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Scalable Multi-Precision Simulation of Spiking Neural Networks on - - PowerPoint PPT Presentation

Scalable Multi-Precision Simulation of Spiking Neural Networks on GPU with OpenCL Dmitri Yudanov (Advanced Micro Devices, USA) Leon Reznik (Rochester Institute of Technology, USA) WCCI 2012, IJCNN, June 12 Agenda Motivation OpenCL.


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SLIDE 1

Scalable Multi-Precision Simulation of Spiking Neural Networks on GPU with OpenCL

Dmitri Yudanov

(Advanced Micro Devices, USA)

Leon Reznik

(Rochester Institute of Technology, USA) WCCI 2012, IJCNN, June 12

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SLIDE 2

 Motivation  OpenCL. SNN Simulation Platform  GPU Device Architecture  SNN Simulation Architecture  Results:

Verification and Performance

 Next Simulator Architecture  Conclusion  Q&A

Agenda

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SLIDE 3

 SNN simulation scalability domains:

  • Network size
  • Connection count
  • SNN component models (neuron, synapse, gap junction etc)
  • Simulation methods (event-driven, time-driven, numerical methods)
  • Precision

 Simulation flexibility and programmability for

heterogeneous environment. OpenCL.

 Configuration:

  • GPU Radeon™ HD 7970 (code-named Tahiti). OpenCL
  • Izhikevich neuron model
  • Parker-Sochacki simulation method

Motivation

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SLIDE 4
  • OpenCL. Simulation Platform

Open Computing Language. Open standard maintained by Khronos Group

Four models:

Platform model

Memory model

Programming model

Execution model

Based on B Gaster et al. Heterogeneous Computing with OpenCL.: Morgan Kaufmann Pub, 2011.

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SLIDE 5

Tahiti GPU Architecture: High Level View

Based on AFDS11 presentation: M Houston and M Mantor. (2011, June) Fusion Developer Summit: AMD Graphics Core Next.

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SLIDE 6

Tahiti GPU Architecture: Compute Unit

Based on AFDS11 presentation: M Houston and M Mantor. (2011, June) Fusion Developer Summit: AMD Graphics Core Next.

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SLIDE 7

Simulation: Computation Flow

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SLIDE 8

Simulation: Update

PS solver is based on sequential implementation of R Stewart and W Bair, "Spiking neural network simulation: numerical integration with the Parker-Sochacki method," Journal of Computational Neuroscience, vol. 27, no. 1, pp. 115-133, August 2009.

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SLIDE 9

Simulation: Expand

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Simulation: Sort

Modified from T Harada and L Howes. (2011, Dec.) Heterogeneous Compute.[Online]. http://www.heterogeneouscompute.org/wordpress/wpcontent/uploads/2011/06/RadixSort.pdf Radix sort example: 1 bit radix. LSD sort.

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SLIDE 11

Simulation: Address

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SLIDE 12

Results: Verification and Testbench

A unit test for each kernel

A unified integration test with complete host-device verification

A variety of compilation modes

C++ preprocessor-driven

  • ptimizations

XML-driven search script for the best performing variant.

User Interface:

Perl script + XML

Microsoft VS

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SLIDE 13

Results: Performance

Network Size (neurons) Average Synapses per Neuron Average Events per Step Average Spikes per Step T

  • tal

Synapse Count (millions) GPU Time per Step, (ms) CPU Time per Step, (ms) Time Ratio

2,100,000 90 230,000 2,522 190 13.5 659 48 131,000 1,458 370,000 257 191 5.7 279 48 16,000 11,677 300,000 25 191 3.2 283 88

Size-connection scalability in multi-precision networks with per-WF precision allocation.

1000 iterations, 250 us step

Randomly-connected SNN with only AMPA synapses.

GPU: Radeon™ HD 7970, CPU: AMD Phenom™ II, 3.2 GHz (single thread)

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SLIDE 14

Simulator: Next Architecture

Out-of-order flow with event-based synchronization

Target-oriented synaptic matrix partitioning

Mixed hybrid and time-driven simulation flows

Variety of neuron models

STDP

Just-in-time spike-to- event expansion

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SLIDE 15

Conclusion

Object-oriented design

Out-of-order execution flows

STDP feature

Linux support

Application examples

User interface (possibly a library with extensions to PyNN)

APU support

Other: root-cause Newton-Raphson divergence, just-in-time spike-to-event expansion, sort radix scalability.

 Multi-precision scalable (neurons, connections, precision) SNN

parallel simulator.

 OpenCL, Tahiti architecture.  Fully verified with CPU original implementation.  Up to 90x faster compared to a single thread on CPU.

Future Work (in the order of importance)

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SLIDE 16

Selected Bibliography

R. Stewart and W. Bair, "Spiking neural network simulation: numerical integration with the Parker-Sochacki method," Journal of Computational Neuroscience, vol. 27, no. 1, pp. 115-33, Aug. 2009. E. M. Izhikevich, "Simple model of spiking neurons," Neural Networks, IEEE Transactions on, vol. 14, pp. 1569--1572, 2003. B Gaster, D R Kaeli, L Howes, and P Mistry, Heterogeneous Computing with OpenCL.: Morgan Kaufmann Pub, 2011. T Harada and L Howes. (2011, Dec.) “Introduction to GPU Radix Sort.” Heterogeneous Compute. [Online]. http://www.heterogeneouscompute.org/wordpress/wpcontent/uploads/2011/06/RadixSort.pdf M Houston and M Mantor. (2011, June) Fusion Developer Summit: AMD Graphics Core Next. [Online]. http://developer.amd.com/afds D Yudanov, M Shaaban, R Melton, and L Reznik, "GPU-based simulation of spiking neural networks with real-time performance & high accuracy," in The 2010 International Joint Conference on Neural Networks (IJCNN), 2010, pp. 1-8.

Q&A

Lee Howes, Dr. Wu-Chun Feng

Thanks to Code: http://code.google.com/p/neurosim