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Date: Fri, 24 Dec 2010 17:16:40 +0100
From: Stefan Farfeleder <stefanf@FreeBSD.org>
To: Alexander Motin <mav@FreeBSD.org>
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Cc: freebsd-current@freebsd.org
Subject: Re: eventtimers hiccups
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On Fri, Dec 24, 2010 at 04:49:50PM +0200, Alexander Motin wrote:
> 
> Have you tried to look on what happens with your HPET interrupts during
> the problem? Is it timer hardware/driver problem, or something else?
> 
> Have you tried to use LAPIC timer? - it has no race window between start
> and completion that may potentially stop HPET timer in some situations.
> 
> Have you tried to enable kern.eventtimer.idletick?
> 
> The best diagnostic would be to get KTR dump at the moment when problem
> begins. You should build kernel with
> options         KTR
> 
> options         ALQ
> 
> options         KTR_ALQ
> 
> options         KTR_COMPILE=(KTR_SPARE2)
> 
> options         KTR_ENTRIES=131072
> 
> options         KTR_MASK=(KTR_SPARE2)
> 
> and as soon as problem begins (before logs wrapped) you should run
> `ktrdump -c -o dump`.
> 
> Also you may try in file acpi_hpet.c change line
> 	if (fdiv < 5000) {
> to the
> 	if (fdiv < 50000) {
> .

Hi Alexander,

thanks for your suggestions. I'll try them out and report then. It might
take some time though.

Stefan