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Date:   Sun, 8 Jul 2018 22:01:57 +0800
From:   leo.yan@linaro.org
To:     Vincent Guittot <vincent.guittot@linaro.org>
Cc:     xuwei5@hisilicon.com, robh+dt@kernel.org,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, daniel.lezcano@linaro.org
Subject: Re: [PATCH] arm64: hikey960: update idle-states
Message-ID: <20180708140157.GA28878@leoy-ThinkPad-X240s>
References: <1530860246-29072-1-git-send-email-vincent.guittot@linaro.org>
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Hi Vincent,

On Fri, Jul 06, 2018 at 08:57:26AM +0200, Vincent Guittot wrote:
> Update entry/exit latency and residency time of hikey960 to use more
> realistic figures based on unitary tests done on the platform.
> 
> The complete results (in us) :
>                   big cluster
>                   cluster  CPU
> max entry latency     800  400
> max exit latency     2900  550
> residency  903Mhz    5000 1500
> residency 2363Mhz       0 1500
> 
>                   little cluster
>                   cluster  CPU
> max entry latency     500  400
> max exit latency     1600  650
> residency  533Mhz    8000 4500
> residency 1844Mhz       0 1500
> 
> We can see that the residency time depends of the running OPP which is not
> handled for now. Then we also have to take into account the constraint of
> a residency time shorter than the tick to get full advantage of idle loop
> reordering(tick is stopped if idle duration is higher than tick period).
> Finally the selected residency value are :
>                  big cluster
>                   cluster  CPU
> residency            3700 1500
> 
>                   little cluster
>                   cluster  CPU
> residency            3500 1500
> 
> A simple test with a task waking up every 11,111ms shows improvement:

Should s/11,111ms/11.111ms ?

> - 5% a lowest OPP
> - 22% at highest OPP
> 
> The period has been chosen:
> - to be shorter than old cluster residency time and longer than new
> residency time od cluster off C-state

Should s/od/of/ ?

Except these two minor typos, the patch is very good improvement.

Reviewed-by: Leo Yan <leo.yan@linaro.org>

> - to prevent any sync with tick (4ms) when running tests that can add
> some variances between tests
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
>  arch/arm64/boot/dts/hisilicon/hi3660.dtsi | 45 ++++++++++++++++++-------------
>  1 file changed, 27 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/hisilicon/hi3660.dtsi b/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> index 421d454..890d23e 100644
> --- a/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> +++ b/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> @@ -61,7 +61,7 @@
>  			reg = <0x0 0x0>;
>  			enable-method = "psci";
>  			next-level-cache = <&A53_L2>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_0>;
> +			cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
>  			capacity-dmips-mhz = <592>;
>  			clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER0>;
>  			operating-points-v2 = <&cluster0_opp>;
> @@ -75,7 +75,7 @@
>  			reg = <0x0 0x1>;
>  			enable-method = "psci";
>  			next-level-cache = <&A53_L2>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_0>;
> +			cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
>  			capacity-dmips-mhz = <592>;
>  			clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER0>;
>  			operating-points-v2 = <&cluster0_opp>;
> @@ -87,7 +87,7 @@
>  			reg = <0x0 0x2>;
>  			enable-method = "psci";
>  			next-level-cache = <&A53_L2>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_0>;
> +			cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
>  			capacity-dmips-mhz = <592>;
>  			clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER0>;
>  			operating-points-v2 = <&cluster0_opp>;
> @@ -99,7 +99,7 @@
>  			reg = <0x0 0x3>;
>  			enable-method = "psci";
>  			next-level-cache = <&A53_L2>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_0>;
> +			cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
>  			capacity-dmips-mhz = <592>;
>  			clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER0>;
>  			operating-points-v2 = <&cluster0_opp>;
> @@ -111,7 +111,7 @@
>  			reg = <0x0 0x100>;
>  			enable-method = "psci";
>  			next-level-cache = <&A73_L2>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_1>;
> +			cpu-idle-states = <&CPU_SLEEP_1 &CLUSTER_SLEEP_1>;
>  			capacity-dmips-mhz = <1024>;
>  			clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER1>;
>  			operating-points-v2 = <&cluster1_opp>;
> @@ -125,7 +125,7 @@
>  			reg = <0x0 0x101>;
>  			enable-method = "psci";
>  			next-level-cache = <&A73_L2>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_1>;
> +			cpu-idle-states = <&CPU_SLEEP_1 &CLUSTER_SLEEP_1>;
>  			capacity-dmips-mhz = <1024>;
>  			clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER1>;
>  			operating-points-v2 = <&cluster1_opp>;
> @@ -137,7 +137,7 @@
>  			reg = <0x0 0x102>;
>  			enable-method = "psci";
>  			next-level-cache = <&A73_L2>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_1>;
> +			cpu-idle-states = <&CPU_SLEEP_1 &CLUSTER_SLEEP_1>;
>  			capacity-dmips-mhz = <1024>;
>  			clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER1>;
>  			operating-points-v2 = <&cluster1_opp>;
> @@ -149,7 +149,7 @@
>  			reg = <0x0 0x103>;
>  			enable-method = "psci";
>  			next-level-cache = <&A73_L2>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_1>;
> +			cpu-idle-states = <&CPU_SLEEP_1 &CLUSTER_SLEEP_1>;
>  			capacity-dmips-mhz = <1024>;
>  			clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER1>;
>  			operating-points-v2 = <&cluster1_opp>;
> @@ -158,31 +158,40 @@
>  		idle-states {
>  			entry-method = "psci";
>  
> -			CPU_SLEEP: cpu-sleep {
> +			CPU_SLEEP_0: cpu-sleep-0 {
>  				compatible = "arm,idle-state";
>  				local-timer-stop;
>  				arm,psci-suspend-param = <0x0010000>;
> -				entry-latency-us = <40>;
> -				exit-latency-us = <70>;
> -				min-residency-us = <3000>;
> +				entry-latency-us = <400>;
> +				exit-latency-us = <650>;
> +				min-residency-us = <1500>;
>  			};
> -
>  			CLUSTER_SLEEP_0: cluster-sleep-0 {
>  				compatible = "arm,idle-state";
>  				local-timer-stop;
>  				arm,psci-suspend-param = <0x1010000>;
>  				entry-latency-us = <500>;
> -				exit-latency-us = <5000>;
> -				min-residency-us = <20000>;
> +				exit-latency-us = <1600>;
> +				min-residency-us = <3500>;
> +			};
> +
> +
> +			CPU_SLEEP_1: cpu-sleep-1 {
> +				compatible = "arm,idle-state";
> +				local-timer-stop;
> +				arm,psci-suspend-param = <0x0010000>;
> +				entry-latency-us = <400>;
> +				exit-latency-us = <550>;
> +				min-residency-us = <1500>;
>  			};
>  
>  			CLUSTER_SLEEP_1: cluster-sleep-1 {
>  				compatible = "arm,idle-state";
>  				local-timer-stop;
>  				arm,psci-suspend-param = <0x1010000>;
> -				entry-latency-us = <1000>;
> -				exit-latency-us = <5000>;
> -				min-residency-us = <20000>;
> +				entry-latency-us = <800>;
> +				exit-latency-us = <2900>;
> +				min-residency-us = <3500>;
>  			};
>  		};
>  
> -- 
> 2.7.4
>