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=-2.5 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 1E88EC00307 for ; Mon, 9 Sep 2019 05:32:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F20202196E for ; Mon, 9 Sep 2019 05:32:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726768AbfIIFcr (ORCPT ); Mon, 9 Sep 2019 01:32:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45852 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726646AbfIIFcr (ORCPT ); Mon, 9 Sep 2019 01:32:47 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DAF6610C092E; Mon, 9 Sep 2019 05:32:46 +0000 (UTC) Received: from rh (ovpn-116-55.phx2.redhat.com [10.3.116.55]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 80BA45C1D8; Mon, 9 Sep 2019 05:32:46 +0000 (UTC) Received: from [::1] (helo=rh) by rh with esmtps (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1i7CI4-0001qw-3g; Mon, 09 Sep 2019 15:32:40 +1000 Date: Mon, 9 Sep 2019 15:32:36 +1000 From: Dave Chinner To: kernel test robot Cc: "Darrick J. Wong" , Christoph Hellwig , LKML , linux-xfs@vger.kernel.org, lkp@01.org Subject: Re: [xfs] 610125ab1e: fsmark.app_overhead -71.2% improvement Message-ID: <20190909053236.GP2254@rh> References: <20190909015849.GN15734@shao2-debian> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190909015849.GN15734@shao2-debian> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.66]); Mon, 09 Sep 2019 05:32:47 +0000 (UTC) Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Sep 09, 2019 at 09:58:49AM +0800, kernel test robot wrote: > Greeting, > > FYI, we noticed a -71.2% improvement of fsmark.app_overhead due to commit: A negative improvement? That's somewhat ambiguous... > 0e822255f95db400 610125ab1e4b1b48dcffe74d9d8 > ---------------- --------------------------- > %stddev %change %stddev > \ | \ > 1.095e+08 -71.2% 31557568 fsmark.app_overhead > 6157 +95.5% 12034 fsmark.files_per_sec So, the files/s rate doubled, and the amount of time spent in userspace by the fsmark app dropped by 70%. > 167.31 -47.3% 88.25 fsmark.time.elapsed_time > 167.31 -47.3% 88.25 fsmark.time.elapsed_time.max Wall time went down by 50%. > 91.00 -8.8% 83.00 fsmark.time.percent_of_cpu_this_job_got > 148.15 -53.2% 69.38 fsmark.time.system_time As did system CPU. IOWs, this change has changed create performance by a factor of 4 - the file create is 2x faster for half the CPU spent. I don't think this is a negative improvement - it's a large positive improvement. I suspect that you need to change the metric classifications for this workload... Cheers, Dave. -- Dave Chinner dchinner@redhat.com