powerd on 8.0, is it considered safe?

[Alexander Motin]

Jeremy Chadwick wrote:
> I should note that on RELENG_7, EIST/SpeedStep didn't appear to work
> properly (cpufreq(4) driver reporting that the est piece wouldn't
> attach), which historically (for me) has resulted in ACPI throttling
> being done (which works).  Based on the sysctl output below, I believe
> acpi_perf is in use, but I'm not 100% certain.  The man page doesn't
> really disclose how to determine which driver is in use.
> 
> The X7SBA system in question is below.  Be aware I limit the lowest
> clock frequency to 1500MHz using debug.cpufreq.lowest="1500" in
> /boot/loader.conf, which is why you don't see anything lower in
> freq_levels.
> 
> dev.est.0.freq_settings: 3000/35000 2667/28000 2333/22000 2000/16000

This is the real set of EIST supported levels.

> dev.cpu.0.freq_levels: 3000/35000 2667/28000 2333/22000 2041/19250
2000/16000 1750/14000 1500/12000

All the rest of these are throttling.

I would recommend you to disable it by setting:
hint.p4tcc.0.disabled=1
hint.acpi_throttle.0.disabled=1

-- 
Alexander Motin