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From: Tejun Heo <tj@kernel.org>
To: Xuewen Yan <xuewen.yan@unisoc.com>
Cc: peterz@infradead.org, mingo@redhat.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	vschneid@redhat.com, lukasz.luba@arm.com,
	linux-kernel@vger.kernel.org, rui.zhang@intel.com,
	di.shen@unisoc.com, ke.wang@unisoc.com, xuewen.yan94@gmail.com
Subject: Re: [RFC PATCH] sched: Add scx_cpuperf_target in sched_cpu_util()
Date: Wed, 18 Mar 2026 15:21:10 -1000	[thread overview]
Message-ID: <abtPhrLCzq6SpXSc@slm.duckdns.org> (raw)
In-Reply-To: <20260318121755.16354-1-xuewen.yan@unisoc.com>

On Wed, Mar 18, 2026 at 08:17:55PM +0800, Xuewen Yan wrote:
> Recently, while enabling sched-ext debugging, we observed abnormal behavior
> in our thermal power_allocator’s temperature control.
> Through debugging, we found that the CPU util was too low, causing
> the CPU frequency to remain unrestricted.
> 
> This issue stems from the fact that in the sched_cpu_util() function,
> when scx is enabled, cpu_util_cfs becomes zero. As a result,
> the thermal subsystem perceives an extremely low CPU utilization,
> which degrades the effectiveness of the power_allocator’s control.
> 
> To address this, we propose adding scx_cpuperf_target in the sched_cpu_util()
> as a replacement for cpu_util_cfs, ensuring that the thermal subsystem receives
> accurate load information and restores proper control behavior.
> 
> Reported-by: Di Shen <di.shen@unisoc.com>
> Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>

Yeah, I missed that path. In either this or Peter's suggested form:

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

      parent reply	other threads:[~2026-03-19  1:21 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-18 12:17 [RFC PATCH] sched: Add scx_cpuperf_target in sched_cpu_util() Xuewen Yan
2026-03-18 12:47 ` Peter Zijlstra
2026-03-18 12:55   ` Vincent Guittot
2026-03-18 13:44     ` Qais Yousef
2026-03-19  2:13       ` Xuewen Yan
2026-03-19  7:09         ` Vincent Guittot
2026-03-19 10:18         ` Lukasz Luba
2026-03-24  1:32         ` Qais Yousef
2026-03-18 13:03   ` [PATCH] sched/cpufreq: Reorder so non-SCX is common path Christian Loehle
2026-03-19  1:08   ` [RFC PATCH] sched: Add scx_cpuperf_target in sched_cpu_util() Tejun Heo
2026-03-19  2:24     ` Xuewen Yan
2026-03-19  2:38       ` Xuewen Yan
2026-03-19  9:02     ` Peter Zijlstra
2026-03-19 10:01       ` Uros Bizjak
2026-03-19 10:26         ` Peter Zijlstra
2026-03-19 11:02           ` Uros Bizjak
2026-03-19 11:12             ` Peter Zijlstra
2026-03-19 11:19               ` Uros Bizjak
2026-03-19 11:33                 ` Peter Zijlstra
2026-03-19 11:22               ` Peter Zijlstra
2026-03-18 12:54 ` Christian Loehle
2026-03-19  1:21 ` Tejun Heo [this message]

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