From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S940520AbcISNUB (ORCPT ); Mon, 19 Sep 2016 09:20:01 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:48475 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941051AbcISNTT (ORCPT ); Mon, 19 Sep 2016 09:19:19 -0400 To: Dietmar Eggemann , Ingo Molnar , Tejun Heo Cc: linux-kernel@vger.kernel.org, Peter Zijlstra From: Christian Borntraeger Subject: linux-next: new scheduler messages span: 0-15 (max cpu_capacity = 589) when starting KVM guests Date: Mon, 19 Sep 2016 15:19:11 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16091913-0032-0000-0000-00000217C568 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16091913-0033-0000-0000-00001CF3D98E Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-09-19_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609020000 definitions=main-1609190184 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dietmar, Ingo, Tejun, since commit cd92bfd3b8cb0ec2ee825e55a3aee704cd55aea9 sched/core: Store maximum per-CPU capacity in root domain I get tons of messages from the scheduler like [..] span: 0-15 (max cpu_capacity = 589) span: 0-15 (max cpu_capacity = 589) span: 0-15 (max cpu_capacity = 589) span: 0-15 (max cpu_capacity = 589) [..] whenever I start kvm guests with libvirt. The reason seems to be that libvirt via systemd/machined tries to move all guest vcpus into its cpuset and for whatever reasons, the way it is done will always call rebuild_sched_domains from the cgroup code. While the message alone is somewhat of a nuisance, I think rebuilding the scheduling domains for moving kvm vcpus is really expensive. Tejun, do you have an idea whats going on here? Is libvirt using the cgroup interface wrong (e.g. also d a memory migrate or whatever) Christian