Re: [RFC] New Time of day proposal (updated 9/2/04)

Christoph Lameter
2004-09-07T16:16:45Z

On Sat, 4 Sep 2004, Andi Kleen wrote:

> On Fri, Sep 03, 2004 at 01:11:58PM -0700, john stultz wrote:
> > The timeofday_hook (should be timeofday_interrupt_hook, my bad) is
> > called by the semi-periodic-irregular-interval(also known as "timer")
> > interrupt. Its what does the housekeeping for all the timeofday code so
> > we don't run into a counter overflow.
> >
> > monotonic_clock() is an accessor that returns the amount of time that
> > has been accumulated since boot in nanoseconds.
>
> Ok, but you need different low level drivers for those. The TSC is not
> stable enough as a long term time source, but it is best&fastest for
> the offset calculation between timer interrupts.

I thought the NTP daemon etc would even that out? ITC (TSC on IA64) is
used by default on IA64 for all time keeping purposes. The CPU has on chip
support for timer interrupt generation.