Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753391Ab3JULow (ORCPT ); Mon, 21 Oct 2013 07:44:52 -0400 Received: from e23smtp08.au.ibm.com ([202.81.31.141]:42945 "EHLO e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753205Ab3JULov (ORCPT ); Mon, 21 Oct 2013 07:44:51 -0400 Subject: [PATCH 0/3] sched: Fixes for task placement in SMT threads To: Peter Zijlstra , Mike Galbraith , Paul Turner , Ingo Molnar From: Vaidyanathan Srinivasan Cc: Michael Neuling , Benjamin Herrenschmidt , linux-kernel@vger.kernel.org, Anton Blanchard , Preeti U Murthy , linuxppc-dev@lists.ozlabs.org Date: Mon, 21 Oct 2013 17:14:32 +0530 Message-ID: <20131021114002.13291.31478.stgit@drishya> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13102111-5140-0000-0000-00000406D858 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1916 Lines: 50 Hi, The following series fixes scheduler loadbalancing issues where we are missing opportunity to place tasks in SMT threads optimally especially on a POWER7 system. PATCH 1/3, Fixes the scenario where load balancing fails to move tasks away from the cpus in a domain which has SHARE_PKG_RESOURCES set even under the presence of idle cpus in other domains. PATCH 2/3, ensures lower order SMT threads are used for the SD_ASYM_PACKING load balancing case. PATCH 3/3, tries to fix the problem that is explained in its changelog. The following experiment expose the scenario: A task placement test was conducted on a POWER7 as well as multi-core x86 system. At the beginning, tasks are pinned to all the threads within a core and later only the tasks pinned to the secondary threads in a core are unpinned. This leaves the primary thread with tasks that are unmovable, while the rest are free to be moved. Under the above setup, load balancing today does not move the unpinned tasks away from the secondary threads of the core in the above experiment although there are other idle cpus. The PATCH 3/3 fixes this situation and improves task placement even if some of the tasks in a core are pinned. This series applies on v3.12-rc6 and tested on x86 and powerpc. --Vaidy --- Preeti U Murthy (2): sched: Fix nohz_kick_needed to consider the nr_busy of the parent domain's group sched: Aggressive balance in domains whose groups share package resources Vaidyanathan Srinivasan (1): sched: Fix asymmetric scheduling for POWER7 kernel/sched/fair.c | 41 +++++++++++++++++++++++++++++++++-------- 1 file changed, 33 insertions(+), 8 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/