From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932188AbeCKNCH (ORCPT ); Sun, 11 Mar 2018 09:02:07 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56620 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932129AbeCKNCF (ORCPT ); Sun, 11 Mar 2018 09:02:05 -0400 To: LKML , Mike Snitzer , Mikulas Patocka , Alasdair G Kergon , viro@zeniv.linux.org.uk From: Zdenek Kabelac Subject: Timing performance regression 4.15 to 4.16-rc1 Organization: Red Hat Message-ID: <31a4b0d7-2c9e-ce76-a486-48ed18b96cc6@redhat.com> Date: Sun, 11 Mar 2018 14:02:03 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi I've noticed quite some drop of performance (around 15% in some cases) where execution of lvm2 tests took longer time - and while tests itself should not really load CPU system - the overall running time just got bigger. Running bisect game pointed clearly to this commit: --- commit 44c02a2c3dc55835e9f0d8ef73966406cd805001 Author: Al Viro Date: Thu Oct 5 12:59:44 2017 -0400 dev_ioctl(): move copyin/copyout to callers --- clear revert of this commit on top of 3266b5bd97eaa72793df0b6e5a106c69ccc166c4 (recent ~4.16-rc4) restored timing of tests back. I'm not sure why - so at this moment this is just a patch causing 15% longer running times on lvm2 test suite. Regards Zdenek