 for qemu-devel@nongnu.org; Thu, 07 Nov 2019 07:06:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iSgYZ-0007yO-Lc for qemu-devel@nongnu.org; Thu, 07 Nov 2019 07:06:32 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:22257 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iSgYZ-0007xa-HH for qemu-devel@nongnu.org; Thu, 07 Nov 2019 07:06:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573128390; 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=ULS/1IjXgMgTDoFigmjL1mRWRO1ML6pOTSfDWBeiZxc=; b=dhGtR/pPF6PJfEiRw3Io5X6//43sEfJ9CiIKvvSxd10LmF9go6lo1WnKNF1Jq+dW+5RDCS 0v6GoIyUCBtc8sJp9ZF7ePbChmk0ZZu/UbaWD4KnjttcY7HBlWHVx0DKb6TZfU5NSxF0uo uMfSlc2nMq00fNwpzqvVPl7dewa89fE= 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-128-0Dcb6QUzMVq-VyvXekDusQ-1; Thu, 07 Nov 2019 07:06:27 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DDF021800D7A; Thu, 7 Nov 2019 12:06:26 +0000 (UTC) Received: from work-vm (unknown [10.36.118.14]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 09D4C600D3; Thu, 7 Nov 2019 12:06:25 +0000 (UTC) Date: Thu, 7 Nov 2019 12:06:23 +0000 From: "Dr. David Alan Gilbert" To: Wei Yang Subject: Re: [PATCH 0/6] migration/postcopy: enable compress during postcopy Message-ID: <20191107120623.GH2816@work-vm> References: <20191018004850.9888-1-richardw.yang@linux.intel.com> <20191106201144.GM2802@work-vm> <20191107060210.GB13394@richard> <20191107091544.GB2816@work-vm> <20191107120332.GA25593@richard> MIME-Version: 1.0 In-Reply-To: <20191107120332.GA25593@richard> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: 0Dcb6QUzMVq-VyvXekDusQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > On Thu, Nov 07, 2019 at 09:15:44AM +0000, Dr. David Alan Gilbert wrote: > >* Wei Yang (richardw.yang@linux.intel.com) wrote: > >> On Wed, Nov 06, 2019 at 08:11:44PM +0000, Dr. David Alan Gilbert wrote= : > >> >* Wei Yang (richardw.yang@linux.intel.com) wrote: > >> >> This patch set tries enable compress during postcopy. > >> >>=20 > >> >> postcopy requires to place a whole host page, while migration threa= d migrate > >> >> memory in target page size. This makes postcopy need to collect all= target > >> >> pages in one host page before placing via userfaultfd. > >> >>=20 > >> >> To enable compress during postcopy, there are two problems to solve= : > >> >>=20 > >> >> 1. Random order for target page arrival > >> >> 2. Target pages in one host page arrives without interrupt by t= arget > >> >> page from other host page > >> >>=20 > >> >> The first one is handled by counting the number of target pages arr= ived > >> >> instead of the last target page arrived. > >> >>=20 > >> >> The second one is handled by: > >> >>=20 > >> >> 1. Flush compress thread for each host page > >> >> 2. Wait for decompress thread for before placing host page > >> >>=20 > >> >> With the combination of these two changes, compress is enabled duri= ng > >> >> postcopy. > >> > > >> >What have you tested this with? 2MB huge pages I guess? > >> > > >>=20 > >> I tried with this qemu option: > >>=20 > >> -object memory-backend-file,id=3Dmem1,mem-path=3D/dev/hugepages/gue= st2,size=3D4G \ > >> -device pc-dimm,id=3Ddimm1,memdev=3Dmem1 > >>=20 > >> /dev/hugepages/guest2 is a file under hugetlbfs > >>=20 > >> hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,pagesize=3D= 2M) > > > >OK, yes that should be fine. > >I suspect on Power/ARM where they have normal memory with 16/64k pages, > >the cost of the flush will mean compression is more expensive in > >postcopy mode; but still makes it possible. > > >=20 > Not get your point clearly about more expensive. You mean more expensive = on > ARM/Power? Yes; you're doing a flush at the end of each host page; on x86 without hugepages you don't do anything, on arm/power you'll need to do a flush at the end of each of their normal pages - so that's a bit more expensive. > If the solution looks good to you, I would prepare v2. Yes; I think it is OK. Dave > >Dave > > > >> >Dave > >> > > >> >> Wei Yang (6): > >> >> migration/postcopy: reduce memset when it is zero page and > >> >> matches_target_page_size > >> >> migration/postcopy: wait for decompress thread in precopy > >> >> migration/postcopy: count target page number to decide the > >> >> place_needed > >> >> migration/postcopy: set all_zero to true on the first target page > >> >> migration/postcopy: enable random order target page arrival > >> >> migration/postcopy: enable compress during postcopy > >> >>=20 > >> >> migration/migration.c | 11 -------- > >> >> migration/ram.c | 65 ++++++++++++++++++++++++++++++---------= ---- > >> >> 2 files changed, 45 insertions(+), 31 deletions(-) > >> >>=20 > >> >> --=20 > >> >> 2.17.1 > >> >>=20 > >> >-- > >> >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > >>=20 > >> --=20 > >> Wei Yang > >> Help you, Help me > >-- > >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >=20 > --=20 > Wei Yang > Help you, Help me -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK