Re: kapm-idled shows 90+% cpu usage when idle

[Mikael Pettersson]

On Thu, 9 Aug 2001 19:33:42 -0400, safemode <[e-mail]> wrote:
>Is this a true usage reading or just some quirk that's supposed to happen?   
>I really doubt that this kernel daemon should really be using  cpu.  It seems 
>to respond with a higher cpu usage when i'm idle.  It immediately goes away 
>when something else uses cpu.   If you need any more info just ask.   I'm 

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