From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752360AbdGGUza (ORCPT ); Fri, 7 Jul 2017 16:55:30 -0400 Received: from mail-oi0-f67.google.com ([209.85.218.67]:32831 "EHLO mail-oi0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751059AbdGGUz3 (ORCPT ); Fri, 7 Jul 2017 16:55:29 -0400 MIME-Version: 1.0 In-Reply-To: <20170705164850.lnziwloc6mko3mxo@hirez.programming.kicks-ass.net> References: <20170705164850.lnziwloc6mko3mxo@hirez.programming.kicks-ass.net> From: Ben Guthro Date: Fri, 7 Jul 2017 16:55:27 -0400 X-Google-Sender-Auth: hiKSPNCsAYhhMsuPRI-Z1LgBtcA Message-ID: Subject: Re: Potential scheduler regression To: Peter Zijlstra Cc: Linux Kernel Mailing List , Linus Torvalds , Mike Galbraith , Thomas Gleixner , Ingo Molnar Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 5, 2017 at 12:48 PM, Peter Zijlstra wrote: > On Wed, Jul 05, 2017 at 11:42:46AM -0400, Ben Guthro wrote: >> Hello, >> >> I've been in the process of updating our kernel in our appliance VM >> from an old LTS kernel (4.1.y) to something a bit more modern (4.9.y) >> - and ran into a performance regression, when our QA team was running >> some regression suites. >> >> >> I bisect this behavior to the following commit, introduced in the 4.9 >> merge window: >> > > Could you test a later kernel that includes commit: > > 1ad3aaf3fcd2 ("sched/core: Implement new approach to scale select_idle_cpu()") > (resend without html) Apologies on the delay - it took a bit to get the machines, to run the test. I am happy to report that the kernel at 1ad3aaf3fcd2, seems to regain performance loss from 1b568f0aab, in our test environment. Since 4.9 is an LTS kernel - is this appropriate to suggest to be included in the linux-stable list?