Turducken: Hierarchical Power Management for Mobile Devices Jacob Sorber, Nilanjan Banerjee, Mark...
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Transcript of Turducken: Hierarchical Power Management for Mobile Devices Jacob Sorber, Nilanjan Banerjee, Mark...
Turducken: Hierarchical Power
Management for Mobile Devices
Jacob Sorber, Nilanjan Banerjee,
Mark Corner, Sami Rollins
University of Massachusetts, Amherst
Presentation prepared by:
Kip Coonley
Paper appears in “Proceedings of the Third International Conference on Mobile Systems, Applications, and Services” (MobiSys 05), Seattle, WA, USA, June, 2005
Additional figures from www.cs.dartmouth.edu/~sorber/slides/mobisys2005slides.ppt
Key issue: Battery Lifetime vs. Mobility
Scenarios and photos care of Nilanjan Banerjee www.csce.uark.edu/~nilanb/
Scenario 2 Scenario 3
Key question: Which device to use?
laptop phoneMote
Scenario 1
40W
2W
0.04WSensor
PDA
Laptop
Simple computationand storage
Download Web Pages
Very complex computation
Send/RecvMail
Tasks requiringlarge memory or storage space
Pow
er
Need
s
Choosing the right device for the job
Wake-On-Wireless [Shih, et al]Low-power radio receives wakeup messages
Requires in-network support
Focus on when to wake up
Possible Solutions (Related Work)
WiFi Power Save Mode (PSM)
Local Availability of dataStaleness issue
Battery technology
Energy scavenging
Wireless optimizations [Anand, et al], Disk Spindown [Helmbold, et al], Multiple radios [Pering, et al], Multiple processor cores [Mayo & Ranganathan]
none provide orders-of-magnitude scaling of power
A New Approach: Turducken – 3 devices in 1
WiFi detector
Mica2 Mote
PDA
Laptop
Example: Mote checks for a network, PDA checks for mail server,Laptop remains asleep until user reads the mail
• Integrate multiple independent platforms
• Pass control between tiers
• Suspend unneeded tiers
The Idea: Hierarchical Power Management
Reducible Power – Power that can be eliminated
Reducible vs. Non-Reducible Power
Non-reducible Power – Required for computation
• LCD Screen, Wireless power, Caching
• Power supply, On-board oscillators, Memory, I/O buses, Voltage & Current regulation
• Time Synchronization
Can be completely performed by the mote
Lowest tier periodically synchronizes with remote time server
• Web Prefetching
More complicated application which requires at least PDA
Mote detects wireless networks
PDA periodically fetches updates to frequently accessed pages
Involves user interaction
Both incoming and outgoing updates
Laptop accesses mail via proxy on the PDA
3 Applications
• Laptop
• Laptop+Mote
• Laptop+PDA+Mote
3 Configurations
A Tiered Approach
PDALaptop MoteUSB RS-232
Wake
Note on Methodology: Time dilation used to extrapolate data
• Power Draw Comparisons of Turducken Tiers
• Wakeup Interval vs. Lifetime for Integrated Turducken System
• Availability of Wireless Networks and its impact on the Turducken System
3 Experiments
Laptop Laptop+Mote
Full Turducken
Power-By-Tier
Wake Synchronization Time of Device
Time Synchronization
Mote is the right device for the job
Laptop & PDA always suspended
Wake Synchronization Time of Device
Web Caching
5MB storage = 15 websites cached
For always-on operation, Turducken lasts up to 10 times longer
Waking every 6 minutes, Turducken lasts 3 times longer
Wake Synchronization Time of Device
Laptop wakes 2 min every hr, 4MB of mail stored
Due to laptop user input, overall system lifetimes much less
For waking every 6 minutes, Turducken lasts 1.5 times longer
Availability of Wireless Network(Web caching only, 12 minute wake interval preset)
Probability of WiFi
Lif
eti
me (
hou
rs)
With no network, mote prevents laptop from waking
Turducken performs well over a variety of connectivity patterns
Conclusions & Thoughts
• Turducken extends laptop lifetime up to 10x (Always-on)!
• Where Turducken Wins - Laptop on > 17 min/hr
• Hierachical Power Management & Reducible vs. Non-Reducible Power
• Sleep/Wake power costs – this work averages
• Device portability/weight integration of tiers
• Device reliability with integration of tiers
Turducken: Hierarchical Power
Management for Mobile Devices
Jacob Sorber, Nilanjan Banerjee,
Mark Corner, Sami Rollins
Paper appears in “Proceedings of the Third International Conference on Mobile Systems, Applications, and Services” (MobiSys 05), Seattle, WA, USA, June, 2005
One more experiment: Reachability of Wireless Network(Web caching only, 12 minute wake interval preset, always available)
Similar results to Availability of WiFi except…
Mote cannot access WiFi -only detect it - PDA must work more