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From: Patrick Bellasi <patrick.bellasi@arm.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Paul Turner <pjt@google.com>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Juri Lelli <juri.lelli@redhat.com>, Todd Kjos <tkjos@google.com>,
	Joel Fernandes <joelaf@google.com>,
	Steve Muckle <smuckle@google.com>,
	Suren Baghdasaryan <surenb@google.com>
Subject: Re: [PATCH v3 08/14] sched/core: uclamp: extend cpu's cgroup controller
Date: Fri, 17 Aug 2018 15:24:15 +0100
Message-ID: <20180817142415.GK2960@e110439-lin> (raw)
In-Reply-To: <82db1123-339f-0dbf-9332-7e37ee9e4f20@arm.com>

On 17-Aug 14:21, Dietmar Eggemann wrote:
> On 08/06/2018 06:39 PM, Patrick Bellasi wrote:
> 
> [...]
> 
> >Give the above mechanisms, it is now possible to extend the cpu
> >controller to specify what is the minimum (or maximum) utilization which
> >a task is expected (or allowed) to generate.
> >Constraints on minimum and maximum utilization allowed for tasks in a
> >CPU cgroup can improve the control on the actual amount of CPU bandwidth
> >consumed by tasks.
> 
> I assume this is covered by the s/bandwidth/capacity/ you had w/ Juri on
> 01/14.

Yes... I need to update this changelog too.

> [...]
> 
> >diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> >index ff76b000bbe8..2ba55a4afffb 100644
> >--- a/kernel/sched/core.c
> >+++ b/kernel/sched/core.c
> >@@ -1211,6 +1211,74 @@ static inline void uclamp_group_get(struct task_struct *p,
> >  	uclamp_group_put(clamp_id, prev_group_id);
> >  }
> >+#ifdef CONFIG_UCLAMP_TASK_GROUP
> >+/**
> >+ * init_uclamp_sched_group: initialize data structures required for TG's
> >+ *                          utilization clamping
> >+ */
> >+static inline void init_uclamp_sched_group(void)
> >+{
> >+	struct uclamp_map *uc_map;
> >+	struct uclamp_se *uc_se;
> >+	int group_id;
> >+	int clamp_id;
> >+
> >+	/* Root TG's is statically assigned to the first clamp group */
> >+	group_id = 0;
> >+
> >+	/* Initialize root TG's to default (none) clamp values */
> >+	for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id) {
> >+		uc_map = &uclamp_maps[clamp_id][0];
> >+
> >+		/* Map root TG's clamp value */
> >+		uclamp_group_init(clamp_id, group_id, uclamp_none(clamp_id));
> >+
> >+		/* Init root TG's clamp group */
> >+		uc_se = &root_task_group.uclamp[clamp_id];
> >+		uc_se->value = uclamp_none(clamp_id);
> >+		uc_se->group_id = group_id;
> >+
> >+		/* Attach root TG's clamp group */
> >+		uc_map[group_id].se_count = 1;
> >+	}
> >+}
> 
> Can you not save some lines here:
> 
>  static inline void init_uclamp_sched_group(void)
>  {
> -       struct uclamp_map *uc_map;
>         struct uclamp_se *uc_se;
>         int group_id;
>         int clamp_id;
> @@ -1228,8 +1227,6 @@ static inline void init_uclamp_sched_group(void)
> 
>         /* Initialize root TG's to default (none) clamp values */
>         for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id) {
> -               uc_map = &uclamp_maps[clamp_id][0];
> -
>                 /* Map root TG's clamp value */
>                 uclamp_group_init(clamp_id, group_id,
> uclamp_none(clamp_id));
> 
> @@ -1239,7 +1236,7 @@ static inline void init_uclamp_sched_group(void)
>                 uc_se->group_id = group_id;
> 
>                 /* Attach root TG's clamp group */
> -               uc_map[group_id].se_count = 1;
> +               uclamp_maps[clamp_id][group_id].se_count = 1;
>         }
> 
> This would also make uclamp_group_available() smaller.

Unfortunately this var name and its matrix indexes tends to become
quite long easily and in some usages we exceed the 80 columns sometimes.

That's why, for consistency, I always shortcut to *uc_map a reference
to a clamp group and use that variable name consistently in the code.

I'll see if it's possible to get rid of the shortcut in the next version.

-- 
#include <best/regards.h>

Patrick Bellasi

  reply index

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-06 16:39 [PATCH v3 00/14] Add utilization clamping support Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 01/14] sched/core: uclamp: extend sched_setattr to support utilization clamping Patrick Bellasi
2018-08-06 16:50   ` Randy Dunlap
2018-08-09  8:39     ` Patrick Bellasi
2018-08-09 15:20       ` Randy Dunlap
2018-08-07  9:59   ` Juri Lelli
2018-08-13 12:14     ` Patrick Bellasi
2018-08-13 12:27       ` Juri Lelli
2018-08-07 12:35   ` Juri Lelli
2018-08-09  9:14     ` Patrick Bellasi
2018-08-09  9:50       ` Juri Lelli
2018-08-09 15:23         ` Patrick Bellasi
2018-08-10  7:50           ` Juri Lelli
2018-08-17 10:34           ` Quentin Perret
2018-08-17 10:57             ` Patrick Bellasi
2018-08-17 11:14               ` Quentin Perret
2018-08-06 16:39 ` [PATCH v3 02/14] sched/core: uclamp: map TASK's clamp values into CPU's clamp groups Patrick Bellasi
2018-08-14 11:25   ` Pavan Kondeti
2018-08-14 15:21     ` Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 03/14] sched/core: uclamp: add CPU's clamp groups accounting Patrick Bellasi
2018-08-14 15:44   ` Dietmar Eggemann
2018-08-14 16:49     ` Patrick Bellasi
2018-08-15  9:37       ` Dietmar Eggemann
2018-08-15 10:54         ` Patrick Bellasi
2018-08-15 10:59           ` Dietmar Eggemann
2018-08-16 13:32             ` Patrick Bellasi
2018-08-16 13:37               ` Quentin Perret
2018-08-16 13:45                 ` Dietmar Eggemann
2018-08-16 14:21                   ` Quentin Perret
2018-08-16 15:00                     ` Dietmar Eggemann
2018-08-17 11:04   ` Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 04/14] sched/core: uclamp: update CPU's refcount on clamp changes Patrick Bellasi
2018-08-15 15:02   ` Dietmar Eggemann
2018-08-16 13:22     ` Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 05/14] sched/cpufreq: uclamp: add utilization clamping for FAIR tasks Patrick Bellasi
2018-08-08 13:18   ` Vincent Guittot
2018-08-09 15:30     ` Patrick Bellasi
2018-08-15 15:30   ` Dietmar Eggemann
2018-08-16 13:53     ` Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 06/14] sched/cpufreq: uclamp: add utilization clamping for RT tasks Patrick Bellasi
2018-08-07 13:26   ` Juri Lelli
2018-08-09 15:34     ` Patrick Bellasi
2018-08-09 16:03       ` Vincent Guittot
2018-08-13 10:12         ` Patrick Bellasi
2018-08-13 10:50           ` Juri Lelli
2018-08-13 12:07           ` Vincent Guittot
2018-08-13 12:09             ` Vincent Guittot
2018-08-13 12:49             ` Patrick Bellasi
2018-08-13 14:06               ` Vincent Guittot
2018-08-13 15:01                 ` Patrick Bellasi
2018-08-16 10:34                   ` Dietmar Eggemann
2018-08-16 13:40                     ` Patrick Bellasi
2018-08-07 13:54   ` Quentin Perret
2018-08-09 15:41     ` Patrick Bellasi
2018-08-09 15:55       ` Quentin Perret
2018-08-13 10:17         ` Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 07/14] sched/core: uclamp: enforce last task UCLAMP_MAX Patrick Bellasi
2018-08-16 15:43   ` Dietmar Eggemann
2018-08-16 16:47     ` Patrick Bellasi
2018-08-16 17:10       ` Dietmar Eggemann
2018-08-16 17:27         ` Patrick Bellasi
2018-08-16 17:20   ` Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 08/14] sched/core: uclamp: extend cpu's cgroup controller Patrick Bellasi
2018-08-17 12:21   ` Dietmar Eggemann
2018-08-17 14:24     ` Patrick Bellasi [this message]
2018-08-06 16:39 ` [PATCH v3 09/14] sched/core: uclamp: propagate parent clamps Patrick Bellasi
2018-08-16  9:09   ` Pavan Kondeti
2018-08-16 14:07     ` Patrick Bellasi
2018-08-17 13:43   ` Dietmar Eggemann
2018-08-17 14:45     ` Patrick Bellasi
2018-08-17 15:50       ` Dietmar Eggemann
2018-08-20 10:01         ` Dietmar Eggemann
2018-08-20 12:28           ` Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 10/14] sched/core: uclamp: map TG's clamp values into CPU's clamp groups Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 11/14] sched/core: uclamp: use TG's clamps to restrict Task's clamps Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 12/14] sched/core: uclamp: add system default clamps Patrick Bellasi
2018-08-16  9:13   ` Pavan Kondeti
2018-08-16 14:37     ` Patrick Bellasi
2018-08-20 10:18   ` Dietmar Eggemann
2018-08-20 12:27     ` Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 13/14] sched/core: uclamp: update CPU's refcount on TG's clamp changes Patrick Bellasi
2018-08-06 16:39 ` [PATCH v3 14/14] sched/core: uclamp: use percentage clamp values Patrick Bellasi

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