From nobody Sun Feb 8 05:23:27 2026 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 13748C7EE2A for ; Tue, 6 Jun 2023 08:19:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236313AbjFFITI (ORCPT ); Tue, 6 Jun 2023 04:19:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236148AbjFFIS6 (ORCPT ); Tue, 6 Jun 2023 04:18:58 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 56139E40; Tue, 6 Jun 2023 01:18:56 -0700 (PDT) Date: Tue, 06 Jun 2023 08:18:54 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1686039534; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vbZvBwsTqFXWY9oaJ114END5x75WZTbsWPBUYt1EctA=; b=DVIo9BQympy6w2Cvx8DrFNYsCl8qrZj8r269lEo47/+aJaOVXuWDCxAW62iRXzHLwYw8oy UpEV7qJLYngRhVrGqq25OensgLPDcPYxPZCWKCZkoOBZm70xVOv+Hyv2BQd3SkFNs5dO4E aCnJZsUjjRI6BpXN+pa27Mt/95/q0l68zTVjVMqzdVC9/fOvsK6CtA1SZo44CQi2yeEU0L HXz8+7Cw7KYt6z+CZej9tjcd6CPop0OjDt1KajiTK94DqRWniOd/fTKVMg9pK7j/pgE+PR b1B41iSG/8qAzEtzvi3vjJS5F/7TfRi4gAHeBztCOHqeg7jOPI1W9Q73ed07GA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1686039534; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vbZvBwsTqFXWY9oaJ114END5x75WZTbsWPBUYt1EctA=; b=GxVDKjhqyVWoV79iV5SCwyrRckve/zxnlxejQABIxbKA/2xsEcSPnCHHL25E8r9kHoUNYz SgNc1TYQRRJjA+Ag== From: "tip-bot2 for Dietmar Eggemann" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/fair: Refactor CPU utilization functions Cc: Dietmar Eggemann , "Peter Zijlstra (Intel)" , Vincent Guittot , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230515115735.296329-2-dietmar.eggemann@arm.com> References: <20230515115735.296329-2-dietmar.eggemann@arm.com> MIME-Version: 1.0 Message-ID: <168603953443.404.1204658294899368545.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: 3eb6d6ececca2fd566d717b37ab467c246f66be7 Gitweb: https://git.kernel.org/tip/3eb6d6ececca2fd566d717b37ab467c24= 6f66be7 Author: Dietmar Eggemann AuthorDate: Mon, 15 May 2023 13:57:34 +02:00 Committer: Peter Zijlstra CommitterDate: Mon, 05 Jun 2023 21:13:43 +02:00 sched/fair: Refactor CPU utilization functions There is a lot of code duplication in cpu_util_next() & cpu_util_cfs(). Remove this by allowing cpu_util_next() to be called with p =3D NULL. Rename cpu_util_next() to cpu_util() since the '_next' suffix is no longer necessary to distinct cpu utilization related functions. Implement cpu_util_cfs(cpu) as cpu_util(cpu, p =3D NULL, -1). This will allow to code future related cpu util changes only in one place, namely in cpu_util(). Signed-off-by: Dietmar Eggemann Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Vincent Guittot Link: https://lore.kernel.org/r/20230515115735.296329-2-dietmar.eggemann@ar= m.com --- kernel/sched/fair.c | 63 +++++++++++++++++++++++++++++++++---------- kernel/sched/sched.h | 47 +-------------------------------- 2 files changed, 50 insertions(+), 60 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index df0ff90..09e3be2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7202,11 +7202,41 @@ static int select_idle_sibling(struct task_struct *= p, int prev, int target) return target; } =20 -/* - * Predicts what cpu_util(@cpu) would return if @p was removed from @cpu - * (@dst_cpu =3D -1) or migrated to @dst_cpu. - */ -static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst= _cpu) +/** + * cpu_util() - Estimates the amount of CPU capacity used by CFS tasks. + * @cpu: the CPU to get the utilization for + * @p: task for which the CPU utilization should be predicted or NULL + * @dst_cpu: CPU @p migrates to, -1 if @p moves from @cpu or @p =3D=3D NULL + * + * The unit of the return value must be the same as the one of CPU capacity + * so that CPU utilization can be compared with CPU capacity. + * + * CPU utilization is the sum of running time of runnable tasks plus the + * recent utilization of currently non-runnable tasks on that CPU. + * It represents the amount of CPU capacity currently used by CFS tasks in + * the range [0..max CPU capacity] with max CPU capacity being the CPU + * capacity at f_max. + * + * The estimated CPU utilization is defined as the maximum between CPU + * utilization and sum of the estimated utilization of the currently + * runnable tasks on that CPU. It preserves a utilization "snapshot" of + * previously-executed tasks, which helps better deduce how busy a CPU will + * be when a long-sleeping task wakes up. The contribution to CPU utilizat= ion + * of such a task would be significantly decayed at this point of time. + * + * CPU utilization can be higher than the current CPU capacity + * (f_curr/f_max * max CPU capacity) or even the max CPU capacity because + * of rounding errors as well as task migrations or wakeups of new tasks. + * CPU utilization has to be capped to fit into the [0..max CPU capacity] + * range. Otherwise a group of CPUs (CPU0 util =3D 121% + CPU1 util =3D 80= %) + * could be seen as over-utilized even though CPU1 has 20% of spare CPU + * capacity. CPU utilization is allowed to overshoot current CPU capacity + * though since this is useful for predicting the CPU capacity required + * after task migrations (scheduler-driven DVFS). + * + * Return: (Estimated) utilization for the specified CPU. + */ +static unsigned long cpu_util(int cpu, struct task_struct *p, int dst_cpu) { struct cfs_rq *cfs_rq =3D &cpu_rq(cpu)->cfs; unsigned long util =3D READ_ONCE(cfs_rq->avg.util_avg); @@ -7217,9 +7247,9 @@ static unsigned long cpu_util_next(int cpu, struct ta= sk_struct *p, int dst_cpu) * contribution. In all the other cases @cpu is not impacted by the * migration so its util_avg is already correct. */ - if (task_cpu(p) =3D=3D cpu && dst_cpu !=3D cpu) + if (p && task_cpu(p) =3D=3D cpu && dst_cpu !=3D cpu) lsub_positive(&util, task_util(p)); - else if (task_cpu(p) !=3D cpu && dst_cpu =3D=3D cpu) + else if (p && task_cpu(p) !=3D cpu && dst_cpu =3D=3D cpu) util +=3D task_util(p); =20 if (sched_feat(UTIL_EST)) { @@ -7255,7 +7285,7 @@ static unsigned long cpu_util_next(int cpu, struct ta= sk_struct *p, int dst_cpu) */ if (dst_cpu =3D=3D cpu) util_est +=3D _task_util_est(p); - else if (unlikely(task_on_rq_queued(p) || current =3D=3D p)) + else if (p && unlikely(task_on_rq_queued(p) || current =3D=3D p)) lsub_positive(&util_est, _task_util_est(p)); =20 util =3D max(util, util_est); @@ -7264,6 +7294,11 @@ static unsigned long cpu_util_next(int cpu, struct t= ask_struct *p, int dst_cpu) return min(util, capacity_orig_of(cpu)); } =20 +unsigned long cpu_util_cfs(int cpu) +{ + return cpu_util(cpu, NULL, -1); +} + /* * cpu_util_without: compute cpu utilization without any contributions fro= m *p * @cpu: the CPU which utilization is requested @@ -7281,9 +7316,9 @@ static unsigned long cpu_util_without(int cpu, struct= task_struct *p) { /* Task has no contribution or is new */ if (cpu !=3D task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time)) - return cpu_util_cfs(cpu); + p =3D NULL; =20 - return cpu_util_next(cpu, p, -1); + return cpu_util(cpu, p, -1); } =20 /* @@ -7330,7 +7365,7 @@ static inline void eenv_task_busy_time(struct energy_= env *eenv, * cpu_capacity. * * The contribution of the task @p for which we want to estimate the - * energy cost is removed (by cpu_util_next()) and must be calculated + * energy cost is removed (by cpu_util()) and must be calculated * separately (see eenv_task_busy_time). This ensures: * * - A stable PD utilization, no matter which CPU of that PD we want to = place @@ -7351,7 +7386,7 @@ static inline void eenv_pd_busy_time(struct energy_en= v *eenv, int cpu; =20 for_each_cpu(cpu, pd_cpus) { - unsigned long util =3D cpu_util_next(cpu, p, -1); + unsigned long util =3D cpu_util(cpu, p, -1); =20 busy_time +=3D effective_cpu_util(cpu, util, ENERGY_UTIL, NULL); } @@ -7375,7 +7410,7 @@ eenv_pd_max_util(struct energy_env *eenv, struct cpum= ask *pd_cpus, =20 for_each_cpu(cpu, pd_cpus) { struct task_struct *tsk =3D (cpu =3D=3D dst_cpu) ? p : NULL; - unsigned long util =3D cpu_util_next(cpu, p, dst_cpu); + unsigned long util =3D cpu_util(cpu, p, dst_cpu); unsigned long cpu_util; =20 /* @@ -7521,7 +7556,7 @@ static int find_energy_efficient_cpu(struct task_stru= ct *p, int prev_cpu) if (!cpumask_test_cpu(cpu, p->cpus_ptr)) continue; =20 - util =3D cpu_util_next(cpu, p, cpu); + util =3D cpu_util(cpu, p, cpu); cpu_cap =3D capacity_of(cpu); =20 /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d8ba81c..aaf6fc2 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2955,53 +2955,8 @@ static inline unsigned long cpu_util_dl(struct rq *r= q) return READ_ONCE(rq->avg_dl.util_avg); } =20 -/** - * cpu_util_cfs() - Estimates the amount of CPU capacity used by CFS tasks. - * @cpu: the CPU to get the utilization for. - * - * The unit of the return value must be the same as the one of CPU capacity - * so that CPU utilization can be compared with CPU capacity. - * - * CPU utilization is the sum of running time of runnable tasks plus the - * recent utilization of currently non-runnable tasks on that CPU. - * It represents the amount of CPU capacity currently used by CFS tasks in - * the range [0..max CPU capacity] with max CPU capacity being the CPU - * capacity at f_max. - * - * The estimated CPU utilization is defined as the maximum between CPU - * utilization and sum of the estimated utilization of the currently - * runnable tasks on that CPU. It preserves a utilization "snapshot" of - * previously-executed tasks, which helps better deduce how busy a CPU will - * be when a long-sleeping task wakes up. The contribution to CPU utilizat= ion - * of such a task would be significantly decayed at this point of time. - * - * CPU utilization can be higher than the current CPU capacity - * (f_curr/f_max * max CPU capacity) or even the max CPU capacity because - * of rounding errors as well as task migrations or wakeups of new tasks. - * CPU utilization has to be capped to fit into the [0..max CPU capacity] - * range. Otherwise a group of CPUs (CPU0 util =3D 121% + CPU1 util =3D 80= %) - * could be seen as over-utilized even though CPU1 has 20% of spare CPU - * capacity. CPU utilization is allowed to overshoot current CPU capacity - * though since this is useful for predicting the CPU capacity required - * after task migrations (scheduler-driven DVFS). - * - * Return: (Estimated) utilization for the specified CPU. - */ -static inline unsigned long cpu_util_cfs(int cpu) -{ - struct cfs_rq *cfs_rq; - unsigned long util; - - cfs_rq =3D &cpu_rq(cpu)->cfs; - util =3D READ_ONCE(cfs_rq->avg.util_avg); =20 - if (sched_feat(UTIL_EST)) { - util =3D max_t(unsigned long, util, - READ_ONCE(cfs_rq->avg.util_est.enqueued)); - } - - return min(util, capacity_orig_of(cpu)); -} +extern unsigned long cpu_util_cfs(int cpu); =20 static inline unsigned long cpu_util_rt(struct rq *rq) {