kapm-idled ???

kapm-idled ???

Post by Ken Schroc » Mon, 28 Jan 2002 02:47:35



I am using Mandrake 8.1 on a Duron

Occasionally this process sucks 50% to 60% cpu for several minutes
Anybody know why? (I don't have apmd running)

 
 
 

kapm-idled ???

Post by Dances With Cro » Mon, 28 Jan 2002 03:21:22


On Sat, 26 Jan 2002 17:47:35 GMT, Ken Schrock staggered into the Black
Sun and said:

Quote:> I am using Mandrake 8.1 on a Duron
> Occasionally this process sucks 50% to 60% cpu for several minutes
> Anybody know why? (I don't have apmd running)

If you had bothered to search
http://groups.google.com/advanced_group_search for keyword "kapm-idle"
and newsgroups comp.os.linux.* , you would've had an answer very
quickly.

kapm-idled is a kernel process whose purpose in life is to run when
nothing else is running, and issue HLT instructions to an x86 processor.
(A processor executing a HLT instruction uses much less energy than a
processor executing any other instruction.)  Many people have noticed
this, and some of them freaked out.  Because this is counterproductive,
recent versions of the kernel (2.4.16, certainly) do not report
kapm-idled as using any CPU at all.

--
Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
Brainbench MVP for Linux Admin /
http://www.brainbench.com     /  "He is a rhythmic movement of the
-----------------------------/    penguins, is Tux." --MegaHAL

 
 
 

kapm-idled ???

Post by Ken Schroc » Mon, 28 Jan 2002 09:49:08



> On Sat, 26 Jan 2002 17:47:35 GMT, Ken Schrock staggered into the Black
> Sun and said:
> > I am using Mandrake 8.1 on a Duron
> > Occasionally this process sucks 50% to 60% cpu for several minutes
> > Anybody know why? (I don't have apmd running)

> If you had bothered to search
> http://groups.google.com/advanced_group_search for keyword "kapm-idle"
> and newsgroups comp.os.linux.* , you would've had an answer very
> quickly.

It seems that I got an answer very quickly this way
And got to allow someone with an ego problem to act superior too
This way seems like way more fun all the way around

Replies like this do more damage to Linux and than all other factors
combined
Now I am sure someone as superior as you must knows this, so
IS it that you just don't care, or is Bill paying you?

Quote:> kapm-idled is a kernel process whose purpose in life is to run when
> nothing else is running, and issue HLT instructions to an x86 processor.
> (A processor executing a HLT instruction uses much less energy than a
> processor executing any other instruction.)  Many people have noticed
> this, and some of them freaked out.  Because this is counterproductive,
> recent versions of the kernel (2.4.16, certainly) do not report
> kapm-idled as using any CPU at all.

> --
> Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
> Brainbench MVP for Linux Admin /
> http://www.brainbench.com     /  "He is a rhythmic movement of the
> -----------------------------/    penguins, is Tux." --MegaHAL

 
 
 

kapm-idled ???

Post by Peter T. Breue » Mon, 28 Jan 2002 10:02:02




>> On Sat, 26 Jan 2002 17:47:35 GMT, Ken Schrock staggered into the Black
>> Sun and said:
>> > I am using Mandrake 8.1 on a Duron
>> > Occasionally this process sucks 50% to 60% cpu for several minutes
>> > Anybody know why? (I don't have apmd running)

>> If you had bothered to search
>> http://groups.google.com/advanced_group_search for keyword "kapm-idle"
>> and newsgroups comp.os.linux.* , you would've had an answer very
>> quickly.
> It seems that I got an answer very quickly this way
> And got to allow someone with an ego problem to act superior too
> This way seems like way more fun all the way around

Next time, I think you should just be left to search for yourself.
You'll then learn how to search, as well as learning the answer.
This way, you just learn how to make a nuisance of yourself at the
expense of other people.

Quote:> Replies like this do more damage to Linux and than all other factors

Put that ego back in a bag, and pronounce "thank you", correctly..

Quote:> combined
> Now I am sure someone as superior as you must knows this, so
> IS it that you just don't care, or is Bill paying you?
>> kapm-idled is a kernel process whose purpose in life is to run when
>> nothing else is running, and issue HLT instructions to an x86 processor.
>> (A processor executing a HLT instruction uses much less energy than a
>> processor executing any other instruction.)  Many people have noticed
>> this, and some of them freaked out.  Because this is counterproductive,
>> recent versions of the kernel (2.4.16, certainly) do not report
>> kapm-idled as using any CPU at all.

2.4.17, which I am using, does show kapm-idled at 50% when I am on
battery power (toshiba portege 4000).  When it shows it, the fan also
goes, so I am a little worried about that.  Might be the famous broken
apm bios call syndrome.  OTOH, it is down at 0% usually, and the fan is
usually off.

I didn't realize that accounting had changed. Thanks (to DWC).

Peter

 
 
 

1. kapm-idled shows 90+% cpu usage when idle

Do you have CONFIG_APM_CPU_IDLE=y in your .config? If so, disable it.

There was a thread about this problem some months ago. I found
that on all of my APM-capable machines, including a Dell laptop,
CONFIG_APM_CPU_IDLE=y had a negative effect. The kernel ended up
in a tight loop performing tons of APM IDLE BIOS calls, since each
BIOS call returned immediately without having idled the CPU.

Leaving CONFIG_APM_CPU_IDLE unset lets the kernel use its own
"HLT when idle" code. On my main development box, idle CPU
temperature dropped >10 degrees C, and kapm-idled now uses 0% CPU.

/Mikael
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