Re: [Xenomai-core] Monotonic, realtime, and other timers

[Jan Kiszka <jan.kiszka@domain.hid>]

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Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>  > Gilles Chanteperdrix wrote:
>  > > Jan Kiszka wrote:
>  > >  > Gilles Chanteperdrix wrote:
>  > >  > > IMO, the only advantage of having absolute timers is to be able to apply
>  > >  > > the posix scheme. So, if I followed correctly your discussion, what we
>  > >  > > need is:
>  > >  > > - an XNTBISOL flag with a service xntbase_isol which set this flag and
>  > >  > >   unshare the target timebase if it is shared (IOW, if aperiodic)
>  > >  > > - the service xntbase_adjust_time to walk all the absolute timers of the
>  > >  > >   non isolated timebases and adjust their expiry date or play their
>  > >  > >   handler the posix way.
>  > >  > 
>  > >  > Two questions came up here regarding item #2:
>  > >  > 
>  > >  >  - Shouldn't we also adjust the non-monotonic timers of an isolated base
>  > >  >    if it asks for wallclock tuning? I think so.
>  > >  > 
>  > >  >  - We don't have a service to walk the list of all pending timers, do
>  > >  >    we? As that touches all of our timer queue variants and I'm not
>  > >  >    familiar with their details (except for plain lists...), I would
>  > >  >    welcome any support on this.
>  > > 
>  > > I am afraid for other things than lists, we will have to define an
>  > > xntimerq_iterator which holds a little bit more information than just a
>  > > pointer to a holder.
>  > > 
>  > 
>  > So we would have to increase the size of each xntimer_t object? Argh.
>  > 
>  > Sounds a bit like it's worth to have a closer look at some "two timer
>  > lists, one with adjustable offset"-approach...
> 
> No, I was thinking about defining a new type xntimerq_iterator, whose
> sole purpose would be to hold the state of an iteration. In fact, we
> only need this in the hashed case, binary heap holders already contain
> enough information.
> 

OK, if that will not have negative impact on existing code, so much the
better.

Meanwhile I uploaded my current patch stack to
http://www.rts.uni-hannover.de/rtaddon/patches/xenomai. I'm going to
comment on detail aspects later. Just so much: it /should/ be finished
except for the yet empty placeholder re-adjust-timers.patch.

Jan


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