1. Low Power
Keeps Getting Hotter
Barry Pangrle, Ph.D.
Solutions Architect
Mentor Graphics Corporation
Israel, May 4, 2010 © 2010 Mentor Graphics Corp.
www.mentor.com

2. The Next 25 Minutes…
• Purpose:
– Update Information on Power-Efficient Design
• Process:
– Background
– Trends Data
– Q&A
• Outcome:
– Better Understanding of:
• Where the Industry is Going
• How it Affects You
• How to Best Leverage the Design Process for Your Needs
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 2
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3. Designers Facing More
Green Requirements
Created and runs the Energy Star A global consortium dedicated to
Program in the U.S. among other developing and promoting energy
programs for controlling efficiency for data centers and business
environmental impact computing ecosystems
Companies displaying The Green Fan logo
Aims to reduce energy consumption in demonstrate that they are actively making
worldwide ICT networks by a factor of a positive contribution to reducing CO2
1000 emissions
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 3
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4. Power Impacts the Whole System
HLS
HLS
TLM
TLM Architectural Analysis
Architectural Analysis
Power-Aware Models
Power-Aware Models
System Level Verification
Verification
Design Power-Aware
Power-Aware
PCB Chip
Design Design
Package Test
Test
PCB Power-Aware
Power-Aware
PCB Design
Power Integrity
Power Integrity
Place & Route
Place & Route
Multi-Corner Multi-Mode
Multi-Corner Multi-Mode
“Platform power is as important as core silicon power.”
— Joe Macri, CTO, AMD
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 4
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5. Low-Power Requirement vs.
Power Trend
Requirement
Trend
3.5
3.0
2.5 Static Dynamic
(W)
2.0
1.5
1.0
0.5
0.0
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
SOC Consumer Portable Power Trend
Source: The International Technology Roadmap for Semiconductors (ITRS), 2008 Update
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 5
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6. Low-Power Requirement vs.
Power Trend
Requirement
14.0
12.0
10.0
Static Dynamic
8.0
(W)
6.0
4.0
2.0
0.0
2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
SOC Consumer Portable Power Trend
Source: The International Technology Roadmap for Semiconductors (ITRS), 2009
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 6
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7. Power Driven by Advanced
Technology Adoption
250nm 130nm 90nm 65nm 45nm
% of Total Silicon Demand Share
30% DVFS
power gating
multi-Vt
20%
clock gating
10%
0%
’95 ’96 ’97 ’98 ’99 ’00 ’01 ’02 ’03 ’04 ’05 ’06 ’07 ’08
Source: VLSI Research, Silicon Demand, July 2008
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 7
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8. Power Driven by Advanced
Technology Adoption
<=130nm 90nm 65nm 45 / 40nm
% of TSMC Total Wafer Revenues
70% of Wafer Revenues
60%
40%
30% of Wafer Revenues
20%
16% of Wafer Revenues
9+% of Wafer Revenues
0%
7
6
9
8
1Q 4
5
9
’0
’0
’0
’0
’0
’0
’0
1Q
4Q
1Q
3Q
1Q
1Q
Source: TSMC Quarterly Reports
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 8
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9. Power is *NOT* Scaling with
Technology
“In a decade, 11nm process
technology could deliver
devices with 16x more
transistors running 2.4x
faster than today's parts.
But those devices will only
use a 1/3 as much energy as
today's parts, leaving
engineers with a power
budget so pinched they may
be able to activate only 9%
of those transistors.”
–Mike Muller, CTO
http://pc.watch.impress.co.jp/docs/2004/0524/epf01.jpg ARM
http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=220900080
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 9
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10. Lower Threshold: Higher Leakage
Low Vt
90 nm Process
High Vt
10000
1000
nW
100
10
1
0 16 32 48 64 80 96 12 28 44 60 76 92 08 24 40 56 72 88 04 20 36 52 68 84 00 16 32 48 64 80 96 12 28
1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 4 4 4 5 5
Sorted Cell #
“Managing leakage power at 90 nm and below”
below”
Barry Pangrle and Shekhar Kapoor , EEdesign.com, Nov 05, 2004
EEdesign.com,
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 10
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11. Leakage vs. Delay Tradeoff
1000
90 nm
Transistors
100
Ioff (nA/mm)
10
Ioffn
1
Ioffp
0.1
0.01
0.001
5 10 15 20 25 30
Gate Delay (pS)
“Managing leakage power at 90 nm and below” , Pangrle and Kapoor , EEdesign.com, Nov 05, 2004
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 11
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12. Leakage Exceeds Dynamic Power
“DC power has
exceeded AC power
for the first time.”
– John Y. Chen
VP of Technology and Foundry Ops
NVIDIA
http://www.semiconductor.net/article/438968-
http://www.scu.edu/engineering/ee/images/John_Chen_1.jpg
Nvidia_s_Chen_Calls_for_Zero_Via_Defects.php
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 12
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13. Body Bias has Diminishing Impact
0.15
G
130nm
0.1 210 mV
S D
90nm
∆VTH (V)
0.05 95 mV
B
0 55 mV
65nm
-0.05
-0.1
-0.5 Reverse 0 Forward 0.5
VBS (V)
“Low Power Design Essentials”, Jan Rabaey, 2009
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 13
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14. When Power Doesn’t Scale …
Power Density Clock Frequency
1000 Rocket Nozzle 100000
Inflection Point Inflection Point ~30GHz
Nuclear Reactor 10000
100 P4D
C2D P4
P4 C2DCi7
Watts/cm2
Pentium® III Ci7 Pentium® III 1000
Pentium® II P4D
MHz
MHz
Hot Plate Pentium® II
10
Pentium® Pro Pentium® Pro 100
Pentium® Pentium®
i486 i486
i386 i386
1 10
1µ 0.5µ 0.25µ 0.13µ 65nm ’87 ’92
’97 ’02 ’07 ’10
“The numbers I would cite would be by 2010: 30GHz, 10billion
transistors, and 1 tera-instruction per second.”
--Pat Gelsinger, CTO, Intel April 9, 2002
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 14
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15. Power Efficiency is the Main Goal
“Achieving very high
operating frequencies is no
longer the prime target for
new microprocessors.
Instead, the goal has shifted
to delivering higher
performance combined with
lower power. “Power
efficiency” is the main
scaling goal for chips used
both in small hand held
devices and in large data
http://www.scu.edu/engineering/ee/images/John_Chen_1.jpg
centers.”
http://www.intel.com/pressroom/kits/bios/mbohr.htm
–Mark T. Bohr, Intel Senior Fellow
Intel
http://blogs.intel.com/idf/2010/04/moores_law_after_32nm.php
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 15
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16. Leading Processor Power Budgets
I/O
Mem I/O
Clock Clock
MPU1 Mem MPU2
Logic Logic
I/O Clock Clock
ASP1 ASP2 Logic
Mem Mem
Logic I/O
• Power budgets of leading general purpose (MPU) and
special purpose (ASP) processors
Jan Rabaey, “Low Power Design Essentials”, various references
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 16
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17. Clocks
Power
• Increases as skew and jitter
decrease
• Insertion delays increase,
longer buffer chains, power
increases clk
Timing
• Use skew to improve timing
IR-Drop Power
• Increases as skew decreases
“0-skew” clk
• Lower drop-> lower margin->
lower voltage-> less power
• Reliability & noise Power
• During test can cause good
die to fail “∆-skew” clk
∆ ∆
Packaging
• Ldi/dt, IR drop, thermal
considerations
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 17
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18. Low-Power Design and Multi-Core
• Cores per die
continues to
increase
April 2003 • Each core is a
Single-Core 130nm April 2005 candidate for its own
Dual-Core 90nm power island
• As cores increase so
do operating modes
• Multi-Core chips are
September 2007 June 2009 impractical w/o low-
Quad-Core 65nm Hexa-Core 45nm power design
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 18
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19. Low-Power Design Requires MCMM
Cell Phone Chip Example
Wally Rhines' DesignCon 2009 Keynote Address:
“Common Wisdom Versus Reality in the
More than 21 mode/corner scenarios Electronics Industry”, February 3, 2009
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 19
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20. Concurrent Power and Timing Closure
for Multi-Voltage Designs
Core: Island1:
1.2v-1.8v
Island1:
0.9v-1.5v
0.9v-1.5v
ON/OFF
ON/OFF
Island2:
Island2:
0.9v-1.5v
0.9v-1.5v
1.2v-1.8v
1.2v-1.8v
Complexity Grows
as More Domains
are Added
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 20
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21. EDA Waves
• Tools and
methodologies are
always chasing the
available capabilities of
the existing
technologies
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 21
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22. The Next Big Wave
• Increased design
complexity due to
the shear number of
available gates
demands higher-
level tools
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 22
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23. Why Optimize Power at the
Architecture?
Power Optimization Potential
Architectural
RTL Synthesis
Gate
Layout
0% 20% 40% 60% 80% 100%
Source: LSI Logic
Design and Optimization in the ESL Domain
has the Biggest Impact on Power
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 23
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24. Evolving Role of Design Phases in
Overall System Power Minimization
ESL
(Behavioral) ESL
(Behavioral) ESL
20% (Behavioral) ESL
ESL 30%
40% (Behavioral)
(Architectural) 50%
ESL
20%
(Architectural)
RTL 10% 20% ESL
RTL 10% (Architectural)
ESL
30%
(Architectural)
30%
Physical 50% RTL 10%
Physical 40%
RTL 10%
Physical 20%
Physical 10%
2009 2011 2013 2015
Source: The International Technology Roadmap for Semiconductors (ITRS), 2009: Design
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 24
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25. Low-Power Architectural Exploration
“I want high-level tools to help me do design exploration.”
Power
Power tools for architecture exploration
Rapid evaluation of the power and perf
impact of architecture tradeoffs
End-of-flow tools are not sufficient
Low-power X
Storage arrays, interconnect, etc…
Custom design for power, not perf
Optimized Vdd, Vt
Bill Dally Bill Dally‘s 46th DAC Keynote Address: “The End of Denial
Sr. VP Research, Nvidia Architecture and the Rise of Throughput Computing”, July 29, 2009
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 25
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26. Architectural Impact on Low-Power
Transmitter Min. Freq. to Area Average
Design Achieve Req. Rate (mm2) Power
(IFFT Block) (mW)
3.99
Comb ( 48 bfly4s ) 1.0 MHz 4.91 3.99
Piped ( 48 bfly4s ) 1.0 MHz 5.25 4.92
Folded ( 16 bfly4s ) 1.0 MHz 3.97 7.27 ~8.6x
Folded ( 8 bfly4s ) 1.5 MHz 3.69 10.90
Folded ( 4 bfly4s ) 3.0 MHz 2.45 14.40
Folded ( 2 bfly4s ) 6.0 MHz 1.84 21.10 34.6
Folded ( 1 bfly4 ) 12.0 MHz 1.52 34.60
8.6x power variation resulted from architecture tradeoffs
Source: “802.11a Transmitter: A case Study in Microarchitectural
Exploration”, N. Dave et. al., Proceedings of MEMOCODE 2006
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 26
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27. TSMC Sees the Importance of
This Too
ESL/HLS
SiP
½ Node
Design Challenges
DFM AF
Stat Tim’g
DFM
Pwr Mgmt
Pwr CF
SI CF
Hier Flow
Tim’g CF
RF 5.0 RF 6.0 RF 7.0 RF 8.0 RF 9.0 RF 10.0 RF 11.0
2004 2005 2006 2007 2008 2009 2010
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 27
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28. Example: Power Down / Up
Sequence
Power down
sequence correctly
executed for
isolation, retention &
power
Corruption of
internal nets during
power down
Output values
restored at power up
Outputs remain at
Output values saved isolated value
during retention during power down
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 28
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29. Low-power Test Considerations
Reduce Power During Test Test for Low-Power Designs
Design partitioning Power information
— Test in multiple sessions — UPF/P1801
— Untested cores use low
power Test in presence of low-
power features
Low-power ATPG — DRC
— Reduce switching during: — ATPG
– Load
– Capture Test of low-power features
– Unload — Power gating control logic
— Power metrics reporting — Retention cells
— Constant flow compactor — Isolation cells
— ATPG gater control — Level shifters
29
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 29
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30. Packaging Impacts Power
• “These days about half
of the dissipation in
microprocessors comes
from communication
with external memory
chips. If these chips are
stacked together in 3D,
communication energy
cost might drop to a
tenth.”
– Bernard Meyerson, CTO of the
Systems & Technology Group,
IBM
http://techon.nikkeibp.co.jp/article/HONSHI/20090527/170863/
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 30
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31. Power Issues Extend to the Board
• ICs have a power problem
Trends:
– Lower & Multiple voltages/IC
– Higher currents
– Lower voltage supply
tolerances
• PCB power distribution
networks are more complex
– Multiple PDNs on single PCB
– Requires “jigsaw” of split
power / ground planes
– Over-conservative design
increases cost
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 31
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32. Low-Power Flow Solution
Design Verification
TLM-Based
TLM-Based RTL & Gates
RTL & Gates
ESL
ESL
Power-Aware
IEEE Std 1801™-2009
Power-Aware
IEEE Std 1801™-2009
Power-Aware Models
Power-Aware Models
HLS
HLS Formal Checks
Formal Checks
Architectural
Architectural
Trade-Off Analysis Power Rule Checking
Power Rule Checking
Trade-Off Analysis
Test
Test Clock Crossings
Clock Crossings
Power-Aware Test
Power-Aware Test
Multiple Domain issues
Multiple Domain Issues
Issues
issues
Low-Power Test
Low-Power Test
Place & Route LVS // DRC
LVS DRC
Place & Route
Layout-Level
Layout-Level
Multi-Corner Multi-Mode
Multi-Corner Multi-
Multi- Multi-Mode Power-Aware Checks
Power-Aware Checks
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 32
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33. Summary
• Rescued by New Process Technology?
– Not Likely Soon
– Probably Will Get Worse Before it Gets Better
• Standardized Formats
– Significant Aid to Design & Verification Flows
• Power is a System-Wide Optimization
• Biggest Bang for the Buck is in Front-End
Design
Israel, May 4, 2010 © 2010 Mentor Graphics Corp. 33
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34. Thank You!
Israel, May 4, 2010 © 2010 Mentor Graphics Corp.
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