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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF005C54FCB for ; Mon, 20 Apr 2020 15:13:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3302206B9 for ; Mon, 20 Apr 2020 15:13:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728155AbgDTPNs (ORCPT ); Mon, 20 Apr 2020 11:13:48 -0400 Received: from foss.arm.com ([217.140.110.172]:50702 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727862AbgDTPNr (ORCPT ); Mon, 20 Apr 2020 11:13:47 -0400 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 B530C31B; Mon, 20 Apr 2020 08:13:46 -0700 (PDT) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.195.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3D4033F73D; Mon, 20 Apr 2020 08:13:44 -0700 (PDT) Date: Mon, 20 Apr 2020 16:13:41 +0100 From: Qais Yousef To: Dietmar Eggemann Cc: Ingo Molnar , Peter Zijlstra , Jonathan Corbet , Juri Lelli , Vincent Guittot , Steven Rostedt , Ben Segall , Mel Gorman , Luis Chamberlain , Kees Cook , Iurii Zaikin , Quentin Perret , Valentin Schneider , Patrick Bellasi , Pavan Kondeti , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 1/2] sched/uclamp: Add a new sysctl to control RT default boost value Message-ID: <20200420151341.7zni3bwroso2kpdc@e107158-lin.cambridge.arm.com> References: <20200403123020.13897-1-qais.yousef@arm.com> <292dbd54-e590-dc4f-41e6-5f86e478c0ee@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <292dbd54-e590-dc4f-41e6-5f86e478c0ee@arm.com> User-Agent: NeoMutt/20171215 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 04/20/20 10:29, Dietmar Eggemann wrote: > On 03.04.20 14:30, Qais Yousef wrote: > > [...] > > > @@ -924,6 +945,14 @@ uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id) > > return uc_req; > > } > > > > +static void uclamp_rt_sync_default_util_min(struct task_struct *p) > > +{ > > + struct uclamp_se *uc_se = &p->uclamp_req[UCLAMP_MIN]; > > + > > + if (!uc_se->user_defined) > > + uclamp_se_set(uc_se, sysctl_sched_rt_default_uclamp_util_min, false); > > +} > > + > > unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id) > > { > > struct uclamp_se uc_eff; > > @@ -1030,6 +1059,12 @@ static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) > > if (unlikely(!p->sched_class->uclamp_enabled)) > > return; > > > > + /* > > + * When sysctl_sched_rt_default_uclamp_util_min value is changed by the > > + * user, we apply any new value on the next wakeup, which is here. > > + */ > > + uclamp_rt_sync_default_util_min(p); > > + > > Does this have to be an extra function? Can we not reuse > uclamp_tg_restrict() by slightly rename it to uclamp_restrict()? Hmm the thing is that we're not restricting here. In contrary we're boosting, so the name would be misleading. > > This function will then deal with enforcing restrictions, whether system > and taskgroup hierarchy related or default value (latter only for rt-min > right now since the others are fixed) related. > > uclamp_eff_get() -> uclamp_restrict() is called from: > > 'enqueue_task(), uclamp_update_active() -> uclamp_rq_inc() -> uclamp_rq_inc_id()' and > > 'task_fits_capacity() -> clamp_task_util(), rt_task_fits_capacity() -> uclamp_eff_value()' and > > 'schedutil_cpu_util(), find_energy_efficient_cpu() -> uclamp_rq_util_with() -> uclamp_eff_value()' > > so there would be more check-points than the one in 'enqueue_task() -> uclamp_rq_inc()' now. I think you're revolving around the same idea that Patrick was suggesting. I think it is possible to do something in uclamp_eff_get() too. Thanks -- Qais Yousef > > Only lightly tested: > > ---8<--- > > From: Dietmar Eggemann > Date: Sun, 19 Apr 2020 01:20:17 +0200 > Subject: [PATCH] sched/core: uclamp: Move uclamp_rt_sync_default_util_min() > into uclamp_tg_restrict() > > Signed-off-by: Dietmar Eggemann > --- > kernel/sched/core.c | 34 +++++++++++++++------------------- > 1 file changed, 15 insertions(+), 19 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 8f4e0d5c7daf..6802113d6d4b 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -899,12 +899,22 @@ unsigned int uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id, > } > > static inline struct uclamp_se > -uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id) > +uclamp_restrict(struct task_struct *p, enum uclamp_id clamp_id) > { > - struct uclamp_se uc_req = p->uclamp_req[clamp_id]; > -#ifdef CONFIG_UCLAMP_TASK_GROUP > - struct uclamp_se uc_max; > + struct uclamp_se uc_req, __maybe_unused uc_max; > + > + if (unlikely(rt_task(p)) && clamp_id == UCLAMP_MIN && > + !uc_req.user_defined) { > + struct uclamp_se *uc_se = &p->uclamp_req[UCLAMP_MIN]; > + int rt_min = sysctl_sched_rt_default_uclamp_util_min; > + > + if (uc_se->value != rt_min) > + uclamp_se_set(uc_se, rt_min, false); > + } > > + uc_req = p->uclamp_req[clamp_id]; > + > +#ifdef CONFIG_UCLAMP_TASK_GROUP > /* > * Tasks in autogroups or root task group will be > * restricted by system defaults. > @@ -933,7 +943,7 @@ uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id) > static inline struct uclamp_se > uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id) > { > - struct uclamp_se uc_req = uclamp_tg_restrict(p, clamp_id); > + struct uclamp_se uc_req = uclamp_restrict(p, clamp_id); > struct uclamp_se uc_max = uclamp_default[clamp_id]; > > /* System default restrictions always apply */ > @@ -943,14 +953,6 @@ uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id) > return uc_req; > } > > -static void uclamp_rt_sync_default_util_min(struct task_struct *p) > -{ > - struct uclamp_se *uc_se = &p->uclamp_req[UCLAMP_MIN]; > - > - if (!uc_se->user_defined) > - uclamp_se_set(uc_se, sysctl_sched_rt_default_uclamp_util_min, false); > -} > - > unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id) > { > struct uclamp_se uc_eff; > @@ -1057,12 +1059,6 @@ static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) > if (unlikely(!p->sched_class->uclamp_enabled)) > return; > > - /* > - * When sysctl_sched_rt_default_uclamp_util_min value is changed by the > - * user, we apply any new value on the next wakeup, which is here. > - */ > - uclamp_rt_sync_default_util_min(p); > - > for_each_clamp_id(clamp_id) > uclamp_rq_inc_id(rq, p, clamp_id); > > -- > 2.17.1