From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751308AbdIMEcR (ORCPT ); Wed, 13 Sep 2017 00:32:17 -0400 Received: from shells.gnugeneration.com ([66.240.222.126]:41224 "EHLO shells.gnugeneration.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728AbdIMEcO (ORCPT ); Wed, 13 Sep 2017 00:32:14 -0400 X-Greylist: delayed 449 seconds by postgrey-1.27 at vger.kernel.org; Wed, 13 Sep 2017 00:32:14 EDT Date: Tue, 12 Sep 2017 21:29:38 -0700 From: vcaputo@pengaru.com To: linux-kernel Subject: Seemingly random performance degradation in 4.13 Message-ID: <20170913042938.GY9731@shells.gnugeneration.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, I've been working on some graphics hacks which has me paying close attention to frame rates. Something I've noticed recently in the 4.13 cycle is a seemingly random loss of ~40% frame rate. These are purely software-rendered hacks, and I haven't spent much time trying to figure out what is changing when the performance drops - typically the performance is restored on a subsequent boot. There's been talk of NUMA and scheduler related performance regressions, and I'm wondering if that's related to what I'm observing. Is there a fix floating around I can apply and see if it prevents regressions from occurring? FYI the machine in question is a 1.8Ghz core2 duo thinkpad x61s, currently on 4.13-rc7. If there's anything in particular that would be useful for me to capture when running one of these tests, a specific perf incantation for example, I'm happy to test and report the results. Cheers, Vito Caputo