Clock running at half speed in 2.6.20?

From: Adam J. Richter
Date: Fri Feb 16 2007 - 09:27:06 EST

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 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,

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
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at