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From: Valentin Schneider <valentin.schneider@arm.com>
To: Qais Yousef <qais.yousef@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	luca abeni <luca.abeni@santannapisa.it>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Wei Wang <wvw@google.com>, Quentin Perret <qperret@google.com>,
	Alessio Balsini <balsini@google.com>,
	Pavan Kondeti <pkondeti@codeaurora.org>,
	Patrick Bellasi <patrick.bellasi@matbug.net>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] sched/deadline: Improve admission control for asymmetric CPU capacities
Date: Tue, 14 Apr 2020 15:29:00 +0100	[thread overview]
Message-ID: <jhjy2qyrvir.mognet@arm.com> (raw)
In-Reply-To: <20200414114032.wigdlnegism6qqns@e107158-lin.cambridge.arm.com>


On 14/04/20 12:40, Qais Yousef wrote:
>
> I haven't followed this discussion closely, so I could be missing something
> here.
>
> In sched_cpu_dying() we call set_rq_offline() which clears the cpu in
> rq->rd->online.
>
> So the way I read the code
>
>       rd->online = cpumask_and(rd->span, cpu_active_mask)
>
> But I could have easily missed some detail.
>

sched_cpu_dying() is wayyyy below sched_cpu_deactivate(). This doesn't help
at all for the dl_cpu_busy() check in sched_cpu_deactivate().

> Regardless, it seems to me that DL is working around something not right in the
> definition of rd->span or using the wrong variable.
>

What DL is doing now is fine, it only needs to be aligned with the active
mask (which it is). We're making things a bit trickier by adding capacity
values into the mix.

> My 2p :-). I have to go back and read the discussion in more detail.
>
> Thanks

  reply	other threads:[~2020-04-14 14:29 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-08  9:50 [PATCH 0/4] Capacity awareness for SCHED_DEADLINE Dietmar Eggemann
2020-04-08  9:50 ` [PATCH 1/4] sched/topology: Store root domain CPU capacity sum Dietmar Eggemann
2020-04-08 12:29   ` Vincent Guittot
2020-04-08 16:30     ` Dietmar Eggemann
2020-04-08 17:03       ` Vincent Guittot
2020-04-09 13:50         ` Dietmar Eggemann
2020-04-09 14:13           ` Vincent Guittot
2020-04-14  9:20             ` Dietmar Eggemann
2020-04-14 12:45         ` Quentin Perret
2020-04-14 15:27           ` Dietmar Eggemann
2020-04-14 15:43             ` Vincent Guittot
2020-04-08  9:50 ` [PATCH 2/4] sched/deadline: Improve admission control for asymmetric CPU capacities Dietmar Eggemann
2020-04-08 10:42   ` Valentin Schneider
2020-04-08 12:26     ` Dietmar Eggemann
2020-04-08 13:30     ` luca abeni
2020-04-08 14:23       ` Qais Yousef
2020-04-08 15:01       ` Valentin Schneider
2020-04-09 17:29         ` Dietmar Eggemann
2020-04-14 11:40           ` Qais Yousef
2020-04-14 14:29             ` Valentin Schneider [this message]
2020-04-14 15:41               ` Qais Yousef
2020-04-14 14:28           ` Valentin Schneider
2020-04-17 12:19           ` Juri Lelli
2020-04-17 14:55             ` Dietmar Eggemann
2020-04-17 15:08               ` Juri Lelli
2020-04-17 15:47                 ` Juri Lelli
2020-04-08  9:50 ` [PATCH 3/4] sched/deadline: Make DL capacity-aware Dietmar Eggemann
2020-04-10 12:52   ` Juri Lelli
2020-04-15  9:39     ` Dietmar Eggemann
2020-04-15 13:20       ` Juri Lelli
2020-04-15 16:42         ` luca abeni
2020-04-16 13:19           ` Juri Lelli
2020-04-08  9:50 ` [PATCH 4/4] sched/deadline: Implement fallback mechanism for !fit case Dietmar Eggemann
2020-04-09 10:25   ` Qais Yousef
2020-04-09 13:00     ` luca abeni
2020-04-09 14:55       ` Qais Yousef
2020-04-09 18:43         ` Dietmar Eggemann
2020-04-14 11:29           ` Qais Yousef

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