From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752003AbbHMGcQ (ORCPT ); Thu, 13 Aug 2015 02:32:16 -0400 Received: from mga02.intel.com ([134.134.136.20]:8395 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751429AbbHMGcO (ORCPT ); Thu, 13 Aug 2015 02:32:14 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,667,1432623600"; d="scan'208";a="747643552" Date: Thu, 13 Aug 2015 06:41:45 +0800 From: Yuyang Du To: byungchul.park@lge.com Cc: mingo@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched: sync with the cfs_rq when changing sched class Message-ID: <20150812224145.GA2143@intel.com> References: <1439445355-24137-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1439445355-24137-1-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 13, 2015 at 02:55:55PM +0900, byungchul.park@lge.com wrote: > > currently, a task load is synced with its cfs_rq, only when it > leaves from fair class. we also need to sync it with cfs_rq when > it returns back to fair class, too. Syncing it at the time it is switched to fair is not necessary, because since last_update_time if it has ever been updated, the load has become random, IOW, useless. So we simply leave it unattended, and let itself merge in the system. > > #ifdef CONFIG_SMP > /* synchronize task with its prev cfs_rq */ > - if (!queued) > - __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)), > - &se->avg, se->on_rq * scale_load_down(se->load.weight), > - cfs_rq->curr == se, NULL); > - > - /* remove our load when we leave */ > - cfs_rq->avg.load_avg = max_t(long, cfs_rq->avg.load_avg - se->avg.load_avg, 0); > - cfs_rq->avg.load_sum = max_t(s64, cfs_rq->avg.load_sum - se->avg.load_sum, 0); > - cfs_rq->avg.util_avg = max_t(long, cfs_rq->avg.util_avg - se->avg.util_avg, 0); > - cfs_rq->avg.util_sum = max_t(s32, cfs_rq->avg.util_sum - se->avg.util_sum, 0); > + detach_entity_load_avg(cfs_rq, se); > #endif You changed the logic.