Is the C3 possible with SMP?

Alexander Motin mav at FreeBSD.org
Sun Nov 2 14:43:41 PST 2008


Alexandre "Sunny" Kovalenko wrote:
> You would not happen to have USB loaded or built into kernel? If you do,

At home I have external USB keyboard and mouse, so yes, it is built in. 
It would be difficult to unload and reload it each time I connect something.

I have read in ICH8M datasheet about special feature of reducing USB 
busmaster activity on idle periods to support C3 state. Do you know 
something about it?

> you will practically never go into C3. What does
> 
> sysctl dev.cpu | grep cx_usage 
> 
> say?

%sysctl -a | grep cx_
hw.acpi.cpu.cx_lowest: C2
dev.cpu.0.cx_supported: C1/1 C2/1 C3/57
dev.cpu.0.cx_lowest: C2
dev.cpu.0.cx_usage: 0.00% 100.00% 0.00%
dev.cpu.1.cx_supported: C1/1 C2/1 C3/57
dev.cpu.1.cx_lowest: C3
dev.cpu.1.cx_usage: 0.00% 0.43% 99.56%

-- 
Alexander Motin


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