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The Architecture Simulator

The architecture simulator is capable of simulating a distributed system consisting of processing nodes using an interconnection network. The nodes communicate with each other by sending messages over the network. Every node in the architecture simulator corresponds exactly to a partition in the parker. The architecture simulator has three tasks:

• Executing the partition at every processor node. The simulator has to check at regular intervals whether the simulated time for one node is not advancing too much with respect to the other nodes in the system. If a certain margin has been exceeded, the running node is suspended in order to allow the other nodes to catch up. This is vital for simulations that have nodes with unbalanced work load.

• Handling the messages that are sent from one node to another. To accurately calculate the communication performance, the simulator uses a realistic model of the architecture. Message passing is based on the OSI model for computer networks, and covers the transport, network and data link layers. The simulator allows the user to vary a number of parameters for each of those layers. The current version of the simulator uses E-cube routing in a 2-D mesh topology, but more topologies and routing strategies are expected to be developed in the near future.

• Performance analysis of the processor nodes and communication channels. By means of a configuration file, it is possible to selectively monitor a number of events in the simulator. The results are written to a trace file, which can subsequently be analysed by further tools, allowing the user to extract many different aspects of the architecture performance.