Agenda

• Convergence of parallel architectures
• Fundamental design issues
• ILP vs. TLP

Communication architecture

• Historically, parallel architectures are tied to programming models
  • Diverse designs made it impossible to write portable parallel software
  • But the driving force was the same: need for fast processing
• Today parallel architecture is seen as an extension of microprocessor architecture with a communication architecture
  • Defines the basic communication and synchronization operations and provides hw/sw implementation of those

Layered architecture

• A parallel architecture can be divided into several layers
  • Parallel applications
  • Programming models: shared address, message passing, multiprogramming, data parallel, dataflow etc
  • Compiler + libraries
  • Operating systems support
  • Communication hardware
  • Physical communication medium
• Communication architecture = user/system interface + hw implementation (roughly defined by the last four layers)
  • Compiler and OS provide the user interface to communicate between and synchronize threads