[ntp:questions] Re: time

Per Hedeland per at hedeland.org
Thu Dec 1 22:21:46 UTC 2005

In article <m3hd9s7fy1.fsf at lysator.liu.se> Bjorn Gabrielsson
<bg at lysator.liu.se> writes:
>CBee <I.Dont at want.your.spam> writes:
>> Once again, yep, linux has an internal clock that counts the
>> miliseconts and it travels all of them. However, who tells me each
>> milisecond actually takes 1000 microseconts?
>Strange... since ntp get 1us resolution timetagging the pps-pulse from
>a gps. :-) Are you _really_ sure of your statements?  (HZ is not the
>same as the 'clock'.)

The system clock runs at HZ on all Unix systems. This does not preclude
the possibility of obtaining time stamps with higher resolution by
interpolating various timers or counters that may or may not be
available on your particular HW platform, and may or may not actually be
interpolated by your particular Unix version. I guess a useful
definition of "system clock" would involve some wording about "the
granularity with which you can schedule events".

--Per Hedeland
per at hedeland.org

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