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From: Hongyan Xia <hongyan.xia2@arm.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Luis Machado <luis.machado@arm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 08/10] sched/fair: Implement delayed dequeue
Date: Mon, 3 Jun 2024 16:57:15 +0100	[thread overview]
Message-ID: <788a0c8a-79b9-4a06-9739-8b62498bde90@arm.com> (raw)
In-Reply-To: <20240523093338.GJ40213@noisy.programming.kicks-ass.net>

On 23/05/2024 10:33, Peter Zijlstra wrote:
> On Thu, May 23, 2024 at 10:06:04AM +0100, Luis Machado wrote:
> 
>> Booting the kernel with NO_DELAY_DEQUEUE (default to false), things work fine. Then
>> if I switch to DELAY_DEQUEUE at runtime, things start using a lot more power.
>>
>> The interesting bit is if I switch to NO_DELAY_DEQUEUE again at runtime, things don't
>> go back to normal. Rather they stay the same, using a lot more energy.
> 
> Ooh, cute.. weird. I'll try and see if we leak state somehow.

Hi. I'm working on uclamp anyway so I just gave this series (and all 
fixes mentioned in this thread) a go.

It seems after running with this series for a while, suddenly uclamp_max 
no longer works. Running a task with uclamp_max of 110 still sees an rq 
uclamp_max of 1024. Also weirdly, the PELT signal of that uclamp_max is 
completely broken. It goes up to a very high value and then suddenly 
drops to almost 0 from time to time.

I wonder if the reason Luis saw that is because he was the first one to 
run delayed dequeue with uclamp. I'm not familiar enough with the series 
to know how it could possibly affect uclamp so investigating in this 
front may be worth trying. Maybe some leaked uclamp state on the rq?

  reply	other threads:[~2024-06-03 15:57 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-05 10:27 [RFC][PATCH 00/10] sched/fair: Complete EEVDF Peter Zijlstra
2024-04-05 10:27 ` [RFC][PATCH 01/10] sched/eevdf: Add feature comments Peter Zijlstra
2024-04-05 10:27 ` [RFC][PATCH 02/10] sched/eevdf: Remove min_vruntime_copy Peter Zijlstra
2024-04-05 10:27 ` [RFC][PATCH 03/10] sched/fair: Cleanup pick_task_fair() vs throttle Peter Zijlstra
2024-04-05 21:11   ` Benjamin Segall
2024-04-05 10:27 ` [RFC][PATCH 04/10] sched/fair: Cleanup pick_task_fair()s curr Peter Zijlstra
2024-04-05 10:27 ` [RFC][PATCH 05/10] sched/fair: Unify pick_{,next_}_task_fair() Peter Zijlstra
2024-04-06  2:20   ` Mike Galbraith
2024-04-05 10:28 ` [RFC][PATCH 06/10] sched: Allow sched_class::dequeue_task() to fail Peter Zijlstra
2024-04-05 10:28 ` [RFC][PATCH 07/10] sched/fair: Re-organize dequeue_task_fair() Peter Zijlstra
2024-04-05 10:28 ` [RFC][PATCH 08/10] sched/fair: Implement delayed dequeue Peter Zijlstra
2024-04-06  9:23   ` Chen Yu
2024-04-08  9:06     ` Peter Zijlstra
2024-04-11  1:32       ` Yan-Jie Wang
2024-04-25 10:25         ` Peter Zijlstra
2024-04-12 10:42   ` K Prateek Nayak
2024-04-15 10:56     ` Mike Galbraith
2024-04-16  3:18       ` K Prateek Nayak
2024-04-16  5:36         ` Mike Galbraith
2024-04-18 16:24           ` Mike Galbraith
2024-04-18 17:08             ` K Prateek Nayak
2024-04-24 15:20             ` Peter Zijlstra
2024-04-25 11:28             ` Peter Zijlstra
2024-04-26 10:56               ` Peter Zijlstra
2024-04-26 11:16                 ` Peter Zijlstra
2024-04-26 16:03                   ` Mike Galbraith
2024-04-27  6:42                     ` Mike Galbraith
2024-04-28 16:32                       ` Mike Galbraith
2024-04-29 12:14                         ` Peter Zijlstra
2024-04-15 17:07   ` Luis Machado
2024-04-24 15:15     ` Luis Machado
2024-04-25 10:42       ` Peter Zijlstra
2024-04-25 11:49         ` Peter Zijlstra
2024-04-26  9:32           ` Peter Zijlstra
2024-04-26  9:36             ` Peter Zijlstra
2024-04-26 10:16             ` Luis Machado
2024-04-29 14:33             ` Luis Machado
2024-05-02 10:26               ` Luis Machado
2024-05-10 14:49                 ` Luis Machado
2024-05-15  9:36                   ` Peter Zijlstra
2024-05-15 11:48                     ` Peter Zijlstra
2024-05-15 18:03                       ` Mike Galbraith
2024-05-20 15:20                       ` Luis Machado
2024-05-29 22:50                 ` Peter Zijlstra
2024-06-03 19:30                   ` Luis Machado
2024-06-04 10:11                     ` Peter Zijlstra
2024-06-04 13:59                       ` Hongyan Xia
2024-06-04 14:23                       ` Luis Machado
2024-06-04 14:49                         ` Hongyan Xia
2024-06-04 19:12                         ` Peter Zijlstra
2024-06-05  7:22                           ` Peter Zijlstra
2024-06-05  9:14                             ` Luis Machado
2024-06-05  9:42                               ` Peter Zijlstra
2024-06-12 15:08                                 ` Luis Machado
2024-05-23  8:45               ` Peter Zijlstra
2024-05-23  9:06                 ` Luis Machado
2024-05-23  9:33                   ` Peter Zijlstra
2024-06-03 15:57                     ` Hongyan Xia [this message]
2024-04-26 10:15         ` Luis Machado
2024-04-20  5:57   ` Mike Galbraith
2024-04-22 13:13   ` Tobias Huschle
     [not found]   ` <CA44DAC1-B01A-4208-B9A0-D824E8178974@oracle.com>
2024-07-02 13:08     ` Peter Zijlstra
2024-04-05 10:28 ` [RFC][PATCH 09/10] sched/eevdf: Allow shorter slices to wakeup-preempt Peter Zijlstra
2024-04-05 10:28 ` [RFC][PATCH 10/10] sched/eevdf: Use sched_attr::sched_runtime to set request/slice suggestion Peter Zijlstra
2024-04-06  8:16   ` Hillf Danton
2024-05-07  5:34   ` Mike Galbraith
2024-05-15 10:13     ` Peter Zijlstra
2024-05-07 15:15   ` Chen Yu
2024-05-08 13:52     ` Mike Galbraith
2024-05-09  3:48       ` Chen Yu
2024-05-09  5:00         ` Mike Galbraith
2024-05-13  4:07     ` K Prateek Nayak
2024-05-14  9:18       ` Chen Yu
2024-05-14 15:23         ` K Prateek Nayak
2024-05-14 16:15           ` Chen Yu
2024-05-22 14:48           ` Chen Yu
2024-05-27 10:11 ` [RFC][PATCH 00/10] sched/fair: Complete EEVDF K Prateek Nayak

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