Algorithms%20in%20a%20Multiprocessor%20Environment

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Algorithms in aMultiprocessor Environment

• Kevin Frandsen
• ENCM 515

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Outline

• Introduction
• Algorithms
• Communication Models
• Common DSP Uses
• Conclusion

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Introduction

• What are Multiprocessor Cores?
• Two CPUs Same Silicon
• Equal Capability
• Shared Memory
• Tighter Access

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Introduction cont.

• Other Multiprocessing Options
• SMP
• Usually Two on same board, not silicon
• Shared Memory
• Limited access to each other
• Clustering
• Independent processors
• Communication Medium
• NUMA

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Algorithms

• Finite Impulse Response (FIR) Filter
• Common DSP Algorithm
• Specialized hardware exists

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Algorithms cont.

• More on FIR
• Divide and Conquer
• O(n)/p time
• Shared memory/registers a plus
• Reduced communication overhead

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Algorithms cont.

• Matrix Operations
• Common algorithms on large sets

A11 A12 A1n B11 B12
B1n C11 C12 C1n A21
A22 A2n B21
B22 B2n C21 C22
C2n X

Am1 Am2 Amn Bm1
Bm2 Bmn Cm1 Cm2 Cmn
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Algorithms cont.

• Matrix Multiplication
• Large data transfers necessary in non-shared
  environments
• If not bandwidth limited, scales well with
  processors
• Matrix Inversion
• Larger data loads

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Communication Models

• Shared Memory
• Fast
• Few concurrency problems
• Still some, race conditions, etc.
• Need to be on same board
• Custom designed
• Need secondary synchronization Mutexes,
  Semaphores

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Communication Models cont.

• Message Passing (PVM, MPI, etc)
• Flexible implementations
• Self-synchronizing
• Communication overhead (large)

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Common DSP Uses

• Shared Core and SMP
• Best for real-time response
• Easiest for integrated systems
• ADSP - 21062
• Clustering
• Batch processing
• Images, 3D rendering
• SCI at University of Utah

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Scientific Computing Institute

• 3D Visualization of Brain Tumor

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Conclusion

• How multiprocessing affects tasks
• Ways of implementing a multiprocessing system
• Uses in the real world

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Questions?
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References

• University of Utah. (2004, February 28).
  Applications Tumor Visualization Scientific
  Computing and Imaging Institute. Retrieved April
  10, 2004, from http//www.sci.utah.edu/about/rwa-t
  umor-vis.html
• Dr. Smiths Mar 8 Presentation on Highly Parallel
  FIRs
• Dr. Leons Parallel Computing Course