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8/4/2019 Isca Needle a 0610
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Moving the NeedleComputer Architecture Research
in Academe and Industry
Bill DallyChief Scientist & Sr. VP of Research, NVIDIABell Professor of Engineering, Stanford University
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Outline
The Research Funnel
Most ideas fail
Those that succeed take 5-10 years
The Research FormulaConstraints
The Academic Advantage
The Industrial Advantage
StartupsBest practices
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Goal Positive Impact on a Product
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T
he Research Funnel
Applications
Technology
Concept
DevModel Eval Dev
insight
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Most ideas fail
The ideas that succeed take a long time
Concept
DevModel Eval Dev
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Most ideas fail
The ideas that succeed take a long time
Concept
DevModel Eval Dev
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Most ideas fail
So terminate the bad ones quickly
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Most ideas fail
So terminate the bad ones quickly
Be a terminator, not an advocate
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Dally, Micro-Optimization of Floating-Point Operations, ASPLOS, 1989, pp 283-289
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Most ideas fail
The ideas that succeed take a long time
Concept
DevModel Eval Dev
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The ideas that succeed take a long time
So aim research 5-10 years ahead ofcurrent practice
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Current Architecture Practice
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Aim Here
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Enable this point
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Timeline for some ideas
Idea Concept Published Product (T
Stream Processing 1995 1998 2006 11
Virtual Channels 1985 1990 1992 7
Equalized Signaling 1995 1996 2000 5
High-Radix Networks 2002 2005 2008 6
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The Performance Equation
ckfCPINITime v!
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The Research Formula
ROI! rewardriskv effort
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Reward
If you are wildly successful, whatdifference will it make?
ROI!reward
riskv effort
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Effort
Learn as much as possible with as littlework as possible
ROI!reward
riskv effort
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Effort
Do the minimum analysis andexperimentation necessary to make apoint
ROI!reward
riskv effort
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Real and Artificial Constraints
Real Constraints Artificial Constraints
Laws of physicsFuture semiconductor processes
Packaging and thermal limitsFuture applications
Existing ISAExisting OST
odays benchmarksExisting compilersInfrastructure
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Constraining Infrastructure
uArch
Idea
Other
uArch
ISA
Compiler
Benchmarks
Binaries
Simulator
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Constraining Infrastructure
uArch
Idea
Other
uArch
ISA
Compiler
Benchmarks
Binaries
Simulator
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Constraining Infrastructure
uArch
Idea
Other
uArch
ISA
Compiler
Benchmarks
Binaries
Simulator
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The contribution is insight
Not novelty
Not numbers
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Research is ahunt for insight
Need to get off the beatenpath to find new insights
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Road-Kill Research
uArch
Idea
Other
uArch
ISA
Compiler
Benchmarks
Binaries
Simulator
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Looking here for lost keys
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Lost keys here
Looking here
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The Academic Advantage
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The Academic Advantage
Freedom
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The Academic Advantage
Freedom from artificial constraints
Freedom to fail (take risks)
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Academic research matched for earlystages of the funnel
Concept
DevModel Eval Dev
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Example: ELM
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Example: ELM
Balfour et al., "An Energy-Efficient Processor Architecture for Embedded Systems"CAL, Jan. 2008, pp 29-32.
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ELM Infrastructure
uArch
Idea
Other
uArch
ISA
Compiler
Benchmarks
Binaries
Simulator
Changed for ELM
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The Industrial Advantage
Resources and Experience
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The Industrial Advantage
Resources to carry out detailed studies
Experience to address commercial
constraints
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The ideal partnership:
Academic research 5-10 years out,focused on industry problems
Transferinsightto industrial researchto refine into product
Concept
DevModel Eval Dev
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What transfers is insight
Not academic design
Not performance numbers
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What transfers is insight
And its transferred by people
Not papers
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Concept
Analysis
Simulation
Prototype
Refine Concept
Detailed Design
Academic
Industrial
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Example: Cray T3D and T3E
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J-Machine
MIT 1987-1992 3-D network
Global address space Fast messaging andsynchronization
Support for manymodels of computation
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Cray T3D
Started working with Cray in1989
Project started early 1990 First ship in mid 1992
From J-Machine Network Fast communication/sync Global address space
For reality Alpha processors MECL gate arrays Robust software stack
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Best Practices for Academics
Long-term perspective (5-10 years) Know your customer and their long-term issues Look at tomorrows applications, not yesterdays
Maximize reward, minimize effort Estimate maximum impact terminate Minimal analysis and experiment to make the point
Exploit your freedom
Dont be limited by exiting tools, benchmarks, ISAs, Carry result to impact Build relationships with industry
ROI! rewardriskv effort
uArchIdea
ther
ISA
Compiler
Benchmarks
Binaries
Simulator
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Best Practices for Industry
Leverage academic research Build partnerships Articulate long-term research issues Be open-minded
Minimize artificial constraints Carry concepts across the gap Open infrastructure
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A Partnership
Academe Industry
Filtered, De-risked Concepts
Future issuesInfrastructure
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The Startup Path
When you cant find an appropriateindustrial partner, make one.
STAC, Avici, Velio, SPI
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Concept
Analysis
Simulation
Prototype
Refine Concept
Detailed Design
Academic
Startup
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Startup Pros/Cons
Pros
Dont have to convinceexisting company to
change course (until exit)
Cons
Have to convince investors(repeatedly)
Have to build a whole company,not just a development team Finance, sales, marketing,
Limited resources Impatient capital
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Example: SPI
Date Event
Jan 2004 SPI Incorporated
Nov 2004 First round financing
April 2006 Tapeout Storm-1Oct 2006 First ship of Storm-1
2007 Software, software, software
2008 Customers in production
Sept 2009 Doors close
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Much easier to license technology toan existing company
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Starting a company to bring a newsemiconductor product to market costs$30M (to cash flow positive)
If its a programmable processor, its $70M
Investors want a 10x ROI
Need to see a $700M exit to justify a newprocessor company
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The future of computer architecture
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The future of computer architecture
NOW is an ideal time for research to move the needle Computers are drastically changing Pervasive parallelism
Energy limited Bandwidth constrained
Opportunity to set the MSB of future computers in thenext few years
Requires changing the whole stack Requires industry-academe partnership
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Energy-Efficient Architecture
Abstracting Locality
20mm
7pJ
50pJ 500pJ
2000pJ
2000pJ
P P P P
L1 L1 L1 L1Net
L2
Net
L3
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Solution involves many levels of the stack
Application
Algorithm
Prog. System
Compiler
ISA
uArch
Design
Circuits
Process
Too constrained toinnovate within one layer
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Industry
Academe
ROI!reward
riskv effort
uArch
Idea
Other
uArch
ISA
Compiler
Benchmarks
Binaries
Simulator
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Moving the Needle
Computer Architecture Research
in Academe and Industry
Bill DallyChief Scientist & Sr. VP of Research, NVIDIABell Professor of Engineering, Stanford University