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Date: Tue, 12 Jan 2021 20:04:53 +0100
From: AngeloGioacchino Del Regno
<angelogioacchino.delregno@...ainline.org>
To: Alexey Minnekhanov <alexey.min@...il.com>,
Danny Lin <danny@...ag0n.dev>
Cc: Andy Gross <agross@...nel.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org,
Alexey Minekhanov <alexeymin@...tmarketos.org>
Subject: Re: [PATCH] arm64: dts: qcom: sdm660: Fix CPU capacities
Il 12/01/21 15:59, Alexey Minnekhanov ha scritto:
> Hi!
> I always had a feeling something is not right in those cpu
> definitions, so cpus with reg 100-103 are little cores, and 0-3 big
> ones?
> But downstream sdm660.dtsi has a property "efficiency" [1] with values
> which are larger for cores 100-103 than for 0-3 cores (1638 > 1024),
> I'm confused...
All the SDM630, SDM636 and SDM660 smartphones I ever saw are booting off
of the BIG cluster (and that's why cpu@100 is CPU0), and at 0x100 you
find the first BIG CPU.
>
> Property "efficiency" is described in the same tree in [2].
>
> [1] https://source.codeaurora.org/quic/la/kernel/msm-4.4/tree/arch/arm/boot/dts/qcom/sdm660.dtsi?h=LA.UM.7.2.c25#n155
> [2] https://source.codeaurora.org/quic/la/kernel/msm-4.4/tree/Documentation/devicetree/bindings/arm/cpus.txt?h=LA.UM.7.2.c25#n216
>
> вт, 12 янв. 2021 г. в 13:51, Danny Lin <danny@...ag0n.dev>:
>>
>> sdm660 has a big.LITTLE 4+4 CPU setup with CPUs 0-3 being little cores
>> and CPUs 4-7 being big cores. The big cores have higher IPC, so they
>> should have the higher capacity-dmips-mhz, not the other way around as
>> the device tree currently describes it. Fix the incorrect CPU map to
>> improve EAS scheduling behavior.
>>
>> While we're at it, let's replace the old DMIPS/MHz values with new
>> measurements that reflect the exact IPC of the CPUs as reported by
>> CoreMark.
>>
>> Performance measurements were made using my freqbench [1]
>> benchmark coordinator, which isolates, offlines, and disables the timer
>> tick on test CPUs to maximize accuracy. It uses EEMBC CoreMark [2] as
>> the workload and measures power usage using the PM660 PMIC's fuel
>> gauge.
>>
>> Normalized DMIPS/MHz capacity scale values for each CPU were calculated
>> from CoreMarks/MHz (CoreMark iterations per second per MHz), which
>> serves the same purpose. For each CPU, the final capacity-dmips-mhz
>> value is the C/MHz value of its maximum frequency normalized to
>> SCHED_CAPACITY_SCALE (1024) for the fastest CPU in the system.
>>
>> A Xiaomi Redmi Note 7 device running a downstream Qualcomm 4.4 kernel
>> was used for benchmarking to ensure proper frequency scaling and other
>> low-level controls.
>>
This is wrong, the downstream kernel may be doing "magic" to switch
clusters the other way around, and this is likely... Please, run your
benchmark on a upstream kernel: there may be differences.
>> Raw benchmark results can be found in the freqbench repository [3].
>> Below is a human-readable summary:
>>
>> Frequency domains: cpu1 cpu4
>> Offline CPUs: cpu1 cpu2 cpu3 cpu4 cpu5 cpu6 cpu7
>> Baseline power usage: 1130 mW
>>
>> ===== CPU 1 =====
>> Frequencies: 633 902 1113 1401 1536 1747 1843
>>
>> 633: 2058 3.2 C/MHz 48 mW 5.9 J 42.6 I/mJ 121.5 s
>> 902: 2930 3.2 C/MHz 72 mW 6.2 J 40.6 I/mJ 85.3 s
>> 1113: 3616 3.2 C/MHz 79 mW 5.4 J 46.0 I/mJ 69.1 s
>> 1401: 4551 3.2 C/MHz 125 mW 6.9 J 36.3 I/mJ 54.9 s
>> 1536: 4988 3.2 C/MHz 134 mW 6.7 J 37.1 I/mJ 50.1 s
>> 1747: 5674 3.2 C/MHz 179 mW 7.9 J 31.7 I/mJ 44.1 s
>> 1843: 5986 3.2 C/MHz 228 mW 9.5 J 26.3 I/mJ 41.8 s
>>
>> ===== CPU 4 =====
>> Frequencies: 1113 1401 1747 1958 2150 2208
>>
>> 1113: 5825 5.2 C/MHz 220 mW 9.4 J 26.5 I/mJ 42.9 s
>> 1401: 7324 5.2 C/MHz 317 mW 10.8 J 23.1 I/mJ 34.1 s
>> 1747: 9135 5.2 C/MHz 474 mW 13.0 J 19.2 I/mJ 27.4 s
>> 1958: 10247 5.2 C/MHz 578 mW 14.1 J 17.7 I/mJ 24.4 s
>> 2150: 11246 5.2 C/MHz 694 mW 15.4 J 16.2 I/mJ 22.2 s
>> 2208: 11551 5.2 C/MHz 736 mW 15.9 J 15.7 I/mJ 21.7 s
>>
>> [1] https://github.com/kdrag0n/freqbench
>> [2] https://www.eembc.org/coremark/
>> [3] https://github.com/kdrag0n/freqbench/tree/master/results/sdm660/main
>>
>> Signed-off-by: Danny Lin <danny@...ag0n.dev>
>> ---
>> arch/arm64/boot/dts/qcom/sdm660.dtsi | 16 ++++++++--------
>> 1 file changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/sdm660.dtsi b/arch/arm64/boot/dts/qcom/sdm660.dtsi
>> index 4abbdd03d1e7..ca985c5429db 100644
>> --- a/arch/arm64/boot/dts/qcom/sdm660.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/sdm660.dtsi
>> @@ -40,7 +40,7 @@ CPU0: cpu@100 {
>> compatible = "qcom,kryo260";
>> reg = <0x0 0x100>;
>> enable-method = "psci";
>> - capacity-dmips-mhz = <1024>;
>> + capacity-dmips-mhz = <636>;
>> next-level-cache = <&L2_1>;
>> L2_1: l2-cache {
>> compatible = "cache";
>> @@ -59,7 +59,7 @@ CPU1: cpu@101 {
>> compatible = "qcom,kryo260";
>> reg = <0x0 0x101>;
>> enable-method = "psci";
>> - capacity-dmips-mhz = <1024>;
>> + capacity-dmips-mhz = <636>;
>> next-level-cache = <&L2_1>;
>> L1_I_101: l1-icache {
>> compatible = "cache";
>> @@ -74,7 +74,7 @@ CPU2: cpu@102 {
>> compatible = "qcom,kryo260";
>> reg = <0x0 0x102>;
>> enable-method = "psci";
>> - capacity-dmips-mhz = <1024>;
>> + capacity-dmips-mhz = <636>;
>> next-level-cache = <&L2_1>;
>> L1_I_102: l1-icache {
>> compatible = "cache";
>> @@ -89,7 +89,7 @@ CPU3: cpu@103 {
>> compatible = "qcom,kryo260";
>> reg = <0x0 0x103>;
>> enable-method = "psci";
>> - capacity-dmips-mhz = <1024>;
>> + capacity-dmips-mhz = <636>;
>> next-level-cache = <&L2_1>;
>> L1_I_103: l1-icache {
>> compatible = "cache";
>> @@ -104,7 +104,7 @@ CPU4: cpu@0 {
>> compatible = "qcom,kryo260";
>> reg = <0x0 0x0>;
>> enable-method = "psci";
>> - capacity-dmips-mhz = <640>;
>> + capacity-dmips-mhz = <1024>;
>> next-level-cache = <&L2_0>;
>> L2_0: l2-cache {
>> compatible = "cache";
>> @@ -123,7 +123,7 @@ CPU5: cpu@1 {
>> compatible = "qcom,kryo260";
>> reg = <0x0 0x1>;
>> enable-method = "psci";
>> - capacity-dmips-mhz = <640>;
>> + capacity-dmips-mhz = <1024>;
>> next-level-cache = <&L2_0>;
>> L1_I_1: l1-icache {
>> compatible = "cache";
>> @@ -138,7 +138,7 @@ CPU6: cpu@2 {
>> compatible = "qcom,kryo260";
>> reg = <0x0 0x2>;
>> enable-method = "psci";
>> - capacity-dmips-mhz = <640>;
>> + capacity-dmips-mhz = <1024>;
>> next-level-cache = <&L2_0>;
>> L1_I_2: l1-icache {
>> compatible = "cache";
>> @@ -153,7 +153,7 @@ CPU7: cpu@3 {
>> compatible = "qcom,kryo260";
>> reg = <0x0 0x3>;
>> enable-method = "psci";
>> - capacity-dmips-mhz = <640>;
>> + capacity-dmips-mhz = <1024>;
>> next-level-cache = <&L2_0>;
>> L1_I_3: l1-icache {
>> compatible = "cache";
>> --
>> 2.29.2
>>
>
>
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