Post on 18-Dec-2014
description
CSE539: Advanced Computer Architecture
Chapter 9
…Dataflow Architectures Book: “Advanced Computer Architecture – Parallelism, Scalability, Programmability”, Hwang & Jotwani
Sumit Mittu
Assistant Professor, CSE/IT
Lovely Professional University
sumit.12735@lpu.co.in
In this chapter…
• Evolution of Dataflow Computers
• Dataflow Graphs
• Static v/s Dynamic Data Flow Computers
• Pure Dataflow Machines
• Explicit Token Store Machines
• Hybrid and Unified Architectures
• Dataflow v/s Control flow Computers
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 2
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 3
• Data-driven machines
• Evolution of Dataflow Machines
• Dataflow Graphs o Dataflow Graphs examples.
o Activity Templates and Activity Store
o Example: dataflow graph for cos x
• 𝐜𝐨𝐬 𝐱 ≅ 𝟏 − 𝒙𝟐
𝟐!+
𝒙𝟒
𝟒! −
𝒙𝟔
𝟔!
o More examples
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 4
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 5
• Static Dataflow Computers o Special Feedback Acknowledge Signals between nodes
o Firing Rule:
• A node is enabled as soon as tokens are present on all input arcs and there is no token on
any of its output arc
o Example: Dennis Machine (1974)
• Dynamic Dataflow Computers o Tagged Tokens
o Firing Rule:
• A node is enabled as soon as tokens with identical tags are present at each of its input arcs
o Example: MIT Tagged Token Dataflow Architecture (TTDA) machine (just simulation, never built)
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 6
• Diagrams of static dataflow and dynamic dataflow
• from Hwang and Briggs….
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 7
• Pure Dataflow Machines o TTDA (1983)
• TTDA was simulated but never built
o Manchester Dataflow Computer (1982)
• Operated asynchronously using a separate clock for each PE
o ETL Sigma-1 (1987)
• 128 PEs fully synchronous with a 10-Mhz clock
• Implemented I-structured memory proposed in TTDA
• Lacked High Level Languages for users
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 8
• Explicit Token Store Machines o Eliminate associative token matching.
o Waiting token memory is directly accessed using full/empty bits.
o Examples
• MIT/Motorola Monsoon (proposed 1988; operational 1991)
o Multithreading support
o 8 processors
o 8 I-structure memory modules
o 8x8 crossbar network
• ETL EM-4 (1989)
o Extension of Sigma-1
o Proposed 1024 nodes; Operational Implementation 80 nodes
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 9
• Hybrid and Unified Architectures o Combining Features of von-Neumann and Dataflow architectures
o Examples:
• MIT P-RISC (1988)
• IBM Empire (1991)
• MIT/Motorola *T (1991)
o “RISC-ified” dataflow architecture
• Implemented in P-RISC
• Splitting complex dataflow instructions into separate simple component instructions
• Tighter encoding and longer threads for better performance
• Dataflow Processing v/s Control Flow Processing
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 10
• Computing ab + a/c with: (a) control flow; (b) dataflow. Pure dataflow basic execution pipeline: (c) single-token-per-arc dataflow;
(d) tagged-token dataflow; (e) explicit token store dataflow
DATAFLOW AND HYBRID ARCHITECTURES
Sumit Mittu, Assistant Professor, CSE/IT, Lovely Professional University 11
• Computing ab + a/c with: (a) control flow; (b) dataflow. Pure dataflow basic execution pipeline: (c) single-token-per-arc dataflow;
(d) tagged-token dataflow; (e) explicit token store dataflow