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
prev 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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