1. Progress Report
2012/11/28

2. Computation Offloading
Mobile devices have limited energy and computing resources.
Offloading some workloads to remote servers leads to:
Power-saving.
Performance improving.
Shorter execution time.
Better results.

3. Computation Offloading(Cont.)
Offloading granularity:
Process level
Process migration.
Function/Method level
Target
Android apps.
Activity + Service

4. Applicable Image processing Audio processing Text processing
object recognition, OCR, face detection, barcode analysis
Audio processing
speech recognition
Text processing
machine translation
Artificial intelligence for games
Chess
3D rendering
3D home interior design
Security
taint analysis and virus scans

5. Related Works Cyber foraging Scavenger(‘09) CloneCloud(‘10) MAUI(’10)
a pervasive computing technique where resource poor, mobile devices offload some of their heavy work to stronger surrogate machines in the vicinity.
Several studies since ‘01.
Scavenger(‘09)
CloneCloud(‘10)
MAUI(’10)

6. Related Works(Cont.)
Most of the existing works focus more on power than performance.
The most important element is the network speed, then the computation ability of server.
Recent studies focus on “how to make offloading decisions”.
Formulate into a 0-1 ILP problem.

7. Our Idea
Instead of studying offloading policies, we aim at the effects caused by offloading.
After offloading, a computation-intensive process becomes I/O-intensive.
Does this phenomenon affects scheduler?
Does this phenomenon affects DVFS?
Does this phenomenon affects cache/memory?
…etc.

8. Our Idea(Cont.) Identify the influence of property change.
Computation-intensive => I/O-intensive.
Understand Android's strategies for thread scheduling, thread allocation, thread migration, DVFS, and DPM.

9. Thread Scheduler Completely Fair Scheduler(CFS)
Since Linux
/kernel/sched.c
Maintain balance (fairness) in providing processor time to tasks.
Brain Fuck Scheduler(BFS)
…still studying.

10. Cuckoo
A framework that helps developers to offload computation to the server.
Offloading decisions are made by Cuckoo framework.
Offload if the remote resource is reachable.