Processor is almost never in C1 state

Processor is almost never in C1 state

[dogshu]

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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Re: Processor is almost never in C1 state

[Vlad Yasevich]

I have somewhat similar numbers (C1 is has a larger
value, but is almost never used) on a Compaq Evo N620c.

I found, just by playing around, that by removing
USB modules, I can make my system go into C1 much
faster when doing CPU intensive operations.

See if that works for you.

-vlad

On Mon, 2004-12-06 at 11:10 -0500, 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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Re: Processor is almost never in C1 state

[Ow Mun Heng]

On Wed, 2004-12-08 at 04:04, Vlad Yasevich wrote:
> I have somewhat similar numbers (C1 is has a larger
> value, but is almost never used) on a Compaq Evo N620c.cat power 
active state:            C3
default state:           C1
bus master activity:     20040400
states:
    C1:  promotion[C2] demotion[--] latency[000] usage[01802320]
    C2:  promotion[C3] demotion[C1] latency[050] usage[03740741]
   *C3:  promotion[--] demotion[C2] latency[050] usage[03718525]


> 
> I found, just by playing around, that by removing
> USB modules, I can make my system go into C1 much
> faster when doing CPU intensive operations.

USB is usually the problem. 

> See if that works for you.
> 
> -vlad
> 
> On Mon, 2004-12-06 at 11:10 -0500, 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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--
Ow Mun Heng
Gentoo/Linux on D600 1.4Ghz 
Neuromancer 11:33:26 up 2:35, 7 users, 0.32, 0.37, 0.68 




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Re: Processor is almost never in C1 state

[Stefan Seyfried]

On Mon, Dec 06, 2004 at 11:10:31AM -0500, dogshu wrote:

> 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.
 
>     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.

The latency of C2 is very low, so there is no reason to use C1 very
often or for a prolonged amount of time.  If the Processor is doing
"real work" it is in no C-state at all (you might think of it as "C0" :-)
if i understand things correctly (please someone more knowledgeable
correct me if i am wrong).
-- 
Stefan Seyfried



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Re: Processor is almost never in C1 state

[Dino Klein]

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
> 
> 
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now. 
> http://productguide.itmanagersjournal.com/
> _______________________________________________
> Acpi-devel mailing list
> Acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
> https://lists.sourceforge.net/lists/listinfo/acpi-devel



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Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
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