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Date:   Fri, 8 Jul 2022 14:34:23 +0200
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Subject: Re: [PATCH 3/3] sched/deadline: Use sched_dl_entity's dl_density in
 dl_task_fits_capacity()
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To:     Vincent Guittot <vincent.guittot@linaro.org>
Cc:     Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>,
        Mel Gorman <mgorman@suse.de>, Ben Segall <bsegall@google.com>,
        Luca Abeni <luca.abeni@santannapisa.it>,
        linux-kernel@vger.kernel.org
References: <20220629122053.287165-1-dietmar.eggemann@arm.com>
 <20220629122053.287165-4-dietmar.eggemann@arm.com>
 <CAKfTPtAFC5Pk7nfJvSYTmaQNayDoGy40kTnT9j8-yZpDezKNYw@mail.gmail.com>
From:   Dietmar Eggemann <dietmar.eggemann@arm.com>
In-Reply-To: <CAKfTPtAFC5Pk7nfJvSYTmaQNayDoGy40kTnT9j8-yZpDezKNYw@mail.gmail.com>
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On 06/07/2022 12:47, Vincent Guittot wrote:
> On Wed, 29 Jun 2022 at 14:21, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote:

[...]

>>  static inline bool dl_task_fits_capacity(struct task_struct *p, int cpu)
>>  {
>>         unsigned long cap = arch_scale_cpu_capacity(cpu);
>>
>> -       return cap_scale(p->dl.dl_deadline, cap) >= p->dl.dl_runtime;
>> +       return cap >= p->dl.dl_density >> SCHED_CAPACITY_SHIFT;
> 
> There is no direct relation between BW_SHIFT and SCHED_CAPACITY_SHIFT
> and we can change one without modifying the other.
> 
> Should you use (BW_SHIFT-SCHED_CAPACITY_SHIFT) instead of SCHED_CAPACITY_SHIFT ?

Yes, that's better, similar to cpu_bw_dl(). Thanks!

[...]