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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 EFE6AC43334 for ; Thu, 6 Sep 2018 12:58:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFA8220844 for ; Thu, 6 Sep 2018 12:58:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AFA8220844 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728770AbeIFReJ (ORCPT ); Thu, 6 Sep 2018 13:34:09 -0400 Received: from outbound-smtp10.blacknight.com ([46.22.139.15]:33725 "EHLO outbound-smtp10.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728758AbeIFReJ (ORCPT ); Thu, 6 Sep 2018 13:34:09 -0400 Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp10.blacknight.com (Postfix) with ESMTPS id 2A29C1C1EDF for ; Thu, 6 Sep 2018 13:58:45 +0100 (IST) Received: (qmail 13244 invoked from network); 6 Sep 2018 12:58:45 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[37.228.229.88]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 6 Sep 2018 12:58:45 -0000 Date: Thu, 6 Sep 2018 13:58:43 +0100 From: Mel Gorman To: Jirka Hladky Cc: Kamil Kolakowski , Jakub Racek , linux-kernel , "Rafael J. Wysocki" , Len Brown , linux-acpi@vger.kernel.org Subject: Re: [4.17 regression] Performance drop on kernel-4.17 visible on Stream, Linpack and NAS parallel benchmarks Message-ID: <20180906125843.GC1719@techsingularity.net> References: <20180717100329.yfy7igdsrpk5ujf4@techsingularity.net> <20180904090053.GB1719@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 06, 2018 at 10:16:28AM +0200, Jirka Hladky wrote: > Hi Mel, > > we have results with 2d4056fafa196e1ab4e7161bae4df76f9602d56d reverted. > > * Compared to 4.18, there is still performance regression - > especially with NAS (sp_C_x subtest) and SPECjvm2008. On 4 NUMA > systems, regression is around 10-15% > * Compared to 4.19rc1 there is a clear gain across all benchmarks around 20% > Ok. > While reverting 2d4056fafa196e1ab4e7161bae4df76f9602d56d has helped a > lot there is another issue as well. Could you please recommend some > commit prior to 2d4056fafa196e1ab4e7161bae4df76f9602d56d to try? > Maybe 305c1fac3225dfa7eeb89bfe91b7335a6edd5172. That introduces a weird condition in terms of idle CPU handling that has been problematic. > Regarding the current results, how do we proceed? Could you please > contact Srikar and ask for the advice or should we contact him > directly? > I would suggest contacting Srikar directly. While I'm working on a series that touches off some similar areas, there is no guarantee it'll be a success as I'm not primarily upstream focused at the moment. Restarting the thread would also end up with a much more sensible cc list. -- Mel Gorman SUSE Labs