From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp06.au.ibm.com (e23smtp06.au.ibm.com [202.81.31.148]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp06.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id DB4AA2C00D1 for ; Mon, 21 Oct 2013 22:44:58 +1100 (EST) Received: from /spool/local by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 21 Oct 2013 21:44:48 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 4C8012BB0053 for ; Mon, 21 Oct 2013 22:44:38 +1100 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r9LBiQca12189840 for ; Mon, 21 Oct 2013 22:44:26 +1100 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r9LBibuB002878 for ; Mon, 21 Oct 2013 22:44:38 +1100 Subject: [PATCH 0/3] sched: Fixes for task placement in SMT threads To: Peter Zijlstra , Mike Galbraith , Paul Turner , Ingo Molnar From: Vaidyanathan Srinivasan Date: Mon, 21 Oct 2013 17:14:32 +0530 Message-ID: <20131021114002.13291.31478.stgit@drishya> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Cc: Michael Neuling , linux-kernel@vger.kernel.org, Anton Blanchard , Preeti U Murthy , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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(-)