An ontology of clocks
Hal Murray
hmurray at megapathdsl.net
Mon Feb 22 11:25:40 UTC 2016
kurt at roeckx.be said:
> I'm sure what you mean by corrupt in the case of suspending. It's still
> measuring something, but maybe not something you (or ntp) cares about. I
> guess this falls under your category of "clocks that count time
> selectively".
Some clocks get turned off when suspended to save power. Details vary. It
takes time to get the crystal started so you may not want to turn it off
between keystrokes.
kurt at roeckx.be said:
> There is also at least /dev/hpet that you might want to look at.
Most of that sort of clock are all derived from the main CPU crystal which
generates several clocks via PLLs.
For the detail collection...
The CPU clock and friends are probably smeared slightly to dance around the
FCC's EMI rules. That means wiggling the frequency slightly. I think the
wiggle is typically in the ballpark of 50kHz. It's slow enough so that PLLs
can track it and fast enough to keep the FCC happy.
--
These are my opinions. I hate spam.
More information about the devel
mailing list