Am Dienstag, 25. Juli 2017, 17:22:55 CEST schrieb Caesar Wang:
> This patch updates the dynamic-power-coefficient for big cluster on
> rk3399 SoCs.
>
> The dynamic power consumption of the CPU is proportional to the square of
> the Voltage (V) and the clock frequency (f). The coefficient is used to
> calculate the dynamic power as below -
> Pdyn = dynamic-power-coefficient * V^2 * f
> Where Voltage is in uV, frequency is in MHz.
>
> As the following is the tested data on rk3399's big cluster.
> frequency(MHz) Voltage(V) Current(mA) Dynamic-power-coefficient
> 24 0.8 15
> 48 0.8 23 ~417
> 96 0.8 40 ~443
> 216 0.8 82 ~438
> 312 0.8 115 ~430
> 408 0.8 150 ~455
> So the dynamic-power-coefficient average value is about 436.
>
> Signed-off-by: Caesar Wang <[email protected]>
applied for 4.14 and thanks for that very nice and informative commit
message explaining the testing methodology.
Heiko
> ---
>
> arch/arm64/boot/dts/rockchip/rk3399.dtsi | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> index 9d02006..5d54a06 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> @@ -150,7 +150,7 @@
> enable-method = "psci";
> #cooling-cells = <2>; /* min followed by max */
> clocks = <&cru ARMCLKB>;
> - dynamic-power-coefficient = <100>;
> + dynamic-power-coefficient = <436>;
> };
>
> cpu_b1: cpu@101 {
> @@ -159,7 +159,7 @@
> reg = <0x0 0x101>;
> enable-method = "psci";
> clocks = <&cru ARMCLKB>;
> - dynamic-power-coefficient = <100>;
> + dynamic-power-coefficient = <436>;
> };
> };
>
>
