Myrinet 2Gbps Networks (http://www.myri.com)

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Myrinet 2Gbps Networks(http//www.myri.com)
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Overview

• Myrinet is a high-performance, packet-communicatio
  n and switching technology that can be used to
  interconnect clusters of workstations, PCs,
  servers, or single-board computers.
• Cluster computing has the following advantages
• high performance
• high availability
• Cluster computing needs
• High throughput bulk data transfer
• Low latency message passing

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Pictures of Myrinet
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Myrinets Features

• Full-duplex 22 Gigabit/second links, switch
  ports, and interface ports
• Flow control, error control, and "heartbeat"
  continuity monitoring on every link
• Low-latency, cut-through, crossbar switches, with
  monitoring capability
• Switch networks that can scale to tens of
  thousands of hosts
• Host interfaces that execute a control program to
  interact directly with host processes ("OS
  bypass") for low-latency communication, and
  directly with the network to send, receive, and
  buffer packets

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A Possible Configuration
Two computers can also be connected directly
through a cable.
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Packet Format and Routing
Source routing
An IP packet can be carried by a Myrinet packet
as its payload.
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Deadlocks May Form

• Source routing is used.
• A network mapping program needs to be run on one
  host to discover the map of the network. It then
  distributes the map to all other host
  interfaces.)
• Cut-through switching is used to reduce message
  latency. (wormhole routing)
• For high-performance distributed application
  programs, latency will be more important than
  throughput (because latency cannot be improved
  whereas throughput can be improved.)
• Thus deadlock situations may form.
• Myrinet thus provides a monitoring and timeout
  mechanism to break deadlock situations.

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Myrinet Host Interface
1995 version

• We can write the firmware source code, compile
  it, download it, and run it on the host
  interface!!!!

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Myrinet Host Software

• Myrient can use zero-copy and checksum offload
  capabilities to improve transfer throughput.