[ntp:questions] ntpd and database servers

David Woolley david at ex.djwhome.demon.invalid
Thu Jan 14 23:42:46 UTC 2010


nodata wrote:

> Would you mind explaining the link between CONFIG_HZ and the tick value? 
> The example in the man page is not clear (it uses the same tick value as 
> I have on a CONFIG_HZ=1000 box). Is the statement "Increasing val by 1 
> speeds up the system clock by about 100 ppm, or 8.64 sec/day." always 
> true, whatever the CONFIG_HZ value?


The ppm value should be 1000000 * ((modified tickadj value - default 
value) / default value).

The raw internal value of tick should be 1000000 / HZ (with some 
rounding).  I don't know if the adjtimex command line tool does any 
fudging, as I run a traditional 100Hz machine.  The API level tick is 
the same.  This is true for 2.4 series kernels.





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