[Ns-developers] [ns3] a synchronous socket/posix API

[Mathieu Lacage]

On Sat, 2008-04-05 at 18:21 +0100, Gustavo Carneiro wrote:

>         yes, documentation is needed there. But to answer your
>         question, the
>         expectation is that this class is used to modelize the time of
>         execution
>         of each process. I suspect that most people won't care and
>         will be happy
>         with the default here which is to measure the execution time
>         of the code
>         we are running and use this as the execution time of the code
>         we are
>         modelizing. I have known crazy people who wanted to use more
>         fancy
>         models based on measurements of instruction counts of real
>         world code.
> 
> This is interesting, but I think it should apply also to regular event
> based async simulations.  For instance, when simulating OLSR with many
> nodes, the time spend doing routing table or MPR set computations
> becomes far from negligible.

Certainly: all your model has to be is to implement a delay model and
use it to calculate event expiration times or to perform power
management. That is a lot of work for most model developers though.

> 
> On the other hand, modelling process CPU time by measurements of CPU
> time spent on a simulator running on a Xeon processor may provide
> timings that are far from a real world implementation running on a
> much slower ARM CPU.

Sure.

> 
> So, very good intentions, but the problem is more complex to solve
> fully. :-/

I just put in something which works, is simple and never claimed I
solved the problem fully. Feel free to add more fancy delay calculation
models if you are interested in this by adding extra subclasses of this
base class.

Mathieu