[ntp:questions] Can NTP affect the time even when not running? (with platform details this time)
brad at stop.mail-abuse.org
Wed Nov 24 15:17:04 UTC 2004
At 12:26 AM +1300 2004-11-25, Parker Jones wrote:
> Platform: linux Fedora Core 2, kernel 2.6.8-1.521, ntp-4.2.0-7 on NEC
> Versa LX 400MHz laptop
Laptops are notorious for having "speed-step" type of technology
that speeds up or slows down the processor as necessary for the
workload and cooling requirements, and this plays holy hell with good
timekeeping. You shouldn't be trying to run ntpd on a laptop unless
you lock the processor to a given speed. It doesn't matter too much
what speed you lock to, just so long as ntpd is given a consistent
speed at which the CPU runs.
If you do try to run ntpd on a laptop and you don't lock the
processor to a given speed, you can anticipate all sorts of weird
problems, and ntpd may calculate strange correction values which may
be left over after you stop running it, and these values may then be
applied inappropriately to free-running mode.
If this isn't already in the FAQ, it should be.
Brad Knowles, <brad at stop.mail-abuse.org>
"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
-- Benjamin Franklin (1706-1790), reply of the Pennsylvania
Assembly to the Governor, November 11, 1755
SAGE member since 1995. See <http://www.sage.org/> for more info.
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