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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 0E8ECC433FF for ; Tue, 6 Aug 2019 08:04:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6F1620665 for ; Tue, 6 Aug 2019 08:04:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565078659; bh=3Ab6azwCRUApXjTtOp3xXdwO+6wkC3I4KWyYZfWn8PU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=HER/OYIi3LmqX5JaQwMsDCGA6xlqF+R8XBX4M1V6xuCtjbLZHcRUj1YQ2LpLwumdq xykKkSl5Y8O84yqj9J8Tev7gEzXaA7nxAjcksKpRC4C9o+2xT754BvTrLinBkb8btY GwUbOLaKLB+++Dp37Zt4bB+PU990iUl8x8WlwqMQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732217AbfHFIES (ORCPT ); Tue, 6 Aug 2019 04:04:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:46518 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728843AbfHFIES (ORCPT ); Tue, 6 Aug 2019 04:04:18 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 3B33EAF1D; Tue, 6 Aug 2019 08:04:17 +0000 (UTC) Date: Tue, 6 Aug 2019 10:04:15 +0200 From: Michal Hocko To: kernel test robot Cc: Minchan Kim , Andrew Morton , LKML , linux-mm , Miguel de Dios , Wei Wang , Johannes Weiner , Mel Gorman , lkp@01.org Subject: Re: [mm] 755d6edc1a: will-it-scale.per_process_ops -4.1% regression Message-ID: <20190806080415.GG11812@dhcp22.suse.cz> References: <20190729071037.241581-1-minchan@kernel.org> <20190806070547.GA10123@xsang-OptiPlex-9020> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190806070547.GA10123@xsang-OptiPlex-9020> 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 Tue 06-08-19 15:05:47, kernel test robot wrote: > Greeting, > > FYI, we noticed a -4.1% regression of will-it-scale.per_process_ops due to commit: I have to confess I cannot make much sense from numbers because they seem to be too volatile and the main contributor doesn't stand up for me. Anyway, regressions on microbenchmarks like this are not all that surprising when a locking is slightly changed and the critical section made shorter. I have seen that in the past already. That being said I would still love to get to bottom of this bug rather than play with the lock duration by a magic. In other words http://lkml.kernel.org/r/20190730125751.GS9330@dhcp22.suse.cz -- Michal Hocko SUSE Labs