Re: Detecting shift of CLOCK_REALTIME with clock_nanosleep (again)

Scot Salmon
2012-11-15T19:28:13Z

Thomas Gleixner <tglx@linutronix.de> wrote on 10/31/2012 03:08:45 PM:
> What you are concerned about is keeping the machines in sync on a
> common global timeline. Though your more fundamental requirement is
> that you get the wakeup on each machine in the given cycle time. The
> global synchronization mechanism just adjusts that local periodic
> schedule.
[...]
> What you really want is an atomic readout facility for CLOCK_MONOTONIC
> and CLOCK_REALTIME. That allows you to align the CLOCK_MONOTONIC based
> timer with the global CLOCK_REALTIME based time line and in the event
> that the CLOCK_REALTIME clock was set and jumped forward/backward you
> have full software control over the aligning mechanism including the
> ability to do sanity checking.

This works for me. We discussed it on IRC and agreed on "something
like clock_gettime2(id, id, *t1, *t2) with a sanity check on the ids,
that allows us other combinations than MONO/REAL as well".

-Scot