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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 4582DC433E3 for ; Wed, 19 Aug 2020 10:49:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 269C72076E for ; Wed, 19 Aug 2020 10:49:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728033AbgHSKtZ (ORCPT ); Wed, 19 Aug 2020 06:49:25 -0400 Received: from verein.lst.de ([213.95.11.211]:37194 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727019AbgHSKtT (ORCPT ); Wed, 19 Aug 2020 06:49:19 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 2F14E68BEB; Wed, 19 Aug 2020 12:49:16 +0200 (CEST) Date: Wed, 19 Aug 2020 12:49:15 +0200 From: Christoph Hellwig To: Javier Gonzalez Cc: Christoph Hellwig , Kanchan Joshi , kbusch@kernel.org, Damien.LeMoal@wdc.com, axboe@kernel.dk, sagi@grimberg.me, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, johannes.thumshirn@wdc.com, Nitesh Shetty , SelvaKumar S Subject: Re: [PATCH 2/2] nvme: add emulation for zone-append Message-ID: <20200819104915.GA3153@lst.de> References: <20200818052936.10995-1-joshi.k@samsung.com> <20200818052936.10995-3-joshi.k@samsung.com> <20200818071249.GB2544@lst.de> <20200818095033.h6ybdwiq3ljagl5a@mpHalley.local> <20200818155004.GA26688@lst.de> <20200818180428.obipue6adpqqpwjj@MacBook-Pro.localdomain> <20200819074035.GA21991@lst.de> <20200819083353.rwblagiesocfcq7i@mpHalley.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200819083353.rwblagiesocfcq7i@mpHalley.local> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 19, 2020 at 10:33:53AM +0200, Javier Gonzalez wrote: > I would ask you to reconsider this position. I have a hard time > understanding how zone append emulation is a good idea in SCSI and not > in NVMe, when there is no performance penalty. Per the numbers on btrfs and zonefs numbers zone append emulation is faster than using serialized writes, but also way slower than native zone append. Zone append emulation for SCSI is the way to bring support for pre-existing standards into the brave new world. Not requiring Zone Append in a standard designed around it because of bowing down to last minute political interventions in the standards committee is shooting ourselves in the foot.