Re: fast clock wreaks havoc on amd64 dual core - hp1250n
Am Samstag 22 Oktober 2005 03:52 schrieb Nathan O. Siemers:
> Hello all,
>
> I've spent the last 5 days trying to fix an issue with a brand new
> hp a1250n dual core athlon64 machine. ATI motherboard with embedded
> radeon xpress 200 graphics. I've installed the pure64 sarge
> distribution. This is my first 64 bit debian attempt, although I am
> running a 2 cpu opteron workstation with suse at work.
>
> The system in many ways okay, but there is a serious problem with
> interrupts and clock speed which wreaks general havoc on the machine.
> The clock is running about 2x speed - I think perhaps two clock ticks
> (from each core?) are happening for each one that should. X windows
> keyboard behavior is quite erratic, I often get 2-4 chars repeated for
> each key typed. I believe this is consistent with lots of interrupt
> activity?
>
> Summary of my experiments so far:
>
> 2.6.13.4 kernel
>
> 1. turning off smp in kernel compile configuration does not correct the
> problem.
>
> 2. no_timer_check and/or notsc does not reliably correct the problem - I
> have seen some help for periods of time.
>
> 3. moving from athlon64 to generic x86_64 during kernel compile does
> nothing
>
> 4. no_timer_check pci=noacpi pci=routeirq kernel boot option corrects
> the 2x clock speed problem, but breaks at lot of other things - I am
> running this at the moment so I can use the computer (but my firewire
> drive is not recognized, for example).
>
> 5. PM_timer kernel compile option does nothing
>
> 6. Changing timer frequency does nothing.
>
> I wanted to check with older 2.6 kernels but experience a failed boot on
> stock debian 2.6.8 amd64-smp kernel, I don't this is indicative of a
> problem other than misconfiguration of grub or devfs subsystems (there
> is a pivot_root at boot time that fails)...
>
> some interesting log entries:
>
> kern.log:
> Oct 18 14:57:48 localhost kernel: Losing some ticks... checking if CPU
> frequency changed.
>
> Oct 18 23:36:50 line kernel: Your time source seems to be instable or
> some driver is hogging interupts
> Oct 19 05:40:05 line kernel: rtc: lost some interrupts at 2048Hz.
> Oct 19 05:49:33 line kernel: rtc: lost some interrupts at 2048Hz.
>
> This seems like it could be related to kernel bug 3927:
>
> http://bugzilla.kernel.org/show_bug.cgi?id=3927
>
> which has been marked as "resolved" but my reading suggest that a
> sufficient number of people found workarounds to let the bug subside
> rather than fixing it...
>
> In any case, my deep appreciation to anyone who has a solution after
> days of kernel recompiles and rebooting with various boot options.
> Happy to send more detailed logs and kernel compile options if there is
> interest.
>
> Nathan
Just a little workaround.
You need an smp numa kernel. Compile it this 500 hz.
Markus
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