From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758346AbYF0L7o (ORCPT ); Fri, 27 Jun 2008 07:59:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755137AbYF0L55 (ORCPT ); Fri, 27 Jun 2008 07:57:57 -0400 Received: from viefep18-int.chello.at ([213.46.255.22]:7165 "EHLO viefep14-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753808AbYF0L5w (ORCPT ); Fri, 27 Jun 2008 07:57:52 -0400 Message-Id: <20080627115211.107047525@chello.nl> References: <20080627114109.724249622@chello.nl> User-Agent: quilt/0.46-1 Date: Fri, 27 Jun 2008 13:41:12 +0200 From: Peter Zijlstra To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Srivatsa Vaddagiri , Mike Galbraith , Peter Zijlstra Subject: [PATCH 03/30] sched: fix calc_delta_asym() Content-Disposition: inline; filename=sched-asyn_gran.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org calc_delta_asym() is supposed to do the same as calc_delta_fair() except linearly shrink the result for negative nice processes - this causes them to have a smaller preemption threshold so that they are more easily preempted. The problem is that for task groups se->load.weight is the per cpu share of the actual task group weight; take that into account. Also provide a debug switch to disable the asymmetry (which I still don't like - but it does greatly benefit some workloads) This would explain the interactivity issues reported against group scheduling. Signed-off-by: Peter Zijlstra --- kernel/sched_fair.c | 28 +++++++++++++++++++++++++++- kernel/sched_features.h | 1 + 2 files changed, 28 insertions(+), 1 deletion(-) Index: linux-2.6/kernel/sched_fair.c =================================================================== --- linux-2.6.orig/kernel/sched_fair.c +++ linux-2.6/kernel/sched_fair.c @@ -430,6 +430,29 @@ calc_delta_asym(unsigned long delta, str for_each_sched_entity(se) { struct load_weight *se_lw = &se->load; +#ifdef CONFIG_FAIR_SCHED_GROUP + struct cfs_rq *cfs_rq = se->my_q; + struct task_group *tg = NULL + + if (cfs_rq) + tg = cfs_rq->tg; + + if (tg && tg->shares < NICE_0_LOAD) { + /* + * scale shares to what it would have been had + * tg->weight been NICE_0_LOAD: + * + * weight = 1024 * shares / tg->weight + */ + lw.weight *= se->load.weight; + lw.weight /= tg->shares; + + lw.inv_weight = 0; + + se_lw = &lw; + } else +#endif + if (se->load.weight < NICE_0_LOAD) se_lw = &lw; @@ -1154,7 +1177,10 @@ static unsigned long wakeup_gran(struct * More easily preempt - nice tasks, while not making it harder for * + nice tasks. */ - gran = calc_delta_asym(sysctl_sched_wakeup_granularity, se); + if (sched_feat(ASYM_GRAN)) + gran = calc_delta_asym(sysctl_sched_wakeup_granularity, se); + else + gran = calc_delta_fair(sysctl_sched_wakeup_granularity, se); return gran; } Index: linux-2.6/kernel/sched_features.h =================================================================== --- linux-2.6.orig/kernel/sched_features.h +++ linux-2.6/kernel/sched_features.h @@ -6,3 +6,4 @@ SCHED_FEAT(CACHE_HOT_BUDDY, 1) SCHED_FEAT(SYNC_WAKEUPS, 1) SCHED_FEAT(HRTICK, 1) SCHED_FEAT(DOUBLE_TICK, 0) +SCHED_FEAT(ASYM_GRAN, 1) --