VisualSim Libraries

Models are constructed in VisualSim Architect using a set of building blocks in a UML-like graphical block diagram editor. A block can be basic structure such as a distribution-based stimulus generator or a complex component like a processor. Each block contains a set of parameters that control their execution. Libraries form the basis of VisualSim modeling capability.

A model is constructed by instantiating the blocks from the library folders on the Block Diagram Editor, editing the parameters and connecting the ports together using a black line resembling wires. For example, the Transaction_Generator block has Start Time, Mean Time and List of Distributions.

Library Description

All blocks in the modeling library support transactions and are data type polymorphic. This means the type of the data to be processing is determined during run-time.  For example a processor or bus can have

as transactions in one model and can have for another model. This flexibility enables the same block or function to be reused in a number of scenarios. The basic blocks, such as the Mathematical Functions block, have about 10 different operating modes, while the more complex blocks, such as the Multi-dimension Priority Queue and Processor, can have 45 different modes of operation.  A mode of operation is established based on parameter setting of the block.

The multi-mode operation and the polymorphism substantially reduce the number of blocks that need to be present in the library by a factor of 25.  This also reduces the number of blocks that need to be instantiated in a model window, thus enabling large and extremely high performance models to be created with minimal memory consumption. This important capability reduces the learning curve for a new user of VisualSim.

Standard Library

Sources: This library provides the user the ability to construct traffic models that can be executed at different levels of abstraction. The liubrary contains representation for distribution-based, sequences, trace file, clocks, and signals.

Analysis and Results: Over 3000 statistics are built into the resources and architecture library components. In addition, this library enables users to construct custom statistics such as intermediate latency or throughput/packet size vs. Latency. In addition, this library provides blocks that enable interactive display of the results in the form of graphs and text displays.

Resources: This library contains queues, channels, pipelines, schedulers and server. The components are used to define the resources in a performance or traffic model that consume time or quantity. These can represent a network or wireless channel, processor or a large system such as a satellite. Models built with resources can be cycle-accurate detail and can be fairly accurate without requiring a knowledge of the underlying implementation. This library forms the foundation of the performance modeling, traffic analysis and the Transaction Level modeling capability of VisualSim. The blocks can be shared or distributed and contain complex scheduling algorithms such as First Come-First Serve, Round-Robin and Preemption.  All of the blocks in this library generate statistics for the buffer usage, utilization, data arrival and departure rate, transitions and processing latency.  All varieties of hardware and software resources can be described using the blocks available in this Resource Library.

Processing: The C-like scripting language and associated modeling API functions provide a comprehensive approach to describing the logic, interaction between resources, behavior and arbitration.

Finite State Machine: This is a UML-like graphical representation of the State Chart View. The state charts can be hierarchical for the definition of the states and transition. In addition, the states can have performance information associated with them, thus making it uniquely timed.