Hi Oliver,
On 07/20/2018 04:15 PM, Oliver Effland wrote:
Hello everyone,
I hope this is the right place to ask, otherwise please just point me in the right direction.
I'm currently testing the EAS patches [v4] on an ODROID-XU3 board, which has an Exynos5422 SoC. However, the corresponding DT is missing the "dynamic-power-coefficient" that is needed for an appropriate EM. So I'm trying to compute the dynamic-power-coefficient according to the formula:
Pdyn = dynamic-power-coefficient * V^2 * f
The frequency f is given by the DT.The actual Voltage and Power are determined by means of the on-chip sensors (returns the values for the specific cluster). When using the Voltage given in the DT, the differences for the d-p-coefficient are negligible.
So I'm calculating the d-p-coefficient (mW/MHz/uV^2) by reading out the following SoC sensor values.
For the little cluster (A7): frequency(MHz) Voltage(V) Power(mW) Dynamic-power-coefficient 200 0.9175 49.470 ~2.938*10^-13 400 0.9165 91.892 ~2.736*10^-13 600 0.9638 149.454 ~2.682*10^-13 800 1.0263 223.453 ~2.652*10^-13 1000 1.1000 327.707 ~2.708*10^-13 1200 1.1725 445.899 ~2.703*10^-13 1400 1.2713 627.010 ~2.771*10^-13
For the big cluster (A15): frequency(MHz) Voltage(V) Power(mW) Dynamic-power-coefficient 200 0.9162 159.676 ~9.510*10^-13 500 0.9138 325.480 ~7.797*10^-13 800 0.9288 511.360 ~7.410*10^-13 1100 1.0063 828.020 ~7.434*10^-13 1400 1.0713 1209.774 ~7.530*10^-13 1700 1.1750 1835.784 ~7.822*10^-13 2000 1.2700 2661.849 ~8.252*10^-13
We do support Arm's TC2 platform (2xA15 and 3xA7) with the EAS project. The latest EAS mainline integration includes Quentin's "[RFC PATCH v4 00/12] Energy Aware Scheduling" https://lkml.org/lkml/2018/6/28/301 .
You can find the appropriate patch for TC2 dynamic-power-coefficient integration "arm: dts: vexpress-v2p-ca15_a7: Add dynamic-power-coefficient properties" under https://developer.arm.com/open-source/energy-aware-scheduling/eas-mainline-d... . Follow the 'eas/next/integration' link. The patch header has a little bit of documentation about how we did it. We used the build-in TC2 Energy Meter.
This is all in sync with what Russel and Steve posted on this thread before.
Thanks for taking EAS for a spin on another Arm 32bit machine!
-- Dietmar
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