From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754197Ab0HMTpe (ORCPT ); Fri, 13 Aug 2010 15:45:34 -0400 Received: from mga02.intel.com ([134.134.136.20]:13894 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751433Ab0HMTp1 (ORCPT ); Fri, 13 Aug 2010 15:45:27 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.55,365,1278313200"; d="scan'208";a="647482405" Message-Id: <20100813193911.827207098@sbsiddha-MOBL3.sc.intel.com> User-Agent: quilt/0.47-1 Date: Fri, 13 Aug 2010 12:45:40 -0700 From: Suresh Siddha To: a.p.zijlstra@chello.nl, mingo@elte.hu, linux-kernel@vger.kernel.org Cc: chris@frostnet.net, debian00@aliceadsl.fr, hpa@zytor.com, jonathan.protzenko@gmail.com, mans@mansr.com, psastudio@mail.ru, rjw@sisk.pl, stephan.eicher@web.de, sxxe@gmx.de, thomas@archlinux.org, venki@google.com, wonghow@gmail.com, Suresh Siddha , stable@kernel.org Subject: [patch 1/3] sched: init rt_avg stat whenever rq comes online References: <20100813190539.410550989@sbsiddha-MOBL3.sc.intel.com> Content-Disposition: inline; filename=sched_reset_rt_avg_stat_online.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org TSC's get reset after suspend/resume and this leads to a scenario of rq->clock (sched_clock_cpu()) less than rq->age_stamp. This leads to a big value returned by scale_rt_power() and the resulting big group power set by the update_group_power() is causing improper load balancing between busy and idle cpu's after suspend/resume. This resulted in multi-threaded workloads (like kernel-compilation) go slower after suspend/resume cycle on core i5 laptops. Realign rq->age_stamp to rq->clock and reset rq->rt_avg in rq_online_rt(). Addresses the primary issue reported in the https://bugzilla.kernel.org/show_bug.cgi?id=15559 (Bad performance after suspend on Intel i7 and i5) Reported-by: Florian Pritz Signed-off-by: Suresh Siddha Cc: stable@kernel.org [2.6.32+] --- diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index d10c80e..a00af73 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1550,6 +1550,12 @@ static void rq_online_rt(struct rq *rq) __enable_runtime(rq); cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr); + + /* + * Reset RT average stat and its time stamp. + */ + rq->age_stamp = rq->clock; + rq->rt_avg = 0; } /* Assumes rq->lock is held */