Skylake Power Management on 10.3

[mnd999]

Hi,

I've been trying to figure out whether or not powerd is actually doing anything on my Skylake desktop, and I'm starting to think maybe it isn't.

I did:

sysctl debug.cpufreq.verbose=0

And the result was a system log full of

cpufreq: get returning known freq 4001

To be honest I'm not sure if all this logging is causing it to throttle up to 100% cpu, or if the CPU is just deciding to spend all its time in its turbo boost state (which i think is what 4001 means).

Can anyone shed any light on whether this is normal? Is there a better way to track P states?

 

[wblock@]

service powerd onestop

Then powerd -v, adding the same options that you use in /etc/rc.conf. It will print the current state to the terminal.

 

[mnd999]

Thanks, yes that's a much better way of doing it.

The short of it is with the default settings, it doesn't work:

powerd: unable to determine AC line status
load  17%, current freq 4001 MHz ( 0), wanted freq 3875 MHz
changing clock speed from 4001 MHz to 4000 MHz
load  3%, current freq 4000 MHz ( 1), wanted freq 3753 MHz
changing clock speed from 4000 MHz to 3800 MHz
load  88%, current freq 3800 MHz ( 2), wanted freq 8002 MHz
changing clock speed from 3800 MHz to 4001 MHz
load  11%, current freq 4001 MHz ( 0), wanted freq 7751 MHz
load  6%, current freq 4001 MHz ( 0), wanted freq 7508 MHz
load  0%, current freq 4001 MHz ( 0), wanted freq 7273 MHz
load  10%, current freq 4001 MHz ( 0), wanted freq 7045 MHz
load  0%, current freq 4001 MHz ( 0), wanted freq 6824 MHz
load  87%, current freq 4001 MHz ( 0), wanted freq 8002 MHz
load  0%, current freq 4001 MHz ( 0), wanted freq 7751 MHz
load  0%, current freq 4001 MHz ( 0), wanted freq 7508 MHz
load  6%, current freq 4001 MHz ( 0), wanted freq 7273 MHz
load  6%, current freq 4001 MHz ( 0), wanted freq 7045 MHz
load  0%, current freq 4001 MHz ( 0), wanted freq 6824 MHz
load  0%, current freq 4001 MHz ( 0), wanted freq 6610 MHz
load  7%, current freq 4001 MHz ( 0), wanted freq 6403 MHz
load  53%, current freq 4001 MHz ( 0), wanted freq 8002 MHz
load  25%, current freq 4001 MHz ( 0), wanted freq 8002 MHz
load  0%, current freq 4001 MHz ( 0), wanted freq 7751 MHz
load  3%, current freq 4001 MHz ( 0), wanted freq 7508 MHz
load  4%, current freq 4001 MHz ( 0), wanted freq 7273 MHz
load  3%, current freq 4001 MHz ( 0), wanted freq 7045 MHz

Something (probably X) is blipping the CPU to keep it jammed at max. I changed the default interval to 1 second with better results. I'll see how this affects responsiveness.

 

[wblock@]

A Haswell system here seems to do okay with these settings. Even in X, it drops to 754MHz when idle.
/boot/loader.conf

aesni_load="YES"
coretemp_load="YES"
drm.i915.enable_rc6=7
hwpmc_load="YES"
hint.p4tcc.0.disabled="1"
hint.acpi_throttle.0.disabled="1"
hw.acpi.cpu.cx_lowest="cmax"

/etc/rc.conf

powerd_enable="YES"
powerd_flags="-a hadp -n hadp -p50"