linux-kernel - Clock running at half speed in 2.6.20?

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Message-Id: <200702161428.l1GESUw9008969@freya.yggdrasil.com>
Date:	Fri, 16 Feb 2007 22:28:30 +0800
From:	"Adam J. Richter" <adam@...drasil.com>
To:	linux-kernel@...r.kernel.org
Subject: Clock running at half speed in 2.6.20?

	My system clock runs at approximately half speed in
linux-2.6.20, 2.6.20-git10 and 2.6.20-git11.  That is, it takes about
two hours for "date" to report that one hour has elapsed.  "hwclock"
returns the correct time, of course.

	I do not have this problem in linuux 2.6.18.1.  I will try to
narrow down the kernel version where this problem began.

	The motherboard in question is an asus p4v8000-x, running a
2.8GHz Pentium 4 that has two hyperthreads, which I suspect may be the
problem.  I am just guessing, but perhaps some piece of code thinks
the two hyperthreads are separate CPU's receving twice as many clock
interrupts total.  I expect to try to some experimentation to check
this theory.

	For what it's worth, I am running CONFIG_PREEMPT=y,
CONFIG_PREEMPT_BKL=y, CONFIG_HZ=1000.

	If there is a more specific mailing list for discussing this
problem, I would be interested in knowning about it.  The MAINTAINERS
file lists several components with the word "clock" in them, but I
believe that all are for drivers for hardware clocks or high
resolution timer extensions.  I tried a quick search of the
linux-kernel mailing list for "clock" in the subject line, and did not
notice anything that seemed like a match to this problem.

	I will post more information as I collect it, but I am posting
this bug report now in case this problem rings a bell for anyone.

Adam Richter
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