[PATCH] arm64: dts: juno: fix cluster sleep state entry latency on all SoC versions

[PATCH] arm64: dts: juno: fix cluster sleep state entry latency on all SoC versions

[Sudeep Holla]

The core and the cluster sleep state entry latencies can't be same as
cluster sleep involves more work compared to core level e.g. shared
cache maintenance.

Experiments have shown on an average about 100us more latency for the
cluster sleep state compared to the core level sleep. This patch fixes
the entry latency for the cluster sleep state.

Fixes: 28e10a8f3a03 ("arm64: dts: juno: Add idle-states to device tree")
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: "Jon Medhurst (Tixy)" <tixy@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 arch/arm64/boot/dts/arm/juno-r1.dts | 2 +-
 arch/arm64/boot/dts/arm/juno-r2.dts | 2 +-
 arch/arm64/boot/dts/arm/juno.dts    | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

Hi,

This was found recently when I found that core sleep was chosen when
entering suspend-to-idle state on Juno. Since the wakeup(entry+exit)
latency matched for the both states, cpu sleep state was chosen to enter
in suspend-to-idle.

Regards,
Sudeep

diff --git a/arch/arm64/boot/dts/arm/juno-r1.dts b/arch/arm64/boot/dts/arm/juno-r1.dts
index 3be8a3ef671c..eec37feee8fc 100644
--- a/arch/arm64/boot/dts/arm/juno-r1.dts
+++ b/arch/arm64/boot/dts/arm/juno-r1.dts
@@ -76,7 +76,7 @@
 				compatible = "arm,idle-state";
 				arm,psci-suspend-param = <0x1010000>;
 				local-timer-stop;
-				entry-latency-us = <300>;
+				entry-latency-us = <400>;
 				exit-latency-us = <1200>;
 				min-residency-us = <2500>;
 			};
diff --git a/arch/arm64/boot/dts/arm/juno-r2.dts b/arch/arm64/boot/dts/arm/juno-r2.dts
index 614fc9227943..28f40ec44090 100644
--- a/arch/arm64/boot/dts/arm/juno-r2.dts
+++ b/arch/arm64/boot/dts/arm/juno-r2.dts
@@ -76,7 +76,7 @@
 				compatible = "arm,idle-state";
 				arm,psci-suspend-param = <0x1010000>;
 				local-timer-stop;
-				entry-latency-us = <300>;
+				entry-latency-us = <400>;
 				exit-latency-us = <1200>;
 				min-residency-us = <2500>;
 			};
diff --git a/arch/arm64/boot/dts/arm/juno.dts b/arch/arm64/boot/dts/arm/juno.dts
index 6b4135e9cfe5..ac5ceb73f45f 100644
--- a/arch/arm64/boot/dts/arm/juno.dts
+++ b/arch/arm64/boot/dts/arm/juno.dts
@@ -76,7 +76,7 @@
 				compatible = "arm,idle-state";
 				arm,psci-suspend-param = <0x1010000>;
 				local-timer-stop;
-				entry-latency-us = <300>;
+				entry-latency-us = <400>;
 				exit-latency-us = <1200>;
 				min-residency-us = <2500>;
 			};
--
2.7.4

[PATCH] arm64: dts: juno: fix cluster sleep state entry latency on all SoC versions

[Liviu Dudau]

On Mon, Nov 14, 2016 at 03:26:29PM +0000, Sudeep Holla wrote:
> The core and the cluster sleep state entry latencies can't be same as
> cluster sleep involves more work compared to core level e.g. shared
> cache maintenance.
> 
> Experiments have shown on an average about 100us more latency for the
> cluster sleep state compared to the core level sleep. This patch fixes
> the entry latency for the cluster sleep state.
> 
> Fixes: 28e10a8f3a03 ("arm64: dts: juno: Add idle-states to device tree")
> Cc: Liviu Dudau <liviu.dudau@arm.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: "Jon Medhurst (Tixy)" <tixy@linaro.org>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

Looks sensible to me.

Reviewed-by: Liviu Dudau <Liviu.Dudau@arm.com>

> ---
>  arch/arm64/boot/dts/arm/juno-r1.dts | 2 +-
>  arch/arm64/boot/dts/arm/juno-r2.dts | 2 +-
>  arch/arm64/boot/dts/arm/juno.dts    | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> Hi,
> 
> This was found recently when I found that core sleep was chosen when
> entering suspend-to-idle state on Juno. Since the wakeup(entry+exit)
> latency matched for the both states, cpu sleep state was chosen to enter
> in suspend-to-idle.
> 
> Regards,
> Sudeep
> 
> diff --git a/arch/arm64/boot/dts/arm/juno-r1.dts b/arch/arm64/boot/dts/arm/juno-r1.dts
> index 3be8a3ef671c..eec37feee8fc 100644
> --- a/arch/arm64/boot/dts/arm/juno-r1.dts
> +++ b/arch/arm64/boot/dts/arm/juno-r1.dts
> @@ -76,7 +76,7 @@
>  				compatible = "arm,idle-state";
>  				arm,psci-suspend-param = <0x1010000>;
>  				local-timer-stop;
> -				entry-latency-us = <300>;
> +				entry-latency-us = <400>;
>  				exit-latency-us = <1200>;
>  				min-residency-us = <2500>;
>  			};
> diff --git a/arch/arm64/boot/dts/arm/juno-r2.dts b/arch/arm64/boot/dts/arm/juno-r2.dts
> index 614fc9227943..28f40ec44090 100644
> --- a/arch/arm64/boot/dts/arm/juno-r2.dts
> +++ b/arch/arm64/boot/dts/arm/juno-r2.dts
> @@ -76,7 +76,7 @@
>  				compatible = "arm,idle-state";
>  				arm,psci-suspend-param = <0x1010000>;
>  				local-timer-stop;
> -				entry-latency-us = <300>;
> +				entry-latency-us = <400>;
>  				exit-latency-us = <1200>;
>  				min-residency-us = <2500>;
>  			};
> diff --git a/arch/arm64/boot/dts/arm/juno.dts b/arch/arm64/boot/dts/arm/juno.dts
> index 6b4135e9cfe5..ac5ceb73f45f 100644
> --- a/arch/arm64/boot/dts/arm/juno.dts
> +++ b/arch/arm64/boot/dts/arm/juno.dts
> @@ -76,7 +76,7 @@
>  				compatible = "arm,idle-state";
>  				arm,psci-suspend-param = <0x1010000>;
>  				local-timer-stop;
> -				entry-latency-us = <300>;
> +				entry-latency-us = <400>;
>  				exit-latency-us = <1200>;
>  				min-residency-us = <2500>;
>  			};
> --
> 2.7.4
> 

-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
    ?\_(?)_/?