Re: Processor is almost never in C1 state

[Dino Klein <zagzag-lists-zY4eFNvK5D9If6P1QZMOBw@public.gmane.org>]

What's the problem? Do you actually experience slowness, or do you want 
your CPU to go into C1 just for the sake of going into C1?
Also, if you maxed out your cpu with that program, then that means that 
the processor was too busy to go into any of the sleep modes; therefore, 
all the counters should have remained unchanged.
If you want to keep your CPU from going into C1/C2, then open a terminal 
and run: nice bash -c 'while true; do false; done'
that will guarantee that the cpu will never go into sleep mode, while 
yielding to programs with higher priority.


dogshu wrote:

> Hello,
> 
> I have a Toshiba Portege laptop with a 500 mhz pentium-3 mobile CPU. 
> The processor is almost never is in the C1 state, and spends 99.9% of
> the time in the C2 state, even when doing heavy processing.
> 
> After a night of compiling KDE, and while running the "burnP6" program
> included in the "cpuburn 1.4" package, this is the output of
> /proc/acpi/processor/CPU0/power:
> 
> active state:            C2
> default state:           C1
> bus master activity:     00000000
> states:
>     C1:                  promotion[C2] demotion[--] latency[000] usage[00009710]
>    *C2:                  promotion[--] demotion[C1] latency[001] usage[12232108]
>     C3:                  <not supported>
> 
> As you can see, even though the processor is being maxed out by
> burnP6, it remains in the C2 state and doesn't really use the C1 state
> at all.
> 
> I don't mind having the CPU in this lower power/lower performance
> state most of the time... however I occassionally like to play DVDs on
> this laptop, and I need all the CPU power I can get when playing DVDs,
> or else  I will get lots of dropped frames.
> 
> I am running kernel 2.6.10-rc2-mm4.  I noticed that in the kernel
> parameters I can disable the C2 state altogether, but I'd rather not
> have to reboot whenever I play a DVD.  Is there a way to tweak ACPI so
> that the processor spends more time in the C1 state, without giving up
> the C2 state entirely?
> 
> thanks for any help,
> Jim Faulkner
> 
> 
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