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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 E087DC47247 for ; Tue, 5 May 2020 09:44:03 +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 ADD7920675 for ; Tue, 5 May 2020 09:44:03 +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="Jxs7X6uP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ADD7920675 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]:43804 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jVu7O-0007id-Tr for qemu-devel@archiver.kernel.org; Tue, 05 May 2020 05:44:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51456) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jVu6C-0006WT-2K for qemu-devel@nongnu.org; Tue, 05 May 2020 05:42:48 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:56181 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jVu6B-0005Gg-BH for qemu-devel@nongnu.org; Tue, 05 May 2020 05:42:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588671766; 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=Mho+gTo6qBUQMtEy/b5PsKdMhmjKyMojIIyYmCXoDgs=; b=Jxs7X6uPqUW1VGObn5upmoSG6gtN/XuEtgTxV15r2Uuvzv2PjMSEakUHMcKLclWqTeOa3T 0ZUI51T08GoXyVe13KslwuvOBV/lGpxhjX5ODh2yuGPufB6y044HG/SjhdWbqXSvVXKorb k/nFNGNK1rKDTDH6y7XniTostPxKLf4= 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-148-5ZDdjEEwO9imDaUH2RD9qA-1; Tue, 05 May 2020 05:42:43 -0400 X-MC-Unique: 5ZDdjEEwO9imDaUH2RD9qA-1 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 AB7A180183C; Tue, 5 May 2020 09:42:42 +0000 (UTC) Received: from linux.fritz.box (ovpn-112-11.ams2.redhat.com [10.36.112.11]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B1B7C600F5; Tue, 5 May 2020 09:42:41 +0000 (UTC) Date: Tue, 5 May 2020 11:42:40 +0200 From: Kevin Wolf To: qemu-block@nongnu.org Subject: Re: [PATCH 0/6] vmdk: Fix zero cluster handling Message-ID: <20200505094240.GG5759@linux.fritz.box> References: <20200430133007.170335-1-kwolf@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200430133007.170335-1-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Received-SPF: pass client-ip=205.139.110.61; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/05 00:37:40 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 30.04.2020 um 15:30 hat Kevin Wolf geschrieben: > What I was really investigating is why 055 was so slow. I couldn't solve > that, but instead I found out that our VMDK code for zero clusters and > write_zeroes was completely broken. Apart from segfaults when zero > clusters were actually enabled, this caused a compressed backup target > to result in a bigger file than uncompressed with VMDK. >=20 > This series tries to fix it (with one bonus performance patch). Thanks for the review, fixed up the commit messages and applied. If you were curious about the VMDK terminology, I looked it up and the basic terms translate to qcow2 like this: * grain directory =3D L1 table * grain table =3D L2 table * grain =3D cluster "zeroed-grain GTE (grain table entry)" is the exact term used in the VMDK spec for what we would call a zero cluster in qcow2. Kevin