From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 450A0C433EF for ; Mon, 11 Apr 2022 08:21:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343705AbiDKIXz (ORCPT ); Mon, 11 Apr 2022 04:23:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236432AbiDKIXx (ORCPT ); Mon, 11 Apr 2022 04:23:53 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 462033E0DD for ; Mon, 11 Apr 2022 01:21:40 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EDDEAED1; Mon, 11 Apr 2022 01:21:39 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 586A33F73B; Mon, 11 Apr 2022 01:21:38 -0700 (PDT) Message-ID: <02350916-aa36-ea53-2c98-91b97f49d27e@arm.com> Date: Mon, 11 Apr 2022 10:21:22 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 From: Dietmar Eggemann Subject: Re: [PATCH] sched: Take thermal pressure into account when determine rt fits capacity To: Xuewen Yan , lukasz.luba@arm.com Cc: rafael@kernel.org, viresh.kumar@linaro.org, mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, rostedt@goodmis.org, linux-kernel@vger.kernel.org, di.shen@unisoc.com, xuewen.yan94@gmail.com References: <20220407051932.4071-1-xuewen.yan@unisoc.com> Content-Language: en-US In-Reply-To: <20220407051932.4071-1-xuewen.yan@unisoc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/04/2022 07:19, Xuewen Yan wrote: > There are cases when the cpu max capacity might be reduced due to thermal. > Take into the thermal pressure into account when judge whether the rt task > fits the cpu. And when schedutil govnor get cpu util, the thermal pressure > also should be considered. > > Signed-off-by: Xuewen Yan > --- > kernel/sched/cpufreq_schedutil.c | 1 + > kernel/sched/rt.c | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index 3dbf351d12d5..285ad51caf0f 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -159,6 +159,7 @@ static void sugov_get_util(struct sugov_cpu *sg_cpu) > struct rq *rq = cpu_rq(sg_cpu->cpu); > unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu); > > + max -= arch_scale_thermal_pressure(sg_cpu->cpu); max' = arch_scale_cpu_capacity() - arch_scale_thermal_pressure() For the energy part (A) we use max' in compute_energy() to cap sum_util and max_util at max' and to call em_cpu_energy(..., max_util, sum_util, max'). This was done to match (B)'s `policy->max` capping. For the frequency part (B) we have freq_qos_update_request() in: power_actor_set_power() ... cdev->ops->set_cur_state() cpufreq_set_cur_state() freq_qos_update_request() <-- ! arch_update_thermal_pressure() restricting `policy->max` which then clamps `target_freq` in: cpufreq_update_util() ... get_next_freq() cpufreq_driver_resolve_freq() __resolve_freq() [...] > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index a32c46889af8..d9982ebd4821 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -466,6 +466,7 @@ static inline bool rt_task_fits_capacity(struct task_struct *p, int cpu) > max_cap = uclamp_eff_value(p, UCLAMP_MAX); > > cpu_cap = capacity_orig_of(cpu); > + cpu_cap -= arch_scale_thermal_pressure(cpu); > > return cpu_cap >= min(min_cap, max_cap); > } IMHO, this should follow what we do with rq->cpu_capacity (capacity_of(), the remaining capacity for CFS). E.g. we use capacity_of() in find_energy_efficient_cpu() and select_idle_capacity() to compare capacities. So we would need a function like scale_rt_capacity() for RT (minus the rq->avg_rt.util_avg) but then also one for DL (minus rq->avg_dl.util_avg and rq->avg_rt.util_avg).