Artificial Intelligence (AI), specifically deep learning, is revolutionizing industries, products, and core capabilities by delivering dramatically enhanced experiences. However, the deep neural networks of today are growing quickly in size and use too much memory, compute, and energy. Plus, to make AI truly ubiquitous, it needs to run on the end device within a tight power and thermal budget. One approach to address these issues is Bayesian deep learning. This presentation covers: • Why AI algorithms and hardware need to be energy efficient • How Bayesian deep learning is making neural networks more power efficient through model compression and quantization • How we are doing fundamental research on AI algorithms and hardware to maximize power efficiency

1. Accelerating algorithmic and
hardware advancements for
power efficient on-device AI
Qualcomm Technologies, Inc.
@qualcomm_techJuly 2018

2. 2
By 2025, the data center sector could
be using 20% of all available electricity
in the world1
A cloud provider used the equivalent
energy consumption of ~366,000 US
households in 20142
Bitcoin mining in 2017 used the same
energy as did all of Ireland3
Computers
are consuming
an increasing
amount of energy
1. Andrae, Anders (2017) Total Consumer Power
Consumption Forecast; 2. The Verge (2014); 3.The Guardian (2017)
Given the economic potential
of AI, these numbers will
only be increasing

3. 33
Will we have reached the capacity of the human brain?
Energy efficiency of a brain is 100x better than current hardware
Source: Welling
2025
Energyconsumption
1940 1950 1960 1970 1980 1990 2000 2010 2020 2030
1943: First NN (+/- N=10)
1988: NetTalk
(+/- N=20K)
2009: Hinton’s Deep
Belief Net (+/- N=10M)
2013: Google/Y!
(N=+/- 1B)
2025:
N = 100T = 1014
2017: Extremely large
neural networks (N =137B)
1012
1010
108
106
1014
104
102
100
Deep neural networks
are energy hungry
and growing fast
AI is being powered by the explosive
growth of deep neural networks

4. 44
Value created by AI must exceed the cost to run the service
Broad economic viability requires energy efficient AI
Economic feasibility per transaction may
require cost as low as a micro-dollar
(1/10,000th of a cent)
• Personalized advertisements and recommendations
• Smart security monitoring based on image and sound recognition
• Efficiency improvements for smart cities and factories

5. 5
The AI power and thermal ceiling
The challenge
of AI workloads
Very compute intensive
Complex concurrencies
Real-time
Always-on
Constrained
mobile environment
Must be thermally efficient
for sleek, ultra-light designs
Requires long battery
life for all-day use
Storage/memory
bandwidth limitations

6. 66
Soon, AI algorithms will be
measured by the amount
of intelligence they provide
per watt hour.

7. 77
Weight parameter
Activation node
Edges
Parts Objects
OutputPixels
Dog?
Cat?
Deep learning
The good
Convolutional
neural networks
(CNNs) have been
very successful
• Extract learnable features
with state-of-the art results
• Encode location invariance,
namely that the same object
may appear anywhere in
the image
• Share parameters, making
them “data efficient”
• Execute quickly on modern
hardware with parallel
processing

8. 88
Weight parameter
Activation node
Edges
Parts Objects
OutputPixels
Dog?
Cat?
Deep learning
The bad and the ugly
CNNs use too much
memory, compute,
and energy (today)
• CNNs do not encode
additional symmetries, such
as rotation invariance
(object may appear in any
orientation1)
• CNNs do not reliably
quantify the confidence in a
prediction
• CNNs are easy to fool by
changing the input only
slightly, such as adversarial
examples
1. Cohen & Welling 2016

9. 99
Edges
Parts Objects
OutputPixels
Dog?
Cat?
Bayesian deep-learning
addresses these challenges
Inspired by brain functionality, introducing noise
to neural networks is beneficial
Noise can be a
good thing for AI
Compression
and quantization
• Reduce complexity
of the neural network model
• Reduce bit-width of the
parameters and activations
• Save power and
improve efficiency
Introduce noise to weights Noise propagates to activations

10. 1010
Edges
Parts Objects
OutputPixels
Dog
Cat
w1
w2 (Y)
w2
w1 Initial weight values Apply Bayesian
deep-learning to
shrink the model
Compression
and quantization
• Quantize weights:
Use lower precision (bit-width)
• Prune activations:
Reduce number of activation
nodes

11. 1111
Edges
Parts Objects
OutputPixels
Introduce noise to parameters
Dog
Cat
w1
w2 (Y)
Prior P(W)—distribution before data (X)
w2
w1 Initial weight values Apply Bayesian
deep-learning to
shrink the model
Compression
and quantization
• Quantize weights:
Use lower precision (bit-width)
• Prune activations:
Reduce number of activation
nodes

12. 1212
Edges
Parts Objects
OutputPixels
Introduce noise to parameters
Add data (X)
Dog
Cat
w1
w2 (Y)
Prior P(W)—distribution before data (X)
w2
Posterior P(W| X,Y)—
distribution after data
w1 Initial weight values Apply Bayesian
deep-learning to
shrink the model
Compression
and quantization
• Quantize weights:
Use lower precision (bit-width)
• Prune activations:
Reduce number of activation
nodes

13. 1313
Edges
Parts Objects
OutputPixels
Introduce noise to parameters
Add data (X)
Dog
Cat
w1
w2
Prune activations
(similar method as
quantization)
X
Quantize weights
(or even remove)
(Y)
Prior P(W)—distribution before data (X)
w2
Posterior P(W| X,Y)—
distribution after data
w1 is pinned down
w2 is still highly uncertain
w1 Initial weight values Apply Bayesian
deep-learning to
shrink the model
Compression
and quantization
• Quantize weights:
Use lower precision (bit-width)
• Prune activations:
Reduce number of activation
nodes

14. 14
Bayesian deep learning provides broad benefits
A powerful tool to address a variety of deep learning challenges
Compression
and quantization
Quantize parameters and
activations, prune model
components
Regularization
and generalization
Avoid overfitting data; choose
the simplest model to explain
observations (Occam’s razor)
Confidence
estimation
Generate the confidence
intervals of the predictions
Privacy/adversarial
robustness
Avoid storing personal
information in parameters, be
less sensitive to adversarial
attacks

15. 1515
83%
84%
85%
86%
87%
88%
89%
90%
1 1.5 2 2.5 3 3.5
Top5Accuracy
Compression ratio
ResNet-18 on a large set of labeled images
Baseline Channel pruning SVD Bayesian pruning
Applying Bayesian deep learning to real use cases
Image classification
Zhang, Zou, He, & Sun 2015 (SVD);
He, Zhang, & Sun 2017 (channel pruning)
compression ratio while maintaining close to the same accuracy3X

16. 16
What does the
future look like
for AI hardware?
Distributed computing
architectures
AI acceleration
research

17. 1717
AI acceleration research
Balance AI acceleration capabilities across engines (CPU, GPU, DSP)
Focused on fundamentals to accelerate deep learning workloads at low power
Memory hierarchy
Optimize the memory hierarchy to reduce
the power consumption of data movement
while ensuring performance
Compute architecture
Optimize instruction type, parallelism,
and precision of the functional units
Utilization
Exploit sparsity to improve utilization and reduce power consumption

18. 18
Algorithmic
advancements
Neural network algorithm design
optimized for hardware
Optimization for space and
runtime efficiency
Efficient
hardware
Efficient architecture design
Selecting the right compute
engine for the right task
Software
tools
Software-accelerated
run-time for deep learning
Neural processing SDK for
model compression and
optimization
The approach
for making
power efficient
on-device AI
Focusing on the joint
design of algorithms and
hardware to achieve
high performance

19. 19
AI algorithms and hardware
need to be energy efficient
We are a leader in Bayesian
deep learning and its
applications to model
compression and quantization
We are doing fundamental
research on AI algorithms,
software, and hardware to
maximize power efficiency

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www.qualcomm.com & www.qualcomm.com/blog
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