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© 2017, Amazon Web Services, Inc. or its Affiliates. All rights reserved.
Thomas Delteil, Applied Scientist @ AWS Deep Engine
APJCTech Summit 2018, Macau
Debugging MXNet Gluon
modelsAnd other performance tricks
© 2017, Amazon Web Services, Inc. or its Affiliates. All rights reserved.
Thomas Delteil, Applied Scientist @ AWS Deep Engine
APJCTech Summit 2018, Macau
Debugging MXNet Gluon models
And other performance tricks

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© 2017, Amazon Web Services, Inc. or its Affiliates. All rights reserved.
Remote debugging with PyCharm
Visualizing deep learning
Performance tricks and gotchas

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Apache History
• CMU project of PHD students in 2015 and the Distributed
Machine Learning Community (DMLC)
• 2017 => MXNet Gluon Imperative API is released
Tianqi Chen
UW
Mu Li
Amazon AI
Yutian Li
Stanford
Min Lin
MILA
Naiyan Wang
TuSimple
Minjie Wang
NYU CS
Tianjun Xiao
Tesla
Bing Xu
Apple AI
Chiyuan Zhang
Google Brain
Zheng Zhang
MSR Asia

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Imperative vs Symbolic computational graphs
Symbolic
define, compile, run
Imperative
define-by-run in the host language
Inception model

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Imperative > Symbolic
Debuggable
Fast to prototype
Hybridizable

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Interactive Debugging

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Shapes
Values
Gradients

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Youtube tutorial

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Visualizing Deep Learning

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Network Architecture

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MXNet native code (#1) print(net)

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MXNet native code (#2) mx.viz.plot_network(sym)

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MXNet native code (#3) mx.viz.print_summary(sym)

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Netron (online tool)

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MXBoard sw.add_graph(net)

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System performance

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GPU: gpu_monitor (github)

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CPU / RAM: > top i

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Training metrics

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MXBoard

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MXBoard Scalars

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MXBoard Images

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Console

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Performance
Tips and tricks

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130 samples/sec 1.25x 2.41x 2.46x 2.53x 3.84x
GPU utilization

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Environment
mxnet-mkl (32x)
vs
mxnet

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I/O Bound
→ GPU Starvation

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#1 Asynchronously pre-fetching data (low CPU) (1.25x)
DataLoader(num_workers=CPU_COUNT-3)
#2 Offline preprocessing (full CPU)

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GPU → CPU memcopy synchronization idling
#3 Smart synchronization calls (2.46x)
→ Small networks

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Copy to GPU
Forward/Backward
Metric
Copy to GPU
Forward/Backward
Metric
Copy to GPU
Forward/Backward
Metric
Copy to GPU
Forward/Backward
Metric
Copy to GPU
Copy to GPU

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Execution engine
Imperative → Symbolic (2.41x)
net.hybridize()

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Hyperparameters
Batchsize (2.56x)

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Optimizer
Performance:
Time to accuracy

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Mixed precision training
float32 → float16 (3.84x)
net.cast("float16")

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Profiling
profiler.set_state('run')
…
profiler.set_state('stop')

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Conclusion
- Use Gluon to debug and iterate quickly
- Hybridize and optimize for speed
- Know your model: Visualize performance

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Thank you!
Follow-up:
tdelteil@
Github.com/thomasdelteil
AWS Deep Engine, Vancouver