acpi_thorttle and cpufreq/ichss questions

Srikanth, Throvagunta sthrovag at gmail.com
Mon Oct 17 00:23:19 PDT 2005


Harry,
ACPI throttling is closely system-dependent. FreeBSD does its best at
arriving at the right values. I recommend you should look into sources
for complete answers. By the way, you have forgot to mention the
version [like 6.0] of FreeBSD you are actually running on your laptop.
That will be useful information to give for an answer.
--Srikanth

--
Date:       Wed, 28 Sep 2005 14:49:32 +0200
From:       Emanuel Strobl <Emanuel.strobl at gmx.net>
To:           freebsd-questions at freebsd.org
Subject:   acpi_thorttle and cpufreq/ichss questions

Hello,

my laptop (PIII LV) runs fine with cpufreq and ichss:

dev.ichss.0.%desc: SpeedStep ICH
dev.ichss.0.%driver: ichss
dev.ichss.0.%parent: cpu0
dev.ichss.0.freq_settings: 794/-1 497/-1


If I understand the output correctly i have two SpeedSteps, the full 800MHz==20
(with higher voltage) and 500MHz.

But now I also have acpi_throttle (if I don't disable it=20
in /boot/loader.conf):

dev.acpi_throttle.0.%desc: ACPI CPU Throttling
dev.acpi_throttle.0.%driver: acpi_throttle
dev.acpi_throttle.0.%parent: cpu0
dev.acpi_throttle.0.freq_settings: 10000/-1 8750/-1 7500/-1 6250/-1 5000/-1==20
3750/-1 2500/-1 1250/-1

What do these values tell me? I think that are divisors, but how can I see==20
which one is used? I remember that some time back I saw at boot time some=20
information about "throttle has xx steps, currently using 100%" or=20
something like that.
Can I constrain the divisors, lets say I want to have only 10000, 7500 and==20
5000? (I know I can limit the lowest frequency cpufreq may use with=20
"debug.cpufreq.lowest=3D310" but then I don't know if it throttles the=20
800MHz mode (thus using high core voltage) or if it throttles the power=20
saving 500MHz mode)

And what does this tell me:

hw.acpi.cpu.cx_supported: C1/0 C2/10 C3/85
hw.acpi.cpu.cx_lowest: C1
hw.acpi.cpu.cx_usage: 100.00% 0.00% 0.00%

Thanks in advance,

=2DHarry


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