Patch "arm64: dts: qcom: sdm845: correct dynamic power coefficients" has been added to the 6.3-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    arm64: dts: qcom: sdm845: correct dynamic power coefficients

to the 6.3-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm64-dts-qcom-sdm845-correct-dynamic-power-coeffici.patch
and it can be found in the queue-6.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 10168c0ab408a1b624222ae734c8e213c0a65ca8
Author: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Date:   Fri Jan 6 17:46:18 2023 +0100

    arm64: dts: qcom: sdm845: correct dynamic power coefficients
    
    [ Upstream commit 44750f153699b6e4f851a399287e5c8df208d696 ]
    
    While stressing EAS on my dragonboard RB3, I have noticed that LITTLE cores
    where never selected as the most energy efficient CPU whatever the
    utilization level of waking task.
    
    energy model framework uses its cost field to estimate the energy with
    the formula:
    
      nrg = cost of the selected OPP * utilization / CPU's max capacity
    
    which ends up selecting the CPU with lowest cost / max capacity ration
    as long as the utilization fits in the OPP's capacity.
    
    If we compare the cost of a little OPP with similar capacity of a big OPP
    like :
           OPP(kHz)   OPP capacity    cost     max capacity   cost/max capacity
    LITTLE 1766400    407             351114   407            863
    big    1056000    408             520267   1024           508
    
    This can be interpreted as the LITTLE core consumes 70% more than big core
    for the same compute capacity.
    
    According to [1], LITTLE consumes 10% less than big core for Coremark
    benchmark at those OPPs. If we consider that everything else stays
    unchanged, the dynamic-power-coefficient of LITTLE core should be
    only 53% of the current value: 290 * 53% = 154
    
    Set the dynamic-power-coefficient of CPU0-3 to 154 to fix the energy model.
    
    [1] https://github.com/kdrag0n/freqbench/tree/master/results/sdm845/main
    
    Fixes: 0e0a8e35d725 ("arm64: dts: qcom: sdm845: correct dynamic power coefficients")
    Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
    Signed-off-by: Bjorn Andersson <andersson@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230106164618.1845281-1-vincent.guittot@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
index 479859bd8ab33..ac9d327179a65 100644
--- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
@@ -94,7 +94,7 @@ CPU0: cpu@0 {
 			reg = <0x0 0x0>;
 			enable-method = "psci";
 			capacity-dmips-mhz = <611>;
-			dynamic-power-coefficient = <290>;
+			dynamic-power-coefficient = <154>;
 			qcom,freq-domain = <&cpufreq_hw 0>;
 			operating-points-v2 = <&cpu0_opp_table>;
 			interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_EBI1 3>,
@@ -120,7 +120,7 @@ CPU1: cpu@100 {
 			reg = <0x0 0x100>;
 			enable-method = "psci";
 			capacity-dmips-mhz = <611>;
-			dynamic-power-coefficient = <290>;
+			dynamic-power-coefficient = <154>;
 			qcom,freq-domain = <&cpufreq_hw 0>;
 			operating-points-v2 = <&cpu0_opp_table>;
 			interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_EBI1 3>,
@@ -142,7 +142,7 @@ CPU2: cpu@200 {
 			reg = <0x0 0x200>;
 			enable-method = "psci";
 			capacity-dmips-mhz = <611>;
-			dynamic-power-coefficient = <290>;
+			dynamic-power-coefficient = <154>;
 			qcom,freq-domain = <&cpufreq_hw 0>;
 			operating-points-v2 = <&cpu0_opp_table>;
 			interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_EBI1 3>,
@@ -164,7 +164,7 @@ CPU3: cpu@300 {
 			reg = <0x0 0x300>;
 			enable-method = "psci";
 			capacity-dmips-mhz = <611>;
-			dynamic-power-coefficient = <290>;
+			dynamic-power-coefficient = <154>;
 			qcom,freq-domain = <&cpufreq_hw 0>;
 			operating-points-v2 = <&cpu0_opp_table>;
 			interconnects = <&gladiator_noc MASTER_APPSS_PROC 3 &mem_noc SLAVE_EBI1 3>,



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux