Re: Ktimer / -rt9 (+custom) monotonic_clock going backwards.

[Steven Rostedt <rostedt@goodmis.org>]

On Fri, 21 Oct 2005, Thomas Gleixner wrote:

> On Fri, 2005-10-21 at 02:03 -0400, Steven Rostedt wrote:
> > On Thu, 20 Oct 2005, Ingo Molnar wrote:
>
> > With rc4-rt13 and changing cycle_t to u64, my machine ran all night
> > without one backward step.  Since it use to show up after a couple of
> > hours, I would say that this is the fix.
> >
> > John, Do you want me to take a crack at changing the periodic_hook into
> > using the ktimer code?  I understand Ingo's kernel much more than you, but
> > you definitely understand the timing code better than I.
>
> Steve,
>
> I think the hook is too complex to move it into the timer interrupt
> context. We still have to reimplement the dynamic priority adjustment of
> the ktimer softirq in a clean way. Once this is done, we can move it
> over and set a proper priority up for that.
>

OK, but the u64 cycle_t should stay.  Even with the dynamic priority of
the softirq, a process with a super high priority that doesn't care about
the timing code can still make the periodic_hook delay for a few seconds.

-- Steve