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From: Peter Zijlstra <peterz@infradead.org>
To: Youssef Esmat <youssefesmat@chromium.org>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>,
	mingo@kernel.org, vincent.guittot@linaro.org,
	linux-kernel@vger.kernel.org, juri.lelli@redhat.com,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
	corbet@lwn.net, qyousef@layalina.io, chris.hyser@oracle.com,
	patrick.bellasi@matbug.net, pjt@google.com, pavel@ucw.cz,
	qperret@google.com, tim.c.chen@linux.intel.com,
	joshdon@google.com, timj@gnu.org, kprateek.nayak@amd.com,
	yu.c.chen@intel.com, joel@joelfernandes.org, efault@gmx.de,
	tglx@linutronix.de
Subject: Re: [PATCH 00/15] sched: EEVDF and latency-nice and/or slice-attr
Date: Mon, 2 Oct 2023 20:41:36 +0200	[thread overview]
Message-ID: <20231002184136.GA1539@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CA+q576MS0-MV1Oy-eecvmYpvNT3tqxD8syzrpxQ-Zk310hvRbw@mail.gmail.com>

On Fri, Sep 29, 2023 at 11:54:25AM -0500, Youssef Esmat wrote:
> >
> > EEVDF fundamentally supports per task request/slice sizes, which is the
> > primary motivator for finally finishing these patches.
> >
> > So the plan is to extend sched_setattr() to allow tasks setting their
> > own ideal slice length. But we're not quite there yet.
> >
> > Having just returned from PTO the mailbox is an utter trainwreck, but
> > I'll try and refresh those few patches this week for consideration.
> >
> > In the meantime I think you found the right knob to twiddle.
> 
> Hello Peter,
> 
> I am trying to understand a little better the need for the eligibility
> checks (entity_eligible). I understand the general concept, but I am
> trying to find a scenario where it is necessary. And maybe propose to
> have it toggled by a feature flag.

My initial response was that it ensures fairness, but thinking a little
about it I'm not so sure anymore.

I do think it features in section 6 lemma 4 and 5, which provide
interference bounds. But I'd have to think a little more about it.

The current setup, where all requests are of equal size, then virtual
deadline tree is basically identical to the virtual runtime tree, just
transposed (in the static state scenario).

When mixing request sizes things become a little more interesting.

Let me ponder this a little bit more.

  parent reply	other threads:[~2023-10-02 18:42 UTC|newest]

Thread overview: 104+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-31 11:58 [PATCH 00/15] sched: EEVDF and latency-nice and/or slice-attr Peter Zijlstra
2023-05-31 11:58 ` [PATCH 01/15] sched/fair: Add avg_vruntime Peter Zijlstra
2023-06-02 13:51   ` Vincent Guittot
2023-06-02 14:27     ` Peter Zijlstra
2023-06-05  7:18       ` Vincent Guittot
2023-08-10  7:10   ` [tip: sched/core] sched/fair: Add cfs_rq::avg_vruntime tip-bot2 for Peter Zijlstra
2023-10-11  4:15   ` [PATCH 01/15] sched/fair: Add avg_vruntime Abel Wu
2023-10-11  7:30     ` Peter Zijlstra
2023-10-11  8:30       ` Abel Wu
2023-10-11  9:45         ` Peter Zijlstra
2023-10-11 10:05           ` Peter Zijlstra
2023-10-11 13:08       ` Peter Zijlstra
2023-05-31 11:58 ` [PATCH 02/15] sched/fair: Remove START_DEBIT Peter Zijlstra
2023-08-10  7:10   ` [tip: sched/core] sched/fair: Remove sched_feat(START_DEBIT) tip-bot2 for Peter Zijlstra
2023-05-31 11:58 ` [PATCH 03/15] sched/fair: Add lag based placement Peter Zijlstra
2023-08-10  7:10   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2023-10-11 12:00   ` [PATCH 03/15] " Abel Wu
2023-10-11 13:24     ` Peter Zijlstra
2023-10-12  7:04       ` Abel Wu
2023-10-13  7:37         ` Peter Zijlstra
2023-10-13  8:14           ` Abel Wu
2023-10-12 19:15   ` Benjamin Segall
2023-10-12 22:34     ` Peter Zijlstra
2023-10-13 16:35       ` Peter Zijlstra
2023-10-14  8:08         ` Mike Galbraith
2023-10-13 14:34     ` Peter Zijlstra
2023-05-31 11:58 ` [PATCH 04/15] rbtree: Add rb_add_augmented_cached() helper Peter Zijlstra
2023-08-10  7:10   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2023-05-31 11:58 ` [PATCH 05/15] sched/fair: Implement an EEVDF like policy Peter Zijlstra
2023-08-10  7:10   ` [tip: sched/core] sched/fair: Implement an EEVDF-like scheduling policy tip-bot2 for Peter Zijlstra
2023-09-29 21:40   ` [PATCH 05/15] sched/fair: Implement an EEVDF like policy Benjamin Segall
2023-10-02 17:39     ` Peter Zijlstra
2023-10-11  4:14     ` Abel Wu
2023-10-11  7:33       ` Peter Zijlstra
2023-10-11 11:49         ` Abel Wu
2023-09-30  0:09   ` [PATCH] sched/fair: fix pick_eevdf to always find the correct se Benjamin Segall
2023-10-03 10:42     ` [tip: sched/urgent] sched/fair: Fix pick_eevdf() tip-bot2 for Benjamin Segall
     [not found]     ` <CGME20231004203940eucas1p2f73b017497d1f4239a6e236fdb6019e2@eucas1p2.samsung.com>
2023-10-04 20:39       ` [PATCH] sched/fair: fix pick_eevdf to always find the correct se Marek Szyprowski
2023-10-09  7:53     ` [tip: sched/urgent] sched/eevdf: Fix pick_eevdf() tip-bot2 for Benjamin Segall
2023-10-11 12:12     ` [PATCH] sched/fair: fix pick_eevdf to always find the correct se Abel Wu
2023-10-11 13:14       ` Peter Zijlstra
2023-10-12 10:04         ` Abel Wu
2023-10-11 21:01       ` Benjamin Segall
2023-10-12 10:25         ` Abel Wu
2023-10-12 17:51           ` Benjamin Segall
2023-10-13  3:46             ` Abel Wu
2023-10-13 16:51               ` Benjamin Segall
2023-05-31 11:58 ` [PATCH 06/15] sched: Commit to lag based placement Peter Zijlstra
2023-08-10  7:10   ` [tip: sched/core] sched/fair: " tip-bot2 for Peter Zijlstra
2023-05-31 11:58 ` [PATCH 07/15] sched/smp: Use lag to simplify cross-runqueue placement Peter Zijlstra
2023-08-10  7:10   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2023-09-12 15:32   ` [PATCH 07/15] " Sebastian Andrzej Siewior
2023-09-13  9:03     ` Peter Zijlstra
2023-10-04  1:17   ` [PATCH] sched/fair: Preserve PLACE_DEADLINE_INITIAL deadline Daniel Jordan
2023-10-04 13:09     ` [PATCH v2] " Daniel Jordan
2023-10-04 15:46       ` Chen Yu
2023-10-06 16:31         ` Daniel Jordan
2023-10-12  4:48       ` K Prateek Nayak
2023-10-05  5:56     ` [PATCH] " K Prateek Nayak
2023-10-06 16:35       ` Daniel Jordan
2023-10-06 16:48   ` [PATCH] sched/fair: Always update_curr() before placing at enqueue Daniel Jordan
2023-10-06 19:58     ` Peter Zijlstra
2023-10-18  0:43       ` Daniel Jordan
2023-10-16  5:39     ` K Prateek Nayak
2023-05-31 11:58 ` [PATCH 08/15] sched: Commit to EEVDF Peter Zijlstra
2023-06-16 21:23   ` Joel Fernandes
2023-06-22 12:01     ` Ingo Molnar
2023-06-22 13:11       ` Joel Fernandes
2023-08-10  7:10   ` [tip: sched/core] sched/fair: " tip-bot2 for Peter Zijlstra
2023-05-31 11:58 ` [PATCH 09/15] sched/debug: Rename min_granularity to base_slice Peter Zijlstra
2023-08-10  7:10   ` [tip: sched/core] sched/debug: Rename sysctl_sched_min_granularity to sysctl_sched_base_slice tip-bot2 for Peter Zijlstra
2023-05-31 11:58 ` [PATCH 10/15] sched/fair: Propagate enqueue flags into place_entity() Peter Zijlstra
2023-08-10  7:10   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2023-05-31 11:58 ` [PATCH 11/15] sched/eevdf: Better handle mixed slice length Peter Zijlstra
2023-06-02 13:45   ` Vincent Guittot
2023-06-02 15:06     ` Peter Zijlstra
2023-06-10  6:34   ` Chen Yu
2023-06-10 11:22     ` Peter Zijlstra
2023-05-31 11:58 ` [RFC][PATCH 12/15] sched: Introduce latency-nice as a per-task attribute Peter Zijlstra
2023-05-31 11:58 ` [RFC][PATCH 13/15] sched/fair: Implement latency-nice Peter Zijlstra
2023-06-06 14:54   ` Vincent Guittot
2023-06-08 10:34     ` Peter Zijlstra
2023-06-08 12:44       ` Peter Zijlstra
2023-10-11 23:24   ` Benjamin Segall
2023-05-31 11:58 ` [RFC][PATCH 14/15] sched/fair: Add sched group latency support Peter Zijlstra
2023-05-31 11:58 ` [RFC][PATCH 15/15] sched/eevdf: Use sched_attr::sched_runtime to set request/slice Peter Zijlstra
2023-06-01 13:55   ` Vincent Guittot
2023-06-08 11:52     ` Peter Zijlstra
2023-08-24  0:52 ` [PATCH 00/15] sched: EEVDF and latency-nice and/or slice-attr Daniel Jordan
2023-09-06 13:13   ` Peter Zijlstra
2023-09-29 16:54     ` Youssef Esmat
2023-10-02 15:55       ` Youssef Esmat
2023-10-02 18:41       ` Peter Zijlstra [this message]
2023-10-05 12:05         ` Peter Zijlstra
2023-10-05 14:14           ` Peter Zijlstra
2023-10-05 14:42             ` Peter Zijlstra
2023-10-05 18:23           ` Youssef Esmat
2023-10-06  0:36             ` Youssef Esmat
2023-10-10  8:08             ` Peter Zijlstra
2023-10-07 22:04           ` Peter Zijlstra
2023-10-09 14:41             ` Peter Zijlstra
2023-10-10  0:51             ` Youssef Esmat
2023-10-10  8:01               ` Peter Zijlstra
2023-10-16 16:50               ` Peter Zijlstra

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