[Ns-developers] NS3 - Queue Scheduler

[Mathieu Lacage]

hi,

On Tue, 2008-04-01 at 11:23 +0200, Hagen Paul Pfeifer wrote:
> 
> In context with gsoc2008 and the parallelization of NS3 the following
> question arise: are there some major changes in the current queue scheduler
> implementation scheduled? There are major coherences between
> parallelization
> and the scheduler. A "pluggable architecture", or lets say quick changing
> algorithms (or modifications) are not that favorable.
> 
> So at the end: are there some new stars in the sky?

I am not really sure I understand your question exactly but I will try
to answer anyway.

1) In a parallel simulation where you run a set of separate parallel
partitions, there is no constraint on which algorithm and data structure
you use to sort and schedule events within that partition. So, working
on parallel simulations does not mean adding new event scheduling
algorithms and data structures

2) Adding support for parallel simulations which is really transparent
to the user would require that you can ensure the _exact_ same
whole-simulation event ordering in both the parallel and non-parallel
cases. To do this in a not-too-ineficient way will most likely require
that you change the sorting key even in the non-parallel case so, that
will require a few (hopefully small) changes to the current in-tree
schedulers.

So, to summarize, none of the above require that you work on a new event
scheduling algorithm implementation. You will have to change the
'simulator' code (src/simulator/simulator.cc) but, hopefully, will be
able to reuse the 'scheduling' code (src/simulator/scheduler*).

regards,
Mathieu