Re: NO_HZ: timer interrupt stuck [Re: Linux 2.6.21-rc1]
From: Arjan van de Ven
Date: Thu Feb 22 2007 - 11:42:30 EST
On Thu, 2007-02-22 at 17:27 +0100, Pierre Ossman wrote:
> Thomas Gleixner wrote:
> > Here is the reason. The local APIC stops working in C3 state and we fall
> > back to the PIT in that case. Not really exciting for dynticks, but the
> > only way to keep the system alive. There is a patch coming up from
> > Intel, which finds out how to use HPET even if it is not enabled by the
> > BIOS. This will still end up on IRQ#0, but will give way longer idle
> > sleeps than the PIT.
> So then the next two questions are; is it possible to disable C3
yeah there is a commandline thingy for it
> and is
> it a net power gain to get rid of the wakeups in favor of having C3.
no; c3 saves a TON more power.
you can try enabling HPET in your BIOS...
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org
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