Re: [PATCH] arm64: rk3399: Add capacity-dmips-mhz attributes
From: Robin Murphy <robin.murphy@arm.com>
Date: 2019-02-24 20:08:02
Also in:
linux-rockchip
Hi Marc, On 2019-02-24 2:35 pm, Marc Zyngier wrote:
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The RK3399 has the interesting property to be a so called "big-little" system, where not all the CPUs are equal (the A53s are much weaker than the A72s). So far, we're not telling the OS that there is such a difference in processing capacity, and Linux assumes that they are equal. Too bad. Let's tell the OS about this by using the capacity-dmips-mhz property. The values used here are those used on the Juno platform, which is quite similar. This leads to the scheduler knowing that it can pack more tasks on the A72s, and leads to a better interactive experience. Signed-off-by: Marc Zyngier <redacted> --- arch/arm64/boot/dts/rockchip/rk3399.dtsi | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi index 6cc1c9fa4ea6..7eab31184aee 100644 --- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi +++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi@@ -75,6 +75,7 @@ #cooling-cells = <2>; /* min followed by max */ dynamic-power-coefficient = <100>; cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>; + capacity-dmips-mhz = <578>;
Probably better to use the value from Juno r2 (485) which should more appropriately represent A53 vs. A72, rather than A53 vs. A57.
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}; cpu_l1: cpu@1 {@@ -86,6 +87,7 @@ #cooling-cells = <2>; /* min followed by max */ dynamic-power-coefficient = <100>; cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>; + capacity-dmips-mhz = <578>; }; cpu_l2: cpu@2 {@@ -97,6 +99,7 @@ #cooling-cells = <2>; /* min followed by max */ dynamic-power-coefficient = <100>; cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>; + capacity-dmips-mhz = <578>; }; cpu_l3: cpu@3 {@@ -108,6 +111,7 @@ #cooling-cells = <2>; /* min followed by max */ dynamic-power-coefficient = <100>; cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>; + capacity-dmips-mhz = <578>; }; cpu_b0: cpu@100 {@@ -118,7 +122,7 @@ clocks = <&cru ARMCLKB>; #cooling-cells = <2>; /* min followed by max */ dynamic-power-coefficient = <436>; - cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
Oops. Otherwise, though, I was on the verge of tackling this myself now that my 3399 board is building its own kernels - annoyance at the linking bottleneck steadfastly refusing to move off CPU0 (except occasionally to another little core) has been growing steadily :) With the nits fixed, Tested-by: Robin Murphy <robin.murphy@arm.com> Cheers, Robin.
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+ capacity-dmips-mhz = <1024>; }; cpu_b1: cpu@101 {@@ -130,6 +134,7 @@ #cooling-cells = <2>; /* min followed by max */ dynamic-power-coefficient = <436>; cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>; + capacity-dmips-mhz = <1024>; }; idle-states {
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