From: Quentin Perret <quentin.perret@arm.com>
To: luca abeni <luca.abeni@santannapisa.it>
Cc: linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
"Paul E . McKenney" <paulmck@linux.ibm.com>,
Joel Fernandes <joel@joelfernandes.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Juri Lelli <juri.lelli@redhat.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Patrick Bellasi <patrick.bellasi@arm.com>,
Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>
Subject: Re: [RFC PATCH 2/6] sched/dl: Capacity-aware migrations
Date: Tue, 7 May 2019 16:04:25 +0100 [thread overview]
Message-ID: <20190507150423.xid3j6wcjdbtavdf@queper01-lin> (raw)
In-Reply-To: <20190507161733.1a26419b@nowhere>
On Tuesday 07 May 2019 at 16:17:33 (+0200), luca abeni wrote:
> Hi Quentin,
>
> On Tue, 7 May 2019 14:35:28 +0100
> Quentin Perret <quentin.perret@arm.com> wrote:
>
> > Hi Luca,
> >
> > On Monday 06 May 2019 at 06:48:32 (+0200), Luca Abeni wrote:
> > > +static inline int dl_task_fit(const struct sched_dl_entity *dl_se,
> > > + int cpu, u64 *c)
> > > +{
> > > + u64 cap = (arch_scale_cpu_capacity(NULL, cpu) *
> > > arch_scale_freq_capacity(cpu)) >> SCHED_CAPACITY_SHIFT;
> >
> > I'm a little bit confused by this use of arch_scale_freq_capacity()
> > here. IIUC this means you would say a big DL task doesn't fit on a big
> > CPU just because it happens to be running at a low frequency when this
> > function is called. Is this what we want ?
>
> The idea of this approach was to avoid frequency switches when
> possible; so, I wanted to check if the task fits on a CPU core at its
> current operating frequency.
>
>
> > If the frequency is low, we can (probably) raise it to accommodate
> > this DL task so perhaps we should say it fits ?
>
> In a later patch, if the task does not fit on any core (at its current
> frequency), the task is moved to the core having the maximum capacity
> (without considering the operating frequency --- at least, this was my
> intention when I wrote the patches :)
Ah, I see, patches 05-06. I'll go have a look then !
Thanks,
Quentin
next prev parent reply other threads:[~2019-05-07 15:04 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-06 4:48 [RFC PATCH 0/6] Capacity awareness for SCHED_DEADLINE Luca Abeni
2019-05-06 4:48 ` [RFC PATCH 1/6] sched/dl: Improve deadline admission control for asymmetric CPU capacities Luca Abeni
2019-05-07 13:48 ` Quentin Perret
2019-05-07 13:55 ` Vincent Guittot
2019-05-07 14:02 ` Quentin Perret
2019-05-07 14:25 ` luca abeni
2019-05-07 14:31 ` Quentin Perret
2019-05-07 14:43 ` luca abeni
2019-07-08 11:22 ` Dietmar Eggemann
2019-07-08 15:05 ` Quentin Perret
2019-06-18 16:41 ` Alessio Balsini
2019-05-06 4:48 ` [RFC PATCH 2/6] sched/dl: Capacity-aware migrations Luca Abeni
2019-05-07 13:35 ` Quentin Perret
2019-05-07 14:17 ` luca abeni
2019-05-07 15:04 ` Quentin Perret [this message]
2019-05-07 14:10 ` Quentin Perret
2019-05-07 14:41 ` luca abeni
2019-05-07 15:02 ` Quentin Perret
2019-05-08 8:04 ` Juri Lelli
2019-05-08 8:17 ` luca abeni
2019-07-04 12:05 ` Dietmar Eggemann
2019-07-08 7:41 ` luca abeni
2019-07-08 10:41 ` Dietmar Eggemann
2019-05-06 4:48 ` [RFC PATCH 3/6] sched/dl: Try better placement even for deadline tasks that do not block Luca Abeni
2019-05-07 14:13 ` Quentin Perret
2019-05-07 16:00 ` Morten Rasmussen
2019-05-08 8:01 ` Juri Lelli
2019-05-08 8:14 ` luca abeni
2019-05-08 9:22 ` Juri Lelli
2019-07-08 13:55 ` Peter Zijlstra
2019-07-09 13:24 ` luca abeni
2019-07-09 13:42 ` Peter Zijlstra
2019-07-11 11:17 ` Dietmar Eggemann
2019-07-11 12:00 ` Peter Zijlstra
2019-07-11 15:33 ` Dietmar Eggemann
2019-07-09 14:44 ` Dietmar Eggemann
2019-05-06 4:48 ` [RFC PATCH 4/6] sched/dl: Improve capacity-aware wakeup Luca Abeni
2019-05-08 9:08 ` Juri Lelli
2019-05-08 9:24 ` luca abeni
2019-05-08 12:05 ` Juri Lelli
2019-05-08 12:47 ` luca abeni
2019-05-08 13:10 ` Juri Lelli
2019-05-08 14:12 ` luca abeni
2019-05-06 4:48 ` [RFC PATCH 5/6] sched/dl: If the task does not fit anywhere, select the fastest core Luca Abeni
2019-05-06 4:48 ` [RFC PATCH 6/6] sched/dl: Try not to select a too fast core Luca Abeni
2019-05-07 15:57 ` Quentin Perret
2019-05-08 6:26 ` luca abeni
2019-05-09 13:46 ` Quentin Perret
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