From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Hongyan Xia <hongyan.xia2@arm.com>, Xuewen Yan <xuewen.yan94@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Lukasz Luba <lukasz.luba@arm.com>,
Christian Loehle <christian.loehle@arm.com>,
Pierre Gondois <pierre.gondois@arm.com>,
linux-kernel@vger.kernel.org, Xuewen Yan <xuewen.yan@unisoc.com>
Subject: Re: [PATCH v2 0/8] uclamp sum aggregation
Date: Mon, 10 Mar 2025 16:37:37 +0100 [thread overview]
Message-ID: <a5ea2f23-4b87-41d6-9dae-9ddc94024d6f@arm.com> (raw)
In-Reply-To: <4a8ed999-2ee5-478c-a759-fec1c496cba9@arm.com>
On 10/03/2025 13:54, Hongyan Xia wrote:
> On 10/03/2025 11:34, Dietmar Eggemann wrote:
>> On 06/03/2025 12:38, Xuewen Yan wrote:
>>> On Thu, Mar 6, 2025 at 7:32 PM Hongyan Xia <hongyan.xia2@arm.com> wrote:
>>>>
>>>> Hi Xuewen,
>>>>
>>>> On 06/03/2025 11:12, Xuewen Yan wrote:
>>>>> Hi Hongyan,
>>>>>
>>>>> On Tue, Mar 4, 2025 at 10:26 PM Hongyan Xia <hongyan.xia2@arm.com>
[...]
>> Like I mentioned already in the original thread:
>>
>> https://lkml.kernel.org/r/65365ec7-6a16-4e66-8005-e78788cbedfa@arm.com
>>
>> I would prefer that uclamp stays in core.c. ENQUEUE_DELAYED among all
>> the other flags is already used there (ttwu_runnable()).
>>
>> task_struct contains sched_{,rt_,dl_}entity}. We just have to be
>> careful when switching policies.
>>
>> --
>>
>> Could you also incorporate the changes in {en,de}queue_task_fair()
>> ((task_on_rq_migrating(p) || (flags & {RESTORE,DEQUEUE}_SAVE))) vs.
>> (!p->se.sched_delayed || (flags & ENQUEUE_DELAYED)) and
>> (!p->se.sched_delayed) so the uclamp-util_est relation is easier to spot?
>>
>> [...]
>
> At the moment we can't do this. Sum aggregation was designed before
> delayed dequeue and it syncs with p->se.on_rq. If we sync with something
> else and take care of delayed dequeue cases (like util_est) then I have
> to rewrite part of the series.
Ah, OK! But this 'uclamp not in sync with util_est' is already an issue
on today's mainline so I would like to see this fixed as discreet as
possible and then another prep-patch for 'uclamp sum aggregation'.
IMHO, then it's clearer why we would need more rework in this area.
prev parent reply other threads:[~2025-03-10 15:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-04 14:23 [PATCH v2 0/8] uclamp sum aggregation Hongyan Xia
2025-03-04 14:23 ` [PATCH v2 1/8] Revert "sched/uclamp: Set max_spare_cap_cpu even if max_spare_cap is 0" Hongyan Xia
2025-03-04 14:23 ` [PATCH v2 2/8] sched/uclamp: Track a new util_avg_bias signal Hongyan Xia
2025-03-04 14:23 ` [PATCH v2 3/8] sched/uclamp: Add util_est_uclamp Hongyan Xia
2025-03-04 14:23 ` [PATCH v2 4/8] sched/fair: Use util biases for utilization and frequency Hongyan Xia
2025-03-04 14:23 ` [PATCH v2 5/8] sched/uclamp: Remove all uclamp bucket logic Hongyan Xia
2025-03-04 14:23 ` [PATCH v2 6/8] sched/uclamp: Simplify uclamp_eff_value() Hongyan Xia
2025-03-04 14:23 ` [PATCH v2 7/8] sched/uclamp: Propagate negative bias Hongyan Xia
2025-03-04 14:23 ` [PATCH v2 8/8] sched/uclamp: Solve under-utilization problem Hongyan Xia
2025-03-06 11:12 ` [PATCH v2 0/8] uclamp sum aggregation Xuewen Yan
2025-03-06 11:32 ` Hongyan Xia
2025-03-06 11:38 ` Xuewen Yan
2025-03-10 11:34 ` Dietmar Eggemann
2025-03-10 12:54 ` Hongyan Xia
2025-03-10 15:37 ` Dietmar Eggemann [this message]
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