From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947194AbcHRK7V (ORCPT ); Thu, 18 Aug 2016 06:59:21 -0400 Received: from terminus.zytor.com ([198.137.202.10]:58318 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945920AbcHRK7S (ORCPT ); Thu, 18 Aug 2016 06:59:18 -0400 Date: Thu, 18 Aug 2016 03:58:42 -0700 From: tip-bot for Morten Rasmussen Message-ID: Cc: hpa@zytor.com, mingo@kernel.org, vincent.guittot@linaro.org, tglx@linutronix.de, peterz@infradead.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, morten.rasmussen@arm.com, efault@gmx.de Reply-To: linux-kernel@vger.kernel.org, morten.rasmussen@arm.com, torvalds@linux-foundation.org, efault@gmx.de, peterz@infradead.org, tglx@linutronix.de, vincent.guittot@linaro.org, hpa@zytor.com, mingo@kernel.org In-Reply-To: <1469453670-2660-10-git-send-email-morten.rasmussen@arm.com> References: <1469453670-2660-10-git-send-email-morten.rasmussen@arm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/fair: Let asymmetric CPU configurations balance at wake-up Git-Commit-ID: 3273163c6775c4c21823985304c2364b08ca6ea2 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 3273163c6775c4c21823985304c2364b08ca6ea2 Gitweb: http://git.kernel.org/tip/3273163c6775c4c21823985304c2364b08ca6ea2 Author: Morten Rasmussen AuthorDate: Mon, 25 Jul 2016 14:34:26 +0100 Committer: Ingo Molnar CommitDate: Thu, 18 Aug 2016 11:26:56 +0200 sched/fair: Let asymmetric CPU configurations balance at wake-up Currently, SD_WAKE_AFFINE always takes priority over wakeup balancing if SD_BALANCE_WAKE is set on the sched_domains. For asymmetric configurations SD_WAKE_AFFINE is only desirable if the waking task's compute demand (utilization) is suitable for the waking CPU and the previous CPU, and all CPUs within their respective SD_SHARE_PKG_RESOURCES domains (sd_llc). If not, let wakeup balancing take over (find_idlest_{group, cpu}()). This patch makes affine wake-ups conditional on whether both the waker CPU and the previous CPU has sufficient capacity for the waking task, or not, assuming that the CPU capacities within an SD_SHARE_PKG_RESOURCES domain (sd_llc) are homogeneous. Signed-off-by: Morten Rasmussen Signed-off-by: Peter Zijlstra (Intel) Acked-by: Vincent Guittot Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dietmar.eggemann@arm.com Cc: freedom.tan@mediatek.com Cc: keita.kobayashi.ym@renesas.com Cc: mgalbraith@suse.de Cc: sgurrappadi@nvidia.com Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1469453670-2660-10-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index acdc351..61d4854 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -114,6 +114,12 @@ unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; #endif +/* + * The margin used when comparing utilization with CPU capacity: + * util * 1024 < capacity * margin + */ +unsigned int capacity_margin = 1280; /* ~20% */ + static inline void update_load_add(struct load_weight *lw, unsigned long inc) { lw->weight += inc; @@ -5376,6 +5382,32 @@ static int cpu_util(int cpu) return (util >= capacity) ? capacity : util; } +static inline int task_util(struct task_struct *p) +{ + return p->se.avg.util_avg; +} + +/* + * Disable WAKE_AFFINE in the case where task @p doesn't fit in the + * capacity of either the waking CPU @cpu or the previous CPU @prev_cpu. + * + * In that case WAKE_AFFINE doesn't make sense and we'll let + * BALANCE_WAKE sort things out. + */ +static int wake_cap(struct task_struct *p, int cpu, int prev_cpu) +{ + long min_cap, max_cap; + + min_cap = min(capacity_orig_of(prev_cpu), capacity_orig_of(cpu)); + max_cap = cpu_rq(cpu)->rd->max_cpu_capacity; + + /* Minimum capacity is close to max, no need to abort wake_affine */ + if (max_cap - min_cap < max_cap >> 3) + return 0; + + return min_cap * 1024 < task_util(p) * capacity_margin; +} + /* * select_task_rq_fair: Select target runqueue for the waking task in domains * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE, @@ -5399,7 +5431,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f if (sd_flag & SD_BALANCE_WAKE) { record_wakee(p); - want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, tsk_cpus_allowed(p)); + want_affine = !wake_wide(p) && !wake_cap(p, cpu, prev_cpu) + && cpumask_test_cpu(cpu, tsk_cpus_allowed(p)); } rcu_read_lock();