nokia research & ucb - chesschess.eecs.berkeley.edu/pubs/890/pemp feb 2012 ucb dreams.pdfnokia...
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Nokia Research & UCBBerkeley, Jan 31 2012
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Per LjungPerformance Efficient Mobile PlatformsNokia Research, [email protected]
•Background• Nokia• Nokia Research• Nokia Research Berkeley
•Opportunities for Energy Savings• energy sources & sinks• what can we expect
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Nokiachallenger mindset
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•High-end Windows Phone• 3rd ecosystem• first devices just announced ... lots more coming
• Connect the Next Billion• developing world• similar capabilities, different price points
• Future Disruptions• energy efficiency, big data, form factors, ...
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Nokiawhat is going on?
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•Telecom industry• interesting times with M&A, exits, fails• Q3’2011 mobile > PC • 4.6B handsets ~ global population
•Largest mobile manufacturer• shipped +1B mobile devices • 450M/year = 100M high-end + 350M low-end• typical product 10M• 130k employees
+1M every day
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Nokiawhat is going on?
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• OS• Symbian is end-of-lifed
• ... expect to ship another +100M
• Meego is dead• linux is dead, long live linux• ... Qt/linux on $25 Raspberry Pi using a BCM chipset
• Windows• just announced first phones ... lots more coming• working with W8, WP, MSR
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NRCprototypes, patents, publications, tech transfer
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•Nokia Research• 25th anniversary• 11 labs worldwide ~400 hc• NRC NA, 100 hc
• Palo Alto• Cambridge• Berkeley, ~25 hc & growing
• Radio• Performance Efficient Mobile Platforms
•Some recent successes• BTLE, NFC, WebCL• indoor positioning, indoor maps• computational photography• CityScene augmented reality• Sesame Street virtual reality• MirrorLink automotive• XXX tech transfer to 5k hc• 50% of IPR
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NRC Berkeleyperformance efficient mobile platforms
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•Projects in Energy Efficiency• a CTO-level “Future Disruption”
• +50 hc• prototypes
• demonstrate ULP• low power radios/displays/cpus• linux kernel mods
• enable always-on apps
•UCB• collaboration & funding with Parlab, BWRC, LoCal
• Parlab Next “mobile” + “energy”• grants to researchers• recruiting• internships
50-3000mW, 5Wh+1 day
5-100mW, 1Wh+10 days
1-100mW, 5Wh+1 year
NRC BerkeleyNokia Confidential
Opportunities for Energy Savings in Mobile Devices
•Battery•Display •Communication•Computation•User
Per LjungPerformance Efficient Mobile PlatformsNokia [email protected]
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pJ/op and nJ/bit
NRC BerkeleyNokia Confidential
Mobile Energy Efficiency
• battery• 5Wh
• display• 0.5W → 10h
• computation• 1GHz, 1000 pJ/op, 1W → 5h
• communication• 1 Mbps, 1000 nJ/bit, 1W → 5h
Yesterday: Race to Haltmin comp timemin comm timemin display time
Today: background smart-phone apps(email, voip, social, streaming, gps, ...)
are battery killers
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how much functionality?
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handsets?
handsets?
Mobile Energy Efficiency
• Apple & Samsung leaders• best case 2x better energy efficiency
• WP7 vs iphone4• n900 vs iphone3gs
• EU FP7 (EARTH)• demo 2x in 2 years • Ericsson, Alcatel, NXP, Docomo, ...• €10M• www.ict-earth.eu
• Bell Labs GreenTouch• roadmap 1000x by 2015• China mobile, AT&T, Broadcom, Huawei, Samsung, ...• www.greentouch.org
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SW not HW
free money, low ambition
ambitious
players & directions
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Mobile Energy Efficiency
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Shannon Limit
Rx ~ 10-12 nJ/bit(Received energy per
bit for single link in limit of
zero spectral efficiency)Tx
100 nJ/bit
Tx102 nJ/bit
Grid Power106 nJ/bit
Ideal Small CellsRadius ~ 50 m
Ideal Macro CellsRadius ~ 500 mSimulation Result
Opportunity~104 path losses
Opportunity~10 MIMO~10 Ant. Gain & Improved Rx
Opportunity~102 High BW
6HO(:P(5,#"&>'5(?M,
:HO(:P(,-2-'N-(?M,
TH
10-4 nJ/bitTx
10-2 nJ/bit
Opportunity~10 MIMO~10 Ant. Gain &Improved Rx
Residual Losses~108
Tx105 nJ/bit
Actual Macro CellsRadius ~ 500 m
Opportunity~10 Efficient PAs, low power electronics, passive cooling, etc.
Other~ 10 margin for QoS, overheads, nonidealities, etc.
Shannon Limit
•Q41-(;'**-,-"2-(RAS(),;-,&()*(>#1"'54;-T(U-5M--"(5,#"&>'55-;(
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circuits, transport, coding, architecture, protocols
1E17 mobile inefficiency
asymmetric TX 1W UE vs.120W BS
use small cells
thermal noise boundsactually interference limited
Green Touch 1000x/5 years
NRC BerkeleyNokia Confidential
Mobile Energy Efficiency
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• handsets• ~80% time stationary• use cheapest radio
•500x cheaper display• bi-static, no backlight
•1000x cheaper radio• ANT, ZigBee, BTLE ... not 3G/4G/wifi• tiny cells ... exploit your laptop• cheap & frequent data notifications
•100x cheaper processor• streaming/stack ... not RISC• embedded, not generic linux
2 nJ/bit vs 2 uJ/bitavailable today
10 pJ/op vs 1000 pJ/opavailable today
1 mW vs 500 mWavailable today
enable tomorrow’s cloud/streaming apps
general case: mobile
special case: home, office
100x doable now?
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Battery life
• typical handset• 32g, 13cc, 5.5Wh = 17kJ • +5h charging @ max 1W• 20mW static power = 10 days standby• 150mW notifications = 1.3 day standby• “typical usage” 5kJ active +12kJ standby = 1 battery charge
• iPad2• 25Wh = 90kJ• Apple: 10h use = avg 2.5W• MacWorld: video play 8.4h = 3W
•Kindle3• 6.5Wh = 23kJ• Amazon: “30days @ 30m/day” = 60h = avg 110mW• B&N: 56h @ 1page/min
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how long between recharges?
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Energy sources
• battery• 4% cagr• typical +5h charging time @ max 1W• super-cap like charging rates with nano-
structure anode & cathode• 30m charging @ 15A instead of 5h
• energy density • 7x to Al-air, 12x to dynamite
0.01
0.1
1
10
100
1,000
10 100 1,000 10,000
10h 1h 0.1h
36s
3.6s
0.36s
36ms
Libattery
supercaps
Al electrolyticcaps
Spec
ific
ener
gy W
h/kg
Specific power W/kg
combustionengine
lead
aci
d
redox N
iCd
fuel cell
Al air
Zn a
ir
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limited opportunity
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Energy sources
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2004: Nokia’s Fuel Cell operated Bluetooth Headset
fuel cell
• high energy, low power• need accumulator
NRC BerkeleyNokia Confidential
Energy sources
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1997: Nokia 1611
2011: Nokia Liidokki
• best 320mW• sun 100mW/cm2
• typical area 20 cm2
• typical efficiency 16%, world record 42%
• typical ZTE S316• 17h @ 120mW = 2.1Wh full charge• 2.5h charge = 0.3Wh = 24h @ 12mW standby + 2m @ 390mW voice
solar
NRC BerkeleyNokia Confidential
Energy sources
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wireless charging
• effective within 3 coil diameters• lots of proximity chargers coming
NRC BerkeleyNokia Confidential
Display
• LCD+, AMOLED, E-Ink, Pixel Qi, Mirasol, ...
• mobile LCD• 300-800mW (backlighting on)• 30mW (graphics driver)• assume 2.5h/day
• LCD 0.5*2.5 = 1.25 Wh (23% of 5.5 Wh battery)• E-Ink 0.1*2.5 = 0.25 Wh (5%)• Mirasol 0.03 = 0.1 Wh (1%)
• tablet LCD• +4x backlighting power
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bistatic, transflectance, color, video, ...
NRC BerkeleyNokia Confidential
Communication• 2G
• ~20mW standby, 0.6W, 9h talktime
• 3G• ~20mW standby, 1W, 5.5h talktime• massive overhead from t1, t2 timers• +1s setup latency• “worst case” sending 1 byte is 0.6W*2s=1.2J
• “best case” sustained 100,000x more efficient• newer low power idle modes, CPC, DTX/DRX, FastDormancy• proprietary QuickRelease not allowed by some operators
• notifications, keep-alive signals• email + skype = 150mW notifications = 1.3 day standby• want to aggregate/reduce
• wifi• 100mW standby, 1W active
• LTE• 100mW standby, +1W active• ~0s latency, min overhead
t1DCH
PCH
t2FACH
IDLE
data
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Nokia Energy Profiler
voice, data, notifications
NRC BerkeleyNokia Confidential
Communication
• 1000x cheaper radio • ANT, Zigbee, BTLE instead of 2G/3G/wifi (2 nJ/bit vs 2uJ/bit)• tiny cells, connect to your laptop• AT&T femto is 10x worse (t1=4m)
• parallel voice+data • share channel, 0.6x energy
• striping data • avoids TCP slow restarts, 0.6x energy
• enqueue & aggregate notifications • avoid T1 overhead, 0.25x energy
• burst (not streaming)• enable sleep, 0.6x energy
• protocols • E(N*data) << N*E(data)
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Pow
er [W
]
Ener
gy [J
]
time [s]
t1
t2
Pow
er [W
]
Ener
gy [J
]
time [s]
t1
t2
aggregated
voice, data, notifications
NRC BerkeleyNokia Confidential
Computation
•optimize performance != optimize energy• hw specialization• typical risc +500 pJ/op• re-compute vs re-use
•many-cores, conservation cores• Denard power scaling dead• low activation = dark silicon• offload cpu to conservation cores
• Amdahl’s law for energy• assume 95% runs in 0 energy → max 20x improvement
180-250nm
50nm
16 mm
0.3 pJ/op
1.7 pJ
17 pJ
400 pJ
ALU
1mm
10mm
off-chip
reg.readram.read
0.6 pJ3 pJ
45-90nm
1,000,000
1
10
100
1000
10,000
100,000
1998-2002 ISSCC designs
pJ/
op
cpu
dsp
asic
task energy relative
comp
on-chip comm
off-chip comm
off-handset comm
0.3 pJ 1
3 pJ 10
400 pJ 1,000
8 uJ 25,000,000
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applications & processors
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Computation
•hibernation• min static power = normally off, modem on• wake-on-event (voice, sms, data, local info, ...)• meego: 20s suspend, 3s resume
• secondary low-power processor• context recognition (radio, location, activities, gestures)• e.g. TI Omap5
•offload• proxy in remote cloud / local femto• e.g. vnc “pc-over-ip” 1W wifi, Onlive gaming 100ms latency• wake-by-cloud (filter data)
•100x cheaper processor• streaming or stack (10pJ/op), not risc (1000 pJ/op)
•native vs web• E(native) ≤ E(javascript), E(ajax) < E(html)• comm protocol dominates -- avoid slow servers• web-based phone
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OffCallphone is normally off, wake on event
N900 Existing Proposed
standby
typical
0.04W marketing = 4 days0.16W w/ notifications = 1.3 days
0W marketing = ∞ days0.005W w/ notifications = 32x
night 8h events=0, freq=Infcommute 1h events=0, freq=Infwork 9h events=27, freq=20mcommute 1h events=1, freq=60mevening 5h events=10, freq=30m
active 2.4h=5.1kJstandby 21.6h=12.4kJtotal 24h=17.5kJ
1 day battery
hibernate if no event within 4mactive 2.4h=5.1kJstandby 21.6h=1.6kJtotal 24h=6.7kJ
2.6x battery life
•OffCall = NoBoot + events•Meltemi liason, sw, device
P
tnight commute commutework evening
hibernate
event
applications & processors
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NRC BerkeleyNokia Confidential
Computation
10 8 10 6 10 4 10 2 100 102104
105
106
107
108
109
1010
1011
1012
1000
pJ/in
str10
0pJ/i
nstr
10pJ
/instr
1pJ/i
nstr
0.1pJ
/instr
Watt
IPS
NXP Coolflux (65nm)TI MSP430 (65nm)Atmel AT89LPAtmel AVRPCH7970HTC 80C51Xemics XE88LCOEM6607Intel Core Duo Yonah (65nm)Intel Atom (45nm)Arm Cortex A9 (65nm)Arm Cortex M0 (90nm)MIPS 1074K (40nm)Qualcom SnapDragon (65nm)Xmos XS1 G4 (65nm)SPI SP16HP (130nm)Tilera Gx100 (40nm)GreenArrays GA144 (180nm)PicoChip PC203 10 (65nm)UCB nems adderUCB saptlSkansky adderUMich SubliminalUMich PhoenixStanford ELM (90nm)
4G
3G low power
risc
many-core
academic
1/N-coreregister/stack/streaming
sync/asyncsub/near/super threshold
cmos/nems
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+100x improvement?
NRC BerkeleyNokia Confidential
User
•usage feedback• power, energy• apps, trends• frequency → priority
• location• local offload• find historical cheap down/uploads, defer expensive• sync with cheapest radio• sync when charging
•activity• driving, commuting, meetings, sleeping• wake-by-cloud (e.g. Mom calling at 2am)• “essentials mode” 2G voice-only
general case: mobilespecial case: home, office
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flexible QoS with context recognition
NRC BerkeleyNokia Confidential
P&E summary
•Battery• 1-2x energy content• 10x faster charging
•Display • 4x eliminate backlight• 500x bi-static
•Communication• 4x aggregate notifications• 1000x tiny cells
•Computation• 3x hibernation• 100x processor
•User• 1-2x context
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some interesting opportunities
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UCB projects
•ULP processor• GreenArrays
• microforth, 18b, 64 word instructions, 16 word stack• 144 cores @ 750MHz = 100 GOPs• async, 25uW-625mW, 7pJ/op
• 2-day training, course/project?• hw-like schematic design, compiler possible?• move 180nm to <45nm with BWRC?• apps for networking, audio, UI, SDR, location-aware
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wishlist
•offloading• architecture for local/remote/cloud• re-factored box
• low-energy proxy• aggregate/enque, scheduling• filtering for wake-by-cloud
•mote-like• ULP for voice, notifications, sensors
• immersive UI• ultrasonic gesture recognition• uW transducer, mW algorithms?
NRC BerkeleyNokia Confidential
ThanksQuestions?
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Sound interesting?We are looking for PhDs and interns