diff mbox series

arm64: dts: qcom: sm8250: correct dynamic power coefficients

Message ID 20230615154852.130076-1-vincent.guittot@linaro.org
State Accepted
Commit 775a5283c25d160b2a1359018c447bc518096547
Headers show
Series arm64: dts: qcom: sm8250: correct dynamic power coefficients | expand

Commit Message

Vincent Guittot June 15, 2023, 3:48 p.m. UTC
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>
---

Srini gave me access to sm8250 rb5 board so I checked the EM and found
that it has similar problem as sdm845.

 arch/arm64/boot/dts/qcom/sm8250.dtsi | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Bjorn Andersson July 10, 2023, 5:07 a.m. UTC | #1
On Thu, 15 Jun 2023 17:48:52 +0200, Vincent Guittot wrote:
> 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
> 
> [...]

Applied, thanks!

[1/1] arm64: dts: qcom: sm8250: correct dynamic power coefficients
      commit: 775a5283c25d160b2a1359018c447bc518096547

Best regards,
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/qcom/sm8250.dtsi b/arch/arm64/boot/dts/qcom/sm8250.dtsi
index 7bea916900e2..4b0835109b01 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";