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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE392FA3742 for ; Fri, 28 Oct 2022 18:15:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230193AbiJ1SPt (ORCPT ); Fri, 28 Oct 2022 14:15:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230029AbiJ1SPs (ORCPT ); Fri, 28 Oct 2022 14:15:48 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 501121DF433; Fri, 28 Oct 2022 11:15:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ZlI2chvRYb2y9PurSe5IwUlJzWP/UEWczmRM1gvoFUQ=; b=JGUnpCk9FYA0l0ezvRgHDZ2hy4 2tNXDVQ5LJZwSEV0qCn1nBnxmC3h9Z61+miYSFLoSIPLczoznJ1LUg+uJOmzqoLtY6M3cFIbjOZMn La7gL6YJRrzJAaK4ZQkTDbPIE7lozSx/gPnZYnfDuZalpOc3HODFTbx+pj4YyTJuZV7BNg6g/h1/n 2ny91/mPyWrcjLh1RotU3CEjNv/XWH+p4s/ebsflwNTDraZybo5JWRXP8ymQnBBiyDDVQySfGF8F6 WyG1yvYffLjK7ysxrtS+gcPfzbHqgxvl+oqWcPy/pea+lRg3IyCzQsMfMasytbkQZl+5Tjol2pMWi ht7frLtA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1ooTtN-001RbN-61; Fri, 28 Oct 2022 18:15:41 +0000 Date: Fri, 28 Oct 2022 19:15:41 +0100 From: Matthew Wilcox To: "Darrick J. Wong" Cc: "Ritesh Harjani (IBM)" , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , Aravinda Herle Subject: Re: [RFC 2/2] iomap: Support subpage size dirty tracking to improve write performance Message-ID: References: <886076cfa6f547d22765c522177d33cf621013d2.1666928993.git.ritesh.list@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Oct 28, 2022 at 10:01:19AM -0700, Darrick J. Wong wrote: > On Fri, Oct 28, 2022 at 10:00:33AM +0530, Ritesh Harjani (IBM) wrote: > > Performance testing of below fio workload reveals ~16x performance > > improvement on nvme with XFS (4k blocksize) on Power (64K pagesize) > > FIO reported write bw scores improved from around ~28 MBps to ~452 MBps. > > > > > > [global] > > ioengine=psync > > rw=randwrite > > overwrite=1 > > pre_read=1 > > direct=0 > > bs=4k > > size=1G > > dir=./ > > numjobs=8 > > fdatasync=1 > > runtime=60 > > iodepth=64 > > group_reporting=1 > > Admittedly I'm not thrilled at the reintroduction of page and iop dirty > state that are updated in separate places, but OTOH the write > amplification here is demonstrably horrifying as you point out so it's > clearly necessary. Well, *something* is necessary. I worked on a different approach that would have similar effects for this exact workload, which was to submit the I/O for O_SYNC while we still know which part of the page we dirtied. Previous discussion: https://lore.kernel.org/all/YQlgjh2R8OzJkFoB@casper.infradead.org/ Actual patches: https://lore.kernel.org/all/20220503064008.3682332-1-willy@infradead.org/