Dataflow Machines - Computer Systems Architecture - Lecture Slides, Slides of Computer Architecture and Organization

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Dataflow Machines

Presentation Outline

• What is data flow technique?
• History of Data Flow Machines
• Data Flow Models
• Types of Data Flow Systems
• Macrodataflow
• Conclusion

Data Flow Technique

• Alternative computer design to stored program systems.
• The Difference
  • Traditional Methods An instruction executed when the previous instruction in a defined sequence has been executed
  • In this model, It is executed when the operands required become available.

History

• developed in 1960s by Karp and Miller as graphic means of representing computations.
• In the early 1970s Denis and others began to develop computer architectures based upon the dataflow computational model.

Terminology

Data, data dependency graph Arcs : flow of the data Nodes : represent operations Token : represent data and operations Firing : when data is available, operation is started, then result is sent to destination. Handshaking: Result is consumed

Data flow example

Loop graph

Static dataflow

• Recursion is not implemented
• Each node can fired only as once instance
• Firing rules

Token format in static

OPCODE OPERAND DESTINATION

VALUE DESTINATION

PE receives operation packes of the form

PE sends packets of the form

static dataflow diagram

Dynamic data flow architecture

Disadvantages of dynamic dataflow

• Overhead involved in matching tokens is heavy
• Resourse allocation is a complicated process
• The long instunction cycle

Pure Dataflow machines

Hybrid data flow Docsity.com