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Date:   Mon, 6 Nov 2023 22:52:22 +0100
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Subject: Re: [PATCH v2] arm64: dts: qcom: sc7280: Add capacity and DPC
 properties
To:     Doug Anderson <dianders@chromium.org>
Cc:     Ankit Sharma <quic_anshar@quicinc.com>,
        cros-qcom-dts-watchers@chromium.org, agross@kernel.org,
        andersson@kernel.org, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, quic_ashayj@quicinc.com,
        quic_atulpant@quicinc.com, quic_rgottimu@quicinc.com,
        quic_shashim@quicinc.com, quic_pkondeti@quicinc.com
References: <20231103105440.23904-1-quic_anshar@quicinc.com>
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From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <CAD=FV=VTCXSQo3Bo3G7oJ48qA-fUet5rHAzT8WLM1Hx70KyYMA@mail.gmail.com>
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On 11/6/23 17:56, Doug Anderson wrote:
> Hi,
> 
> On Sat, Nov 4, 2023 at 4:52 AM Konrad Dybcio <konrad.dybcio@linaro.org> wrote:
>>
>>
>>
>> On 11/3/23 11:54, Ankit Sharma wrote:
>>> The "capacity-dmips-mhz" and "dynamic-power-coefficient" are
>>> used to build Energy Model which in turn is used by EAS to take
>>> placement decisions. So add it to SC7280 soc.
>>>
>>> Signed-off-by: Ankit Sharma <quic_anshar@quicinc.com>
>>> ---Hi, thanks for this patch
>>
>> Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
>>
>> I performed a quick grep in arch/arm64/boot/dts/qcom and noticed
>> that at least one of these values is missing for:
>>
>> rg -l --files-without-match dynamic-power-coeff $(rg cpu@ -l) | sort
>> ipq5018.dtsi (homogeneous cluster)
>> ipq5332.dtsi (homogeneous cluster)
>> ipq6018.dtsi (homogeneous cluster)
>> ipq8074.dtsi (homogeneous cluster)
>> ipq9574.dtsi (homogeneous cluster)
>> msm8916.dtsi (homogeneous cluster)
>> msm8939.dtsi
>> msm8953.dtsi
>> msm8976.dtsi
>> msm8994.dtsi
>> msm8996.dtsi
>> msm8998.dtsi
>> qcs404.dtsi (homogeneous cluster)
>> qdu1000.dtsi (homogeneous cluster)
>> sa8775p.dtsi
>> sc7280.dtsi
>> sc8180x.dtsi
>> sc8280xp.dtsi
>> sdm630.dtsi
>> sm4450.dtsi
>> sm6125.dtsi
>> sm6375.dtsi
>> sm8350.dtsi
>> sm8450.dtsi
>>
>> rg -l --files-without-match capacity-dmips $(rg cpu@ -l) | sort
>> ipq5018.dtsi (homogeneous cluster)
>> ipq5332.dtsi (homogeneous cluster)
>> ipq6018.dtsi (homogeneous cluster)
>> ipq8074.dtsi (homogeneous cluster)
>> ipq9574.dtsi (homogeneous cluster)
>> msm8916.dtsi (homogeneous cluster)
>> msm8939.dtsi
>> msm8994.dtsi
>> qcs404.dtsi (homogeneous cluster)
>> qdu1000.dtsi (homogeneous cluster)
>> sa8775p.dtsi
>> sc7280.dtsi
>> sm4450.dtsi
>> sm6375.dtsi
>> sm8350.dtsi
>> sm8450.dtsi
>>
>> Where platforms with a single, homogeneous cluster likely don't
>> benefit from EAS..
>>
>> Is there any chance you could dig up the correct values, for at least
>> some of these platforms? Or would you know whom to ask?
>>
>> FWIW the one we're missing the most is sc8280xp..
> 
> FWIW, I wrote up a longwinded commit message when I added these values
> for sc7180. See commit 82ea7d411d43 ("arm64: dts: qcom: sc7180: Base
> dynamic CPU power coefficients in reality").
> 
> The short of it is that if you have hardware and a basic "smart
> battery" to measure power consumption it's pretty easy for anyone to
> add some reasonable numbers.
That's a big ask, especially with stupid laptop battmgr firmware that
only refreshes data every 5 to 25 seconds :)

Qcom probably has some reasonable numbers somewhere, given they are
likely to test their SoCs' characteristics before taping them out
en masse :P

Konrad