Re: CPU C-state storange on Panasonic TOUGH BOOK CF-R9

on 12/09/2010 13:37 Alexander Motin said the following:
> Andriy Gapon wrote:
>> acpi_lid0: Lid closed
>> em0: Link is up 1000 Mbps Full Duplex
>> PROCESSOR-0722 [402244] cpu_cx_cst            : acpi_cpu0: Got C2 - 245 latency
>> PROCESSOR-0722 [403097] cpu_cx_cst            : acpi_cpu1: Got C2 - 245 latency
>> PROCESSOR-0722 [403855] cpu_cx_cst            : acpi_cpu2: Got C2 - 245 latency
>> PROCESSOR-0722 [405022] cpu_cx_cst            : acpi_cpu3: Got C2 - 245 latency
>>
>> Maybe because of this?
>> It seems like you do something and ACPI disables C3, leaving only C2/
> 
> One strange thing. During boot it can be seen:
> acpi_cpu0: Got C2 - 205 latency
> acpi_cpu0: Got C3 - 245 latency
> , but after boot in sysctl we can see:
> dev.cpu.0.cx_supported: C1/3 C2/245
> 
> It respecting latency it looks like not C3 got lost, but C2. AFAIR,
> sysctl numbers C-states completely abstract, just as array indexes. So
> thing reported as C2 could instead be C3, while C2 is absent for some
> reason.

Observations are correct, but incomplete; the conclusions are wrong.
At the end of the boot there are message like this one:
PROCESSOR-0722 [402244] cpu_cx_cst            : acpi_cpu0: Got C2 - 245 latency
This is a result of re-evaluation of _CST because of a notification from ACPI.

-- 
Andriy Gapon