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4daa001a17
A CPUfreq driver, like the scpi driver used on Juno boards, which
provide the Energy Model with power cost information via the PM_OPP
of_dev_pm_opp_get_cpu_power() function, do need the
dynamic-power-coefficient (C) in the device tree.
Method used to obtain the C value:
C is computed by measuring energy (E) consumption of a frequency domain
(FD) over a 10s runtime (t) sysbench workload running at each Operating
Performance Point (OPP) affine to 1 or 2 CPUs of that FD while the other
CPUs of the system are hotplugged out.
By definition all CPUs of a FD have the the same micro-architecture. An
OPP is characterized by a certain frequency (f) and voltage (V) value.
The corresponding power values (P) are calculated by dividing the delta
of the E values between the runs with 2 and 1 CPUs by t.
With n data tuples (P, f, V), n equal to number of OPPs for this
frequency domain, we can solve C by:
P = Pstat + Pdyn
P = Pstat + CV²f
Cx = (Px - P1)/(Vx²fx - V1²f1) with x = {2, ..., n}
The C value is the arithmetic mean out of {C2, ..., Cn}.
Since DVFS is broken on Juno r1, no dynamic-power-coefficient
information has been added to its dts file.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
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| .. | ||
| foundation-v8-gicv2.dtsi | ||
| foundation-v8-gicv3-psci.dts | ||
| foundation-v8-gicv3.dts | ||
| foundation-v8-gicv3.dtsi | ||
| foundation-v8-psci.dts | ||
| foundation-v8-psci.dtsi | ||
| foundation-v8-spin-table.dtsi | ||
| foundation-v8.dts | ||
| foundation-v8.dtsi | ||
| fvp-base-revc.dts | ||
| juno-base.dtsi | ||
| juno-clocks.dtsi | ||
| juno-cs-r1r2.dtsi | ||
| juno-motherboard.dtsi | ||
| juno-r1.dts | ||
| juno-r2.dts | ||
| juno.dts | ||
| Makefile | ||
| rtsm_ve-aemv8a.dts | ||
| rtsm_ve-motherboard-rs2.dtsi | ||
| rtsm_ve-motherboard.dtsi | ||
| vexpress-v2f-1xv7-ca53x2.dts | ||
| vexpress-v2m-rs1.dtsi | ||