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,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 11C61CA9EBD for ; Sat, 26 Oct 2019 05:47:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA231222CB for ; Sat, 26 Oct 2019 05:47:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726086AbfJZFrZ (ORCPT ); Sat, 26 Oct 2019 01:47:25 -0400 Received: from verein.lst.de ([213.95.11.211]:54267 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725939AbfJZFrZ (ORCPT ); Sat, 26 Oct 2019 01:47:25 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id CEFAB68B05; Sat, 26 Oct 2019 07:47:22 +0200 (CEST) Date: Sat, 26 Oct 2019 07:47:22 +0200 From: Christoph Hellwig To: Dave Chinner Cc: Eric Sandeen , Christoph Hellwig , linux-xfs@vger.kernel.org, Ian Kent Subject: Re: [PATCH 3/7] xfs: remove the m_readio_log field from struct xfs_mount Message-ID: <20191026054722.GA14648@lst.de> References: <20191025174026.31878-1-hch@lst.de> <20191025174026.31878-4-hch@lst.de> <851dcbf3-afbf-77fa-bd6e-3e1a8ccba7c7@sandeen.net> <20191025204329.GF4614@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191025204329.GF4614@dread.disaster.area> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Sat, Oct 26, 2019 at 07:43:29AM +1100, Dave Chinner wrote: > NFSv2 had a maximum client IO size of 8kB and writes were > synchronous. The Irix NFS server had some magic in it (enabled by > the filesystem wsync mount option) that allowed clients to have two > sequential 8k writes in flight at once, allowing XFS to optimise for > 16KB write IOs instead of the normal default of 64kB. This > optimisation was the reason that, at the time (early-mid 90s), SGI > machines had double the NFS write throughput of any other Unix > systems. > > I'm surprised we still support NFSv2 at all in this day and age - I > suspect we should just kill NFSv2 altogether. We need to keep the > wsync option around for HA systems serving files to NFS and CIFS > clients, but the 8kB IO size optimisations can certainly die.... Last time I talked to the NFS folks there still were some very obscure v2 use cases left (embedded devices that can't be upgraded). But yeah, I'll add a patch to stop overriding rsize/wsize with the sync option.