From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: Lukasz Luba <lukasz.luba@arm.com>, Peter Zijlstra <peterz@infradead.org>
Cc: Qais Yousef <qyousef@layalina.io>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
"Rafael J. Wysocki" <rafael@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
juri.lelli@redhat.com
Subject: Re: [RFC PATCH 0/7] sched: cpufreq: Remove magic margins
Date: Fri, 8 Sep 2023 14:51:51 +0200 [thread overview]
Message-ID: <7c1cedb5-6342-1bf9-d1a6-3a87f63801fc@redhat.com> (raw)
In-Reply-To: <8657cc7c-169b-3479-5919-72bd39335b15@arm.com>
On 9/7/23 15:45, Lukasz Luba wrote:
>>>> RT literatur mostly methinks. Replacing WCET with a statistical model of
>>>> sorts is not uncommon, the argument goes that not everybody will have
>>>> their worst case at the same time and lows and highs can commonly cancel
>>>> out and this way we can cram a little more on the system.
>>>>
>>>> Typically this is proposed in the context of soft-realtime systems.
>>>
>>> Thanks Peter, I will dive into some books...
>>
>> I would look at academic papers, not sure any of that ever made it to
>> books, Daniel would know I suppose.
>
> Good hint, thanks!
The key-words that came to my mind are:
- mk-firm, where you accept m tasks will make their deadline
every k execution - like, because you run too long.
- mixed criticality with pWCET (probabilistic execution time) or
average execution time + an sporadic tail execution time for
the low criticality part.
mk-firm smells like 2005's.. mixed criticality as 2015's..present.
You will probably find more papers than books. Read the papers
as a source for inspiration... not necessarily as a definitive
solution. They generally proposed too restrictive task models.
-- Daniel
next prev parent reply other threads:[~2023-09-08 12:52 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-27 23:31 [RFC PATCH 0/7] sched: cpufreq: Remove magic margins Qais Yousef
2023-08-27 23:31 ` [RFC PATCH 1/7] sched/pelt: Add a new function to approximate the future util_avg value Qais Yousef
2023-09-06 12:56 ` Dietmar Eggemann
2023-09-06 21:19 ` Qais Yousef
2023-09-07 11:12 ` Dietmar Eggemann
2023-09-10 19:58 ` Qais Yousef
2023-09-13 17:22 ` Dietmar Eggemann
2023-09-16 19:49 ` Qais Yousef
2023-09-16 19:52 ` Qais Yousef
2023-08-27 23:31 ` [RFC PATCH 2/7] sched/pelt: Add a new function to approximate runtime to reach given util Qais Yousef
2023-09-06 12:56 ` Dietmar Eggemann
2023-09-06 20:44 ` Dietmar Eggemann
2023-09-06 21:38 ` Qais Yousef
2023-09-15 9:15 ` Hongyan Xia
2023-09-16 19:56 ` Qais Yousef
2023-08-27 23:31 ` [RFC PATCH 3/7] sched/fair: Remove magic margin in fits_capacity() Qais Yousef
2023-09-06 14:38 ` Dietmar Eggemann
2023-09-06 21:45 ` Qais Yousef
2023-08-27 23:32 ` [RFC PATCH 4/7] sched: cpufreq: Remove magic 1.25 headroom from apply_dvfs_headroom() Qais Yousef
2023-09-07 11:34 ` Peter Zijlstra
2023-09-10 19:23 ` Qais Yousef
2023-08-27 23:32 ` [RFC PATCH 5/7] sched/schedutil: Add a new tunable to dictate response time Qais Yousef
2023-09-06 21:13 ` Dietmar Eggemann
2023-09-06 21:52 ` Qais Yousef
2023-09-07 11:44 ` Peter Zijlstra
2023-09-10 19:25 ` Qais Yousef
2023-08-27 23:32 ` [RFC PATCH 6/7] sched/pelt: Introduce PELT multiplier Qais Yousef
2023-08-27 23:32 ` [RFC PATCH 7/7] cpufreq: Change default transition delay to 2ms Qais Yousef
2023-09-06 9:18 ` [RFC PATCH 0/7] sched: cpufreq: Remove magic margins Lukasz Luba
2023-09-06 21:18 ` Qais Yousef
2023-09-07 7:48 ` Lukasz Luba
2023-09-07 11:53 ` Peter Zijlstra
2023-09-07 13:06 ` Lukasz Luba
2023-09-07 13:29 ` Peter Zijlstra
2023-09-07 13:33 ` Lukasz Luba
2023-09-07 13:38 ` Peter Zijlstra
2023-09-07 13:45 ` Lukasz Luba
2023-09-08 12:51 ` Daniel Bristot de Oliveira [this message]
2023-09-12 11:57 ` Lukasz Luba
2023-09-10 18:20 ` Qais Yousef
2023-09-10 18:14 ` Qais Yousef
2023-09-07 13:26 ` Peter Zijlstra
2023-09-07 13:57 ` Lukasz Luba
2023-09-07 14:29 ` Peter Zijlstra
2023-09-07 14:42 ` Lukasz Luba
2023-09-07 20:16 ` Peter Zijlstra
2023-09-12 11:51 ` Lukasz Luba
2023-09-12 14:01 ` Vincent Guittot
2023-09-13 9:53 ` Lukasz Luba
2023-09-12 14:28 ` Peter Zijlstra
2023-09-10 19:06 ` Qais Yousef
2023-09-10 18:46 ` Qais Yousef
2023-09-07 13:08 ` Peter Zijlstra
2023-09-08 0:17 ` Qais Yousef
2023-09-08 7:40 ` Dietmar Eggemann
2023-09-08 14:07 ` Qais Yousef
2023-09-12 17:18 ` Dietmar Eggemann
2023-09-16 19:38 ` Qais Yousef
2023-09-08 10:25 ` Peter Zijlstra
2023-09-08 13:33 ` Qais Yousef
2023-09-08 13:58 ` Peter Zijlstra
2023-09-08 13:59 ` Peter Zijlstra
2023-09-08 14:11 ` Qais Yousef
2023-09-10 21:17 ` Qais Yousef
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