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Message-ID: <01191fe9-72f5-e9a3-ea11-2f0ce8a2933b@redhat.com>
Date:   Fri, 16 Jun 2023 15:18:22 +0200
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Subject: Re: [RFC PATCH V3 5/6] sched/fair: Add trivial fair server
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To:     Peter Zijlstra <peterz@infradead.org>,
        Daniel Bristot de Oliveira <bristot@kernel.org>
Cc:     Ingo Molnar <mingo@redhat.com>, Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Valentin Schneider <vschneid@redhat.com>,
        linux-kernel@vger.kernel.org,
        Luca Abeni <luca.abeni@santannapisa.it>,
        Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>,
        Thomas Gleixner <tglx@linutronix.de>,
        Joel Fernandes <joel@joelfernandes.org>,
        Vineeth Pillai <vineeth@bitbyteword.org>,
        Shuah Khan <skhan@linuxfoundation.org>
References: <cover.1686239016.git.bristot@kernel.org>
 <8db5a49ea92ad8b875d331d6136721645a382fe8.1686239016.git.bristot@kernel.org>
 <20230616125946.GN83892@hirez.programming.kicks-ass.net>
 <c8a48cd8-b3bf-743c-55c5-f942fbe08792@kernel.org>
 <20230616131243.GO83892@hirez.programming.kicks-ass.net>
From:   Daniel Bristot de Oliveira <bristot@redhat.com>
In-Reply-To: <20230616131243.GO83892@hirez.programming.kicks-ass.net>
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On 6/16/23 15:12, Peter Zijlstra wrote:
> On Fri, Jun 16, 2023 at 03:00:57PM +0200, Daniel Bristot de Oliveira wrote:
>> On 6/16/23 14:59, Peter Zijlstra wrote:
>>> On Thu, Jun 08, 2023 at 05:58:17PM +0200, Daniel Bristot de Oliveira wrote:
>>>> +void fair_server_init(struct rq *rq)
>>>> +{
>>>> +	struct sched_dl_entity *dl_se = &rq->fair_server;
>>>> +
>>>> +	init_dl_entity(dl_se);
>>>> +
>>>> +	dl_se->dl_runtime = TICK_NSEC;
>>>> +	dl_se->dl_deadline = 20 * TICK_NSEC;
>>>> +	dl_se->dl_period = 20 * TICK_NSEC;
>>>> +
>>>> +	dl_server_init(dl_se, rq, fair_server_has_tasks, fair_server_pick);
>>>> +}
>>>
>>> These here numbers should obviously become a tunable somewhere... :-)
>>
>> From sched_rt_runtime and sched_rt_period, no?
> 
> Well, probably new names. IIRC those are also limits on the whole
> rt-cgroup mess, so e can't trivially change it without also ripping all
> that out, and that's a little bit more work.
> 
> Ripping out the basic throttle is much simpler than replacing all that
> and should be done earlier.
> 

Life is easier then. Should them be a sysctl?

Like:
  kernel.sched_other_min_runtime_us ?
  kernel.sched_other_min_period_us ?

I bet you can come up with better names.

-- Daniel