From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753273AbdDMN4p (ORCPT ); Thu, 13 Apr 2017 09:56:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3751 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750745AbdDMN4m (ORCPT ); Thu, 13 Apr 2017 09:56:42 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 75CBF8050A Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=lvenanci@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 75CBF8050A From: Lauro Ramos Venancio To: linux-kernel@vger.kernel.org Cc: lwang@redhat.com, riel@redhat.com, Mike Galbraith , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Lauro Ramos Venancio Subject: [RFC 0/3] sched/topology: fix sched groups on NUMA machines with mesh topology Date: Thu, 13 Apr 2017 10:56:06 -0300 Message-Id: <1492091769-19879-1-git-send-email-lvenanci@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 13 Apr 2017 13:56:41 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, the scheduler is not able to directly move tasks between some NUMA nodes 2-hops apart on machines with mesh topology. This occurs because some NUMA nodes belongs to all sched groups. For more details, see the patch 2 commit log. This bug was reported in the paper [1] as "The Scheduling Group Construction bug". This patchset constructs the sched groups from each CPU perspective. So each NUMA node can have different groups in the last NUMA sched domain level. SPECjbb2005 results show up to 63% performance improvement and a huge standard deviation drop on a machine with 8 NUMA nodes and mesh topology. Patch 1 - just prepare the code for patch 2 Patch 2 - change the sched groups construction Patch 3 - fix issue with different groups starting with the same CPU [1] http://www.ece.ubc.ca/~sasha/papers/eurosys16-final29.pdf Regards, Lauro Lauro Ramos Venancio (3): sched/topology: Refactor function build_overlap_sched_groups() sched/topology: fix sched groups on NUMA machines with mesh topology sched/topology: Different sched groups must not have the same balance cpu kernel/sched/topology.c | 165 ++++++++++++++++++++++++++++++++++-------------- 1 file changed, 117 insertions(+), 48 deletions(-) -- 1.8.3.1