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
On Tue, 2006-11-28 at 21:46 -0200, Alexandre Pereira Nunes wrote:
> 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
Hmmm. Could you send me your dmesg? Also what frequency is your cpu?
Also does booting w/ "noapic" change the behavior?
> 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 ;
I think you mean "current_clocksource" there...
> 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.
Yea, its likely the generic timekeeping changes for i386. Previously
(pre-2.6.18) it probably defaulted to the acpi pm timer and was fine.
The new code is a bit more aggressive in trying to use the TSC.
As a short term workaround, you can put "clocksource=acpi_pm" on your
grub line and that will force the clocksource at boot.
thanks
-john
processor : 0
vendor_id : AuthenticAMD
cpu family : 6
model : 8
model name : AMD Athlon(tm) XP 2600+
stepping : 1
cpu MHz : 2133.046
cache size : 256 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 mmx fxsr sse syscall mmxext 3dnowext 3dnow up ts
bogomips : 4270.91
[cut]
>
>Also does booting w/ "noapic" change the behavior?
>
>
No, it didn't. It behaves exactly as before.
- Alexandre