EPOS%20and%20Myrinet:%20Effective%20Communication%20Support%20for%20Parallel%20Applications%20Running%20on%20Clusters%20of%20Workstations

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EPOS and Myrinet Effective Communication Support
for Parallel Applications Running on Clusters of
Workstations

• Antônio Augusto Fröhlich
• Gilles Pokam Tientcheu
• Wolfgang Schöder-Preikschat
• mailtoguto_at_first.gmd.de
• http//www.first.gmd.de/guto
• May 2000

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Outline

• Introduction
• Application-orientation systems
• Component-based systems
• EPOS
• Design
• Framework
• Generation
• Tools
• Conclusion

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Introduction
high performance X all purpose, global, generic

• There is no best general solution
• Each (class of) application has particular demands

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Applicaiton-orientation

• Each application deserves its own run-time
  support system
• Set of applications that will run on top of the
  operating system and their requirements
• Isnt known until run-time gt dynamic adaptation
• Can be determined before run-time gt static
  configuration
• Parallel and embedded applications
• Adaptability and configurability
• Component-based?

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Component-orientation
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The Gap to Applications(Motivation for EPOS)
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EPOS Embedded Parallel Operating System

• EPOS operating system
• Application-driven assemblage of system
  components
• EPOS components
• Statically configurable, application ready system
  abstractions
• EPOS and the real world
• Intelligent visual tools for configuration
• Invisibility
• Standard libraries (Posix files, libc, libstdc,
  libm)
• Standard APIs (Posix threads, MPI)

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EPOS System Abstractions

• Application ready components
• Independent from execution scenario
• Examples
• A thread on a given scheduling policy
• NOT a thread for one processor, or for
  multi-tasking

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EPOS Scenario Adapters

• Adapt existing system abstractions for a given
  execution scenario
• Adapt system micro-components to grant the
  semantics dictated by a given execution scenario
• Examples
• An SMP adapter
• A secure remote invocation adapter

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EPOS Inflated Interfaces

• Export system abstractions to applications
• Well-known to application programmers
• Comprehensive
• Promote requirement analysis
• Examples
• thread
• communicator
• synchronizer
• Not a fat interface
• if intersection gt subset

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Partial and Selective Realization Relationships

• System configuration is basically restricted to
  the setting of selective realize keys

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EPOS Framework

• Static metaprogrammed
• Metaprograms run at compile-time
• (Almost) no run-time overhead
• Implemented as C templates
• System abstraction implementation

• Wrapped
• No allocation or sharing control
• No cross-domain invocation
• Always embedded in the application

• Controlled
• Allocation and sharing control is possible
• Cross-domain invocation is possible
• Embedded in the application or packed in a kernel
  

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EPOS FrameworkWrapped System Abstraction
Application
inflated interface
wrapper
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EPOS FrameworkControlled System Abstraction
Application
ltltselectgtgt id
basic stub
ltltselectgtgt message
message exchange stub
procedure call stub
Inflated interface
ltltselectgtgt stub
handle
ltselectgtgt scenario adapter
ltltselectgtgt id
ltltselectgtgt server
ltltselectgtgt realization
state
message exchange server
procedure call server
basic server
System
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Automatic Generation

• Application refers to inflated interfaces
• Requirement analyzer parses the application
  searching for inflated interfaces references
• Which interfaces are referred to?
• How they are referred to?
• Expert system select the realizations that better
  match the referred inflated interfaces
• An application-oriented operating system is
  compiled

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Requirement Analysis
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Requirement Analysis
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Context Information

• We need context information
• new Thread(task, func) gt location?
• mailbox ltlt message gt protocol?
• Absence of Task gt single-task?
• Buildup databases
• Scenario dependencies
• Target machine description

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Execution Scenario


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Application-oriented EPOS
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Conclusions

• EPOS doesnt grant the tailored OS to be optimal
• When several realizations fulfill the
  requirements, the selection is arbitrary
• Profiling could help
• EPOS framework overhead is close to zero
• Tools are being implemented
• System abstraction repository is growing
• First real applications are being negotiate

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