Re: scheduler going backwards solution?

[Lloyd Wood <eep1lw@surrey.ac.uk>]

On Wed, 8 Sep 1999, Lloyd Wood wrote:

> On Wed, 8 Sep 1999, Sean Murphy wrote:
> 
> > > What is "added desk calendar wrapping feature"?
> > > 
> > > Heap as well as Calendar had a problem with re-ordering of
> > > simultaneous events, but that has been fixed.  Keeping the order the
> > > same is useful for validations and lets different schedulers verify
> > > each other.
> > > 
> > > Calendar is still the default because no one ventured to change it to
> > > Heap.  There is a hope that recent fixes are enough to keep that
> > > 'backwards' error from reappearing.  In theory, Calendar's hold time
> > > (1 enqueue + 1 dequeue) is O(1), which is better than Heap's O(lg(N)).
> > > In practice, there may be not that much difference, though.
> > 
> > I never understood the differences between these different schedulers, but
> > I think I'm beginning to see it now. Am I right in saying that
> > 
> > 1. The Calendar scheduler uses hashing to insert an event into the
> > scheduler queue, and hence it takes O(1) to insert and remove an event
> 
> Apparently so. IMO it would be good to have the year adjustment in
> CalendarScheduler::deque() optionally settable as an otcl parameter
> with period (wrap years?/wrap days?/wrap hours?), rather than as the
> default.

...on the other hand, I don't know what I'm talking about; this could
be a bizarre performance tweak.

L.

<L.Wood@surrey.ac.uk>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>