changesets:10877:51af672c9841

dev: Add a network switch model for pd-gem5
This patch adds a network switch model to be able to work for pd-gem5 extension
http://reviews.gem5.org/r/2305/ is used as a template. We modified it to make

it work for pd-gem5 extention. Here is the list modifications:
-Simplified packet arbitration by using a zero delay switch fabric (crossbar)

-Removed input queues

-Reorder packets on each interface based of packet time-stamp

-Predict queuing/congestion delay on each interface

-Apply switch timing parameters (latency + queuing delay) to packet time-stamps