From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752710AbcHLCwW (ORCPT ); Thu, 11 Aug 2016 22:52:22 -0400 Received: from verein.lst.de ([213.95.11.211]:44092 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752132AbcHLCwV (ORCPT ); Thu, 11 Aug 2016 22:52:21 -0400 Date: Fri, 12 Aug 2016 04:52:18 +0200 From: Christoph Hellwig To: Dave Chinner Cc: Linus Torvalds , Christoph Hellwig , "Huang, Ying" , LKML , Bob Peterson , Wu Fengguang , LKP Subject: Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Message-ID: <20160812025218.GB975@lst.de> References: <87eg5w18iu.fsf@yhuang-mobile.sh.intel.com> <87a8gk17x7.fsf@yhuang-mobile.sh.intel.com> <8760r816wf.fsf@yhuang-mobile.sh.intel.com> <20160811155721.GA23015@lst.de> <20160812005442.GN19025@dastard> <20160812022329.GP19025@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160812022329.GP19025@dastard> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 12, 2016 at 12:23:29PM +1000, Dave Chinner wrote: > Christoph, maybe there's something we can do to only trigger > speculative prealloc growth checks if the new file size crosses the end of > the currently allocated block at the EOF. That would chop out a fair > chunk of the xfs_bmapi_read calls being done in this workload. I'm > not sure how much effort we should spend optimising this slow path, > though.... I can look at that, but indeed optimizing this patch seems a bit stupid. The other thing we could do is to optimize xfs_bmapi_read - even if it shouldn't be called this often it seems like it should waste a whole lot less CPU cycles. From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============8694291245082560742==" MIME-Version: 1.0 From: Christoph Hellwig To: lkp@lists.01.org Subject: Re: [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Date: Fri, 12 Aug 2016 04:52:18 +0200 Message-ID: <20160812025218.GB975@lst.de> In-Reply-To: <20160812022329.GP19025@dastard> List-Id: --===============8694291245082560742== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Fri, Aug 12, 2016 at 12:23:29PM +1000, Dave Chinner wrote: > Christoph, maybe there's something we can do to only trigger > speculative prealloc growth checks if the new file size crosses the end of > the currently allocated block at the EOF. That would chop out a fair > chunk of the xfs_bmapi_read calls being done in this workload. I'm > not sure how much effort we should spend optimising this slow path, > though.... I can look at that, but indeed optimizing this patch seems a bit stupid. The other thing we could do is to optimize xfs_bmapi_read - even if it shouldn't be called this often it seems like it should waste a whole lot less CPU cycles. --===============8694291245082560742==--