From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932347AbcFNSYd (ORCPT ); Tue, 14 Jun 2016 14:24:33 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:36364 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932124AbcFNSYa (ORCPT ); Tue, 14 Jun 2016 14:24:30 -0400 Date: Tue, 14 Jun 2016 11:24:23 -0700 From: Christoph Hellwig To: Waiman Long Cc: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, linux-arch@vger.kernel.org, xfs@oss.sgi.com, Davidlohr Bueso , Jason Low , Dave Chinner , Scott J Norton , Douglas Hatch Subject: Re: [RFC PATCH-tip 6/6] xfs: Enable reader optimistic spinning for DAX inodes Message-ID: <20160614182423.GA6330@infradead.org> References: <1465927959-39719-1-git-send-email-Waiman.Long@hpe.com> <1465927959-39719-7-git-send-email-Waiman.Long@hpe.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1465927959-39719-7-git-send-email-Waiman.Long@hpe.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 14, 2016 at 02:12:39PM -0400, Waiman Long wrote: > This patch enables reader optimistic spinning for inodes that are > under a DAX-based mount point. > > On a 4-socket Haswell machine running on a 4.7-rc1 tip-based kernel, > the fio test with multithreaded randrw and randwrite tests on the > same file on a XFS partition on top of a NVDIMM with DAX were run, > the aggregated bandwidths before and after the patch were as follows: And why is this specific to DAX? Many I/O operations already never got out to disk, and ilock is mostly held for operations that have nothing to do with disk I/O.