Hikey Power Model - eas-dev

14 Oct 2015


      Hi all,
Below are raw power data on Hikey board; with this power data i'd like to
create the power model for Hikey.
- Measure method:
On Hikey board, we cannot measure buck1 which is dedicated for AP
subsystem; so turned to measure VDD_4V2 to remove R247 and remount
shunt resistor 470mOhm. At a result, the power data includes many
other LDO's power data.
+--------------+       +-------------+
          4.2v          |              | Buck1 |             |
---- Shunt Resistor --->| PMIC: Hi6553 |------>| SoC: Hi6220 |
 ^                  ^   |              |       |   ACPU      |
 |                  |   +--------------+       +-------------+
 |-> Energy Probe <-|
- Measured raw data:
sys_suspend: AP system suspend state
  cluster_off: two clusters are powered off
  cluster_on:  1 cluster is powered on, all cpus are powered off
  cpu_wfi:     1 cluster is powered on, last cpu enters 'wfi' but other cpus
               are powered off
  voltage:     voltage for every OPP
# OPP sys_suspend cluster_off cluster_on cpu_wfi cpu_on voltage
    208  328  347  366  374  435  1.04
    432  328  344  374  388  499  1.04
    729  331  351  400  409  606  1.09
    960  329  353  430  443  750  1.18
   1200  331  365  486  506  988  1.33
Hikey Power Model
Power [mW]
  500 ++--------+-------------+---------+---------++ cluster_off **A***
      +         +             +         +          D  cluster_on ##B###
  450 ++.........................................%%+     cpu_wfi $$C$$$
  400 ++.......................................%%.++ cpu p-state %%D%%%
      |         :             :         :    %%    |
  350 ++...................................%%.....++
      |         :             :         :%%        |
  300 ++...............................%D.........++
  250 ++...........................%%%%...........++
      |         :             : %%%     :          |
  200 ++....................%%D%..................++
      |         :      %%%%%  :         :          |
  150 ++...........%%%%...........................++
      |       %%D%%           :         :     #####B
  100 ++.%%%%%.....................#####B#####....++
   50 D%%..............#######B####...............++
      A*********A*************A*********A**********A
    0 C$$$$$$$$$C$$$$$$$$$$$$$C$$$$$$$$$C$$$$$----++
     208       432           729       960       1200
                     Frequency [MHz]
Hikey Power Efficiency
Power Efficiency [mW/MHz]                Voltage [v]
  0.45 ++-------+----------+--------+-------++ 3         Cluster Power **A***
       +        +          +        +        +        CPU Static Power ##B###
   0.4 ++...................................$C       CPU Dynamic power $$C$$$
       |        :          :        :    $$$++ 2.5             Voltage %%D%%%
  0.35 ++.............................$$$...++
       |        :          :      $$C$       |
   0.3 C$$$$$$$$..............$$$$..........++ 2
       |        C$$$$$$$$$$C$$      :        |
  0.25 ++...................................++ 1.5
   0.2 ++................................%%%%D
       |        :          :    %%%%D%%%%    |
  0.15 D%%%%%%%%D%%%%%%%%%%D%%%%............++ 1
       |        :          :        :        |
   0.1 A********.........................****A
       |        A**********A********A****   ++ 0.5
  0.05 ++...................................++
       B########B##########+    ####B########B
     0 ++-------+----------B####----+-------++ 0
      208      432        729      960     1200
                   Frequency [MHz]
- Power Model On Hikey:
According to before we have discussed for power model, i think below is the
prefered power data for Hikey which calculated from raw power date:
static struct idle_state idle_states_cluster_a53[] = {
    { .power = 0 },
    { .power = 0 },
};
/*
 * Use (cluster_on - cluster_off) for every OPP
 */
static struct capacity_state cap_states_cluster_a53[] = {
        /* Power per cluster */
    { .cap = 178,  .power =  19, },
    { .cap = 369,  .power =  30, },
    { .cap = 622,  .power =  49, },
    { .cap = 819,  .power =  77, },
    { .cap = 1024, .power = 121, },
};
/*
 * Use (cpu_wfi - cluster_on) for every OPP, then calculate the
 * average value for wfi's power data; But we can see actually
 * the idle state of "WFI" will be impacted by voltage.
 */
static struct idle_state idle_states_core_a53[] = {
    { .power = 12 },
    { .power =  0 },
};
/*
 * Use (cpu_on - cluster_off) for every OPP
 */
static struct capacity_state cap_states_core_a53[] = {
        /* Power per cpu */
    { .cap = 178,  .power =  69, },  /* 208MHz */
    { .cap = 369,  .power = 125, },  /* 432MHz */
    { .cap = 622,  .power = 206, },  /* 729MHz */
    { .cap = 819,  .power = 320, },  /* 960MHz */
    { .cap = 1024, .power = 502, },  /* 1.2GHz */
};
If have any questions or issues for upper energy model data, please let me know;
Appreciate review and comments in advance.
- Some other questions
Q1: Jian & Dan, voltage for 1.2GHz is quite high, could you help check
  the voltage table for OPPs, if there have any unexpected value?
Q2: Morten, if i want to do more profiling on EAS, do you suggest i should
  refer which branch now? I think now EASv5 patches are relative old,
  so want to check if we have better candidate or not.
i downloaded the git repo: git://www.linux-arm.org/linux-power.git, branch
  energy_model_rfc_v5.1; but there have no sched-dvfs related patches.
Thanks,
Leo Yan