arm: dts: vexpress-v2p-ca15_a7: Add dynamic-power-coefficient properties

The values are computed by measuring energy over a 10 secs sysbench
workload running at each frequency and affine to 1 or 2 A15's as well as
1, 2 or 3 A7's. The Power values for individual cpus are calculated from
the Energy values divided by workload runtime by taking the difference
of the energy values between n+1 and n cpus.

P [mW] = C * freq [Mhz] * voltage [mV] * voltage [mV] / 1000000000

C = P [mW] / freq [Mhz] * voltage [mV] * voltage [mV] * 1000000000

The actual C (dynamic-power-coefficient) value is the mean value out of
all the C values of the OPP's.

A15:
     freq       power  voltage  dyn_pwr_coef
     [MhZ]      [mW]      [mV]
0   500.0   534.57550      900   1319.939506
1   600.0   547.15468      900   1125.832675
2   700.0   572.22060      900   1009.207407
3   800.0   607.76592      900    937.910370
4   900.0   648.50552      900    889.582332
5  1000.0   693.86776      900    856.626864
6  1100.0   916.51314      975    876.469442
7  1200.0  1198.57566     1050    905.952880

                            mean: 990

A7:

     freq      power  voltage  dyn_pwr_coef
     [MhZ]      [mW]     [mV]
0   350.0   40.17430      900    141.708289
1   400.0   42.68700      900    131.750000
2   500.0   54.25716      900    133.968296
3   600.0   64.09914      900    131.891235
4   700.0   74.09736      900    130.683175
5   800.0   82.69694      900    127.618735
6   900.0  113.71386      975    132.911225
7  1000.0  144.94124     1050    131.465977

                           mean: 133

The ratio between A15 and A7 is 990/113 = 7.44

This value (7.44) is very close to mean ratio between the power value of
A15 an A7 of the per sched-domain Energy Model (7.96):

  mV  Mhz  MhZ old EM      ratio
       A7  A15 core power
 900  350  500 6997/1024   6.83
 900  400  600 5177/761    6.80
 900  500  700 3846/549    7.01
 900  600  800 3524/447    7.88
 900  700  900 3125/407    7.68
 900  800 1000 2756/334    8.25
 975  900 1100 2312/275    8.40
1050 1000 1200 2021/187   10.80

                    mean:  7.96

Change-Id: I93ef375d05ff769481a07f2c74f061e307cb14d4
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>

diff --git a/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts b/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts
index ac6b90e9d806042f153d6cc4260b1dba765904f2..75663ed4817fc88bc71e842e26b8f7ebf690a75b 100644 (file)
--- a/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts
+++ b/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts
@@ -42,6 +42,7 @@
                        cci-control-port = <&cci_control1>;
                        cpu-idle-states = <&CLUSTER_SLEEP_BIG>;
                        capacity-dmips-mhz = <1024>;
+                       dynamic-power-coefficient = <990>;
                };
 
                cpu1: cpu@1 {
@@ -51,6 +52,7 @@
                        cci-control-port = <&cci_control1>;
                        cpu-idle-states = <&CLUSTER_SLEEP_BIG>;
                        capacity-dmips-mhz = <1024>;
+                       dynamic-power-coefficient = <990>;
                };
 
                cpu2: cpu@2 {
@@ -60,6 +62,7 @@
                        cci-control-port = <&cci_control2>;
                        cpu-idle-states = <&CLUSTER_SLEEP_LITTLE>;
                        capacity-dmips-mhz = <516>;
+                       dynamic-power-coefficient = <133>;
                };
 
                cpu3: cpu@3 {
@@ -69,6 +72,7 @@
                        cci-control-port = <&cci_control2>;
                        cpu-idle-states = <&CLUSTER_SLEEP_LITTLE>;
                        capacity-dmips-mhz = <516>;
+                       dynamic-power-coefficient = <133>;
                };
 
                cpu4: cpu@4 {
@@ -78,6 +82,7 @@
                        cci-control-port = <&cci_control2>;
                        cpu-idle-states = <&CLUSTER_SLEEP_LITTLE>;
                        capacity-dmips-mhz = <516>;
+                       dynamic-power-coefficient = <133>;
                };
 
                idle-states {