Low Cost, High Performance, and Scalability:

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(No Transcript)
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GUARANTEED!

• Low Cost, High Performance, and Scalability
• A New Approach to User-Level Distributed Shared
  Memory

OR YOUR MONEY BACK!!!
Patrick Anthony La Fratta WORTS 2005 15 December
2005
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• Programming Models Message-Passing

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• Programming Models Message-Passing

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• Programming Models Shared Memory

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• Implementing a DSM System at the User Level

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• Implementing the DSM Client

Initialization, Step 1 Get size of shared memory
segment.
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• Implementing the DSM Client

Initialization, Step 2 Map n pages into local
memory.
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• Implementing the DSM Client

Initialization, Step 3 Take away all access
privileges from the shared segments.
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• Implementing the DSM Client

Initialization, Step 4 Set up the segmentation
fault handler.
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• Implementing the DSM System

Application Reads Shared Address Preview
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Implementing the DSM System
Shared address read, Step 1 Application reads
shared address.
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Implementing the DSM System
Shared address read, Step 2 Control transferred
to seg-fault handler.
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Implementing the DSM System
Shared address read, Step 3 Client contacts the
server to get the pages data.
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Implementing the DSM System
Shared address read, Step 4 Client grants read
access privileges to application.
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• Implementing the DSM System

Application Writes Shared Address Preview
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Implementing the DSM System
Shared address write, Step 1 Application writes
shared address.
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Implementing the DSM System
Shared address write, Step 2 Control
transferred to seg-fault handler.
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Implementing the DSM System
Shared address write, Step 3 Client contacts
server to with write notification.
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Implementing the DSM System
Shared address write, Step 4 Server calls back
all other copies of pages being written.
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Implementing the DSM System
Shared address write, Step 5 Server indicates
to client to proceed.
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Implementing the DSM System
Shared address write, Step 6 Client grants
write privileges to application.
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Implementing the DSM System
Shared address write, Step 7 Later, the app
detaches pages so others may use them.
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• Preliminary Results All Pairs Shortest Paths

Note Results matched for all test cases, and all
runs completed successfully.
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System Profiling All Pairs Shortest Paths
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System Profiling All Pairs Shortest Paths
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System Modifications and Extensions
System profiles resulted in

• Better understanding of the trade-offs in
  the design of the interface.
• Efficient synchronization primitives through
  extended memory semantics with full/empty bits.
• Server-side per-page locking and client-side
  full- page flushing.
• Speedups gt 1!

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Performance Results Speedup for Various
Configurations
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Performance Results Trends
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• Future Work

• Scalability Enable clients to use more than
  one server.
• Peer-to-peer Merge the server and client
  modules.
• Fault-tolerance Checkpoint and Migration?
• Further testing Implement and evaluate
  performance of other parallel applications.

Questions?