2008-10-02 08:53:44

by Thomas Gleixner

Subject: Re: APIC frequency too slow on HP dv5z

On Tue, 30 Sep 2008, Howard Chu wrote:

> More often than not, on a warm boot I see something like this
>
> msg.new:[ 1.940031] Using local APIC timer interrupts.
> msg.new:[ 1.944031] APIC timer calibration result 466046
> msg.new:[ 1.944031] Detected 0.466 MHz APIC timer.
> msg.new:[ 1.944031] APIC frequency too slow, disabling apic timer
>
> On cold boots it may see 12.5MHz, or may not...
>
> [ 2.000584] Using local APIC timer interrupts.
> [ 2.004067] APIC timer calibration result 12500236
> [ 2.004080] Detected 12.500 MHz APIC timer.
>
> I haven't figured out yet what the pattern is behind the behavior. Has anyone
> else seen this kind of problem before?

Hmm, strange. Which kernel version ?

Thanks,

tglx

2008-10-02 09:06:00

by Howard Chu

Subject: Re: APIC frequency too slow on HP dv5z

Thomas Gleixner wrote:
> On Tue, 30 Sep 2008, Howard Chu wrote:
>
>> More often than not, on a warm boot I see something like this
>>
>> msg.new:[ 1.940031] Using local APIC timer interrupts.
>> msg.new:[ 1.944031] APIC timer calibration result 466046
>> msg.new:[ 1.944031] Detected 0.466 MHz APIC timer.
>> msg.new:[ 1.944031] APIC frequency too slow, disabling apic timer
>>
>> On cold boots it may see 12.5MHz, or may not...
>>
>> [ 2.000584] Using local APIC timer interrupts.
>> [ 2.004067] APIC timer calibration result 12500236
>> [ 2.004080] Detected 12.500 MHz APIC timer.
>>
>> I haven't figured out yet what the pattern is behind the behavior. Has anyone
>> else seen this kind of problem before?
>
> Hmm, strange. Which kernel version ?

I only started paying attention recently. 2.6.27-rc4 thru rc7 for sure. I'm
running rc7 right now, that's what those log snippets are from.

--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/

2008-10-02 09:13:47

by Thomas Gleixner

Subject: Re: APIC frequency too slow on HP dv5z

On Thu, 2 Oct 2008, Howard Chu wrote:
> Thomas Gleixner wrote:
> > On Tue, 30 Sep 2008, Howard Chu wrote:
> >
> > > More often than not, on a warm boot I see something like this
> > >
> > > msg.new:[ 1.940031] Using local APIC timer interrupts.
> > > msg.new:[ 1.944031] APIC timer calibration result 466046
> > > msg.new:[ 1.944031] Detected 0.466 MHz APIC timer.
> > > msg.new:[ 1.944031] APIC frequency too slow, disabling apic timer
> > >
> > > On cold boots it may see 12.5MHz, or may not...
> > >
> > > [ 2.000584] Using local APIC timer interrupts.
> > > [ 2.004067] APIC timer calibration result 12500236
> > > [ 2.004080] Detected 12.500 MHz APIC timer.
> > >
> > > I haven't figured out yet what the pattern is behind the behavior. Has
> > > anyone
> > > else seen this kind of problem before?
> >
> > Hmm, strange. Which kernel version ?
>
> I only started paying attention recently. 2.6.27-rc4 thru rc7 for sure. I'm
> running rc7 right now, that's what those log snippets are from.

Ok. Can you please add apic=verbose to the kernel command line so we
get more detailed info about that ?

Thanks,

tglx

2008-10-02 22:56:40

by Howard Chu

Subject: Re: APIC frequency too slow on HP dv5z

Thomas Gleixner wrote:
> On Thu, 2 Oct 2008, Howard Chu wrote:
>> Thomas Gleixner wrote:
>>> On Tue, 30 Sep 2008, Howard Chu wrote:
>>>
>>>> More often than not, on a warm boot I see something like this
>>>>
>>>> msg.new:[ 1.940031] Using local APIC timer interrupts.
>>>> msg.new:[ 1.944031] APIC timer calibration result 466046
>>>> msg.new:[ 1.944031] Detected 0.466 MHz APIC timer.
>>>> msg.new:[ 1.944031] APIC frequency too slow, disabling apic timer
>>>>
>>>> On cold boots it may see 12.5MHz, or may not...
>>>>
>>>> [ 2.000584] Using local APIC timer interrupts.
>>>> [ 2.004067] APIC timer calibration result 12500236
>>>> [ 2.004080] Detected 12.500 MHz APIC timer.
>>>>
>>>> I haven't figured out yet what the pattern is behind the behavior. Has
>>>> anyone
>>>> else seen this kind of problem before?
>>> Hmm, strange. Which kernel version ?
>> I only started paying attention recently. 2.6.27-rc4 thru rc7 for sure. I'm
>> running rc7 right now, that's what those log snippets are from.
>
> Ok. Can you please add apic=verbose to the kernel command line so we
> get more detailed info about that ?

OK. Of course since you asked for it, the problem refused to show up. It took
about a dozen reboots before it appeared again. And then it took 3-4 reboots
to make it go away. Full dmesg output is here:
http://www.highlandsun.com/hyc/msg.rc7.bad.gz
http://www.highlandsun.com/hyc/msg.rc7.ok.gz

--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/