Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751199AbdIFFOC (ORCPT ); Wed, 6 Sep 2017 01:14:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:37030 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750752AbdIFFOB (ORCPT ); Wed, 6 Sep 2017 01:14:01 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9C1A821BF5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org X-Google-Smtp-Source: ADKCNb6/QatFn44DEGRzwx1kwy9A7GtZU41c6Q4YsmFc2MKCLsnbN1AIyUQCY7g8gS14/VdEPvFq602gYDmcTfGlx5E= MIME-Version: 1.0 From: Andy Lutomirski Date: Tue, 5 Sep 2017 22:13:39 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Abysmal scheduler performance in Linus' tree? To: Ingo Molnar , Peter Zijlstra , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 625 Lines: 12 I'm running e7d0c41ecc2e372a81741a30894f556afec24315 from Linus' tree today, and I'm seeing abysmal scheduler performance. Running make -j4 ends up with all the tasks on CPU 3 most of the time (on my 4-logical-thread laptop). taskset -c 0 whatever puts whatever on CPU 0, but plain while true; do true; done puts the infinite loop on CPU 3 right along with the make -j4 tasks. This is on Fedora 26, and I don't think I'm doing anything weird. systemd has enabled the cpu controller, but it doesn't seem to have configured anything or created any non-root cgroups. Just a heads up. I haven't tried to diagnose it at all.