[ntp:questions] Linux clocksource

unruh unruh at wormhole.physics.ubc.ca
Tue Aug 24 03:37:07 UTC 2010

On 2010-08-23, shane-dated-2010 at csy.ca <shane-dated-2010 at csy.ca> wrote:
> Hey all,
> I am running ntpd under Linux which defaults to using TSC for it's
> clocksource. I also have acpi_pm and hpet available to me and am wondering
> what the current best practice for ntpd is. The issue with TSC seems to be
> that the drift value differs every time I reboot so it goes pretty weird
> when ntpd first starts but then settles after a few hours. I get a stable
> drift with acpi_pm and hpet but from reading the kernel list, I understand
> using TSC is the most efficient way to go as there might be many
> gettimeofday() calls per second and you want those to be fast.

YOu do not say which kernel you are using. I believe that the problem
with tsc has been fixed in later kernel versions. 

Try using chrony. Far faster at convergence, far smaller error after

> So just curious what others are doing here.
> Best,
> Shane

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