On Tue, 17 Dec 2013, Eliezer Tamir wrote:
> On 17/12/2013 17:13, Peter Zijlstra wrote:
> > On Tue, Dec 17, 2013 at 04:03:58PM +0200, Eliezer Tamir wrote:
> >>
> >> I'm not sure that subtracting the spin time is the optimal thing to do.
> >>
> >> The busy poll time is supposed to be limited to something less than 1ms.
> >> (I'm using 50us in most of my tests)
> >> This is typically orders of magnitude smaller than the poll timeout.
> >> Would it make more sense to just enforce a limit on poll time?
> >>
> >> What do you think?
> >
> > I've no idea what people normally expect of select/poll wakeup
> > granularity but typically we already have 50us of timer slack, although
> > RT tasks go without this.
>
> If RT tasks can't accept 50us of fuzziness, then the
> path of least astonishment would be to have fully accurate
> timekeeping, as you suggested. OK, so that's the plan.
No, the plan is to avoid busy loops in the first place.
Thanks,
tglx
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