2.6.18 tsc clocksource + ntp = excessive drift; acpi_pm does fine.

From: Alexandre Pereira Nunes
Date: Tue Nov 28 2006 - 18:46:50 EST


Hi,

with default boot I got tsc clocksource selected on an debian's 2.6.18-3-k7 SMP build (but UP machine). ntp keeps bothering me with this message:
frequency error 512 PPM exceeds tolerance 500 PPM

If I remove ntp's drift file and restart, it goes fine for a while and then it goes with that behaviour again.
If I remove ntp's drift file, then do a: echo acpi_pm >/sys/devices/system/clocksource/clocksource0/available_clocksource ; and then restart ntp, it goes fine "forever".

Any toughs, something I should look at?

I'll be glad to give more feedback.

I don't know if that happened with 2.6.17, but I'm pretty sure that with 2.6.16 it was fine.

- Alexandre
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