Welcome to the WebHASE simulation model of a Stanford DASH architecture Cluster. The applet may take some time to load
The Cluster simulation model contains four nodes attached to an MPBus. The MPBus is one of the most complex entities in the simulation. It is responsible for displaying a large amount of state information detailing the on-going operation of the snoopy-bus protocol as well as carrying out the conventional tasks of bus arbitration, address and data transfer.
The cluster memory is relatively simple in design. Because the simulation is only concerned with modelling the effects of read/writes throughout the system (and not the contents of memory locations) no actual storage needs to be modelled other than that present in the processor caches (and in these only addresses need be stored). Therefore a memory unit cycle consists of receiving an in-bound request, displaying read/write information on-screen and finally transmitting the result packet back onto the MPbus.
The applet model contains a sequence of accesses in each of the four nodes. As an exercise, students are asked to play the simulation in single shot mode and to observe what happens in the model in response to each of the accesses.
hase@dcs.ed.ac.uk