From: luca abeni <luca.abeni@santannapisa.it>
To: Quentin Perret <quentin.perret@arm.com>
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 1/6] sched/dl: Improve deadline admission control for asymmetric CPU capacities
Date: Tue, 7 May 2019 16:43:49 +0200 [thread overview]
Message-ID: <20190507164349.2823fdaa@nowhere> (raw)
In-Reply-To: <20190507143125.cjfhdxngcugqmko3@queper01-lin>
On Tue, 7 May 2019 15:31:27 +0100
Quentin Perret <quentin.perret@arm.com> wrote:
> On Tuesday 07 May 2019 at 16:25:23 (+0200), luca abeni wrote:
> > On Tue, 7 May 2019 14:48:52 +0100
> > Quentin Perret <quentin.perret@arm.com> wrote:
> >
> > > Hi Luca,
> > >
> > > On Monday 06 May 2019 at 06:48:31 (+0200), Luca Abeni wrote:
> > > > diff --git a/drivers/base/arch_topology.c
> > > > b/drivers/base/arch_topology.c index edfcf8d982e4..646d6d349d53
> > > > 100644 --- a/drivers/base/arch_topology.c
> > > > +++ b/drivers/base/arch_topology.c
> > > > @@ -36,6 +36,7 @@ DEFINE_PER_CPU(unsigned long, cpu_scale) =
> > > > SCHED_CAPACITY_SCALE;
> > > > void topology_set_cpu_scale(unsigned int cpu, unsigned long
> > > > capacity) {
> > > > + topology_update_cpu_capacity(cpu, per_cpu(cpu_scale,
> > > > cpu), capacity);
> > >
> > > Why is that one needed ? Don't you end up re-building the sched
> > > domains after this anyways ?
> >
> > If I remember correctly, this function was called at boot time when
> > the capacities are assigned to the CPU cores.
> >
> > I do not remember if the sched domain was re-built after this call,
> > but I admit I do not know this part of the kernel very well...
>
> Right and things moved recently in this area, see bb1fbdd3c3fd
> ("sched/topology, drivers/base/arch_topology: Rebuild the sched_domain
> hierarchy when capacities change")
Ah, thanks! I missed this change when rebasing the patchset.
I guess this part of the patch has to be updated (and probably became
useless?), then.
Thanks,
Luca
>
> > This achieved the effect of correctly setting up the "rd_capacity"
> > field, but I do not know if there is a better/simpler way to achieve
> > the same result :)
>
> OK, that's really an implementation detail, so no need to worry too
> much about it at the RFC stage I suppose :-)
>
> Thanks,
> Quentin
next prev parent reply other threads:[~2019-05-07 14:43 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 [this message]
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
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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