6.4-stable review patch. If anyone has any objections, please let me know.
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From: Vincent Guittot vincent.guittot@linaro.org
[ Upstream commit 775a5283c25d160b2a1359018c447bc518096547 ]
sm8250 faces the same problem with its Energy Model as sdm845. The energy cost of LITTLE cores is reported to be higher than medium or big cores
EM computes the energy with formula:
energy = OPP's cost / maximum cpu capacity * utilization
On v6.4-rc6 we have: max capacity of CPU0 = 284 capacity of CPU0's OPP(1612800 Hz) = 253 cost of CPU0's OPP(1612800 Hz) = 191704
max capacity of CPU4 = 871 capacity of CPU4's OPP(710400 Hz) = 255 cost of CPU4's OPP(710400 Hz) = 343217
Both OPPs have almost the same compute capacity but the estimated energy per unit of utilization will be estimated to:
energy CPU0 = 191704 / 284 * 1 = 675 energy CPU4 = 343217 / 871 * 1 = 394
EM estimates that little CPU0 will consume 71% more than medium CPU4 for the same compute capacity. According to [1], little consumes 25% less than medium core for Coremark benchmark at those OPPs for the same duration.
Set the dynamic-power-coefficient of CPU0-3 to 105 to fix the energy model for little CPUs.
[1] https://github.com/kdrag0n/freqbench/tree/master/results/sm8250/k30s
Fixes: 6aabed5526ee ("arm64: dts: qcom: sm8250: Add CPU capacities and energy model") Signed-off-by: Vincent Guittot vincent.guittot@linaro.org Link: https://lore.kernel.org/r/20230615154852.130076-1-vincent.guittot@linaro.org Signed-off-by: Bjorn Andersson andersson@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/boot/dts/qcom/sm8250.dtsi | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/boot/dts/qcom/sm8250.dtsi b/arch/arm64/boot/dts/qcom/sm8250.dtsi index 7bea916900e29..4b0835109b01e 100644 --- a/arch/arm64/boot/dts/qcom/sm8250.dtsi +++ b/arch/arm64/boot/dts/qcom/sm8250.dtsi @@ -100,7 +100,7 @@ CPU0: cpu@0 { clocks = <&cpufreq_hw 0>; enable-method = "psci"; capacity-dmips-mhz = <448>; - dynamic-power-coefficient = <205>; + dynamic-power-coefficient = <105>; next-level-cache = <&L2_0>; power-domains = <&CPU_PD0>; power-domain-names = "psci"; @@ -131,7 +131,7 @@ CPU1: cpu@100 { clocks = <&cpufreq_hw 0>; enable-method = "psci"; capacity-dmips-mhz = <448>; - dynamic-power-coefficient = <205>; + dynamic-power-coefficient = <105>; next-level-cache = <&L2_100>; power-domains = <&CPU_PD1>; power-domain-names = "psci"; @@ -156,7 +156,7 @@ CPU2: cpu@200 { clocks = <&cpufreq_hw 0>; enable-method = "psci"; capacity-dmips-mhz = <448>; - dynamic-power-coefficient = <205>; + dynamic-power-coefficient = <105>; next-level-cache = <&L2_200>; power-domains = <&CPU_PD2>; power-domain-names = "psci"; @@ -181,7 +181,7 @@ CPU3: cpu@300 { clocks = <&cpufreq_hw 0>; enable-method = "psci"; capacity-dmips-mhz = <448>; - dynamic-power-coefficient = <205>; + dynamic-power-coefficient = <105>; next-level-cache = <&L2_300>; power-domains = <&CPU_PD3>; power-domain-names = "psci";