Re: 2.6.14-rt21: slow-running clock

From: john stultz
Date: Mon Dec 05 2005 - 14:42:03 EST


On Mon, 2005-12-05 at 16:56 +1030, Jonathan Woithe wrote:
> Hi all
>
> When running Ingo's 2.6.14-rt21 (and in fact rt kernels back to at least
> 2.6.13-rc days), the clock on my i915-based laptop runs slow. The degree
> of slowness appears directly related to how busy the machine is. If
> it is just sitting around doing very little the time is kept rather
> well. However, as soon as the load increases the RTC and system time
> diverge significantly. For example, running jackd for 2 minutes results
> in the system time loosing as much as 20 seconds compared to the CMOS RTC.
> Processes doing HDD I/O also seem to affect the system time similarly.
>
> Selectively disabling different timer-related kernel options does not make
> any difference. However, the clock seems fine under vanilla 2.6.14,
> suggesting an issue somewhere in the rt patches.

Could you please send me your dmesg and the output of:

cat /sys/devices/system/clocksource/clocksource0/*


Thanks
-john


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