linux-kernel - Re: [PATCH v1 4/6] arm64: dts: exynos: gs101: Add 'local-timer-stop' to cpuidle nodes

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Message-ID: <Z+y4zxfifkQqLxKF@perf>
Date: Wed, 2 Apr 2025 13:10:55 +0900
From: Youngmin Nam <youngmin.nam@...sung.com>
To: Will McVicker <willmcvicker@...gle.com>
Cc: Catalin Marinas <catalin.marinas@....com>, Will Deacon
	<will@...nel.org>, Peter Griffin <peter.griffin@...aro.org>,
	André Draszik <andre.draszik@...aro.org>, Tudor Ambarus
	<tudor.ambarus@...aro.org>, Rob Herring <robh@...nel.org>, Krzysztof
	Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Alim
	Akhtar <alim.akhtar@...sung.com>, Daniel Lezcano
	<daniel.lezcano@...aro.org>, Thomas Gleixner <tglx@...utronix.de>, Saravana
	Kannan <saravanak@...gle.com>, Will McVicker <willmcvicker@...gle.com>,
	kernel-team@...roid.com, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	devicetree@...r.kernel.org, Will Deacon <willdeacon@...gle.com>
Subject: Re: [PATCH v1 4/6] arm64: dts: exynos: gs101: Add
 'local-timer-stop' to cpuidle nodes

On Mon, Mar 31, 2025 at 04:00:26PM -0700, Will McVicker wrote:
> From: Will Deacon <willdeacon@...gle.com>
> 
> In preparation for switching to the architected timer as the primary
> clockevents device, mark the cpuidle nodes with the 'local-timer-stop'
> property to indicate that an alternative clockevents device must be
> used for waking up from the "c2" idle state.
> 
> Signed-off-by: Will Deacon <willdeacon@...gle.com>
> [Original commit from https://android.googlesource.com/kernel/gs/+/a896fd98638047989513d05556faebd28a62b27c]
> Signed-off-by: Will McVicker <willmcvicker@...gle.com>
> ---
>  arch/arm64/boot/dts/exynos/google/gs101.dtsi | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/exynos/google/gs101.dtsi b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> index 3de3a758f113..fd0badf24e6f 100644
> --- a/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> +++ b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> @@ -155,6 +155,7 @@ ananke_cpu_sleep: cpu-ananke-sleep {
>  				idle-state-name = "c2";
>  				compatible = "arm,idle-state";
>  				arm,psci-suspend-param = <0x0010000>;
> +				local-timer-stop;
>  				entry-latency-us = <70>;
>  				exit-latency-us = <160>;
>  				min-residency-us = <2000>;
> @@ -164,6 +165,7 @@ enyo_cpu_sleep: cpu-enyo-sleep {
>  				idle-state-name = "c2";
>  				compatible = "arm,idle-state";
>  				arm,psci-suspend-param = <0x0010000>;
> +				local-timer-stop;
>  				entry-latency-us = <150>;
>  				exit-latency-us = <190>;
>  				min-residency-us = <2500>;
> @@ -173,6 +175,7 @@ hera_cpu_sleep: cpu-hera-sleep {
>  				idle-state-name = "c2";
>  				compatible = "arm,idle-state";
>  				arm,psci-suspend-param = <0x0010000>;
> +				local-timer-stop;
>  				entry-latency-us = <235>;
>  				exit-latency-us = <220>;
>  				min-residency-us = <3500>;
> -- 
> 2.49.0.472.ge94155a9ec-goog
> 
Hi Will.

Are you using this property in production?
If so, have you noticed any performance improvements?

Thanks.
Youngmin