1. Advanced Computer Systems
Karthik Dantu and Steve Ko

2. Administrivia Classroom change: Davis 338A
Please register on Piazza – announcements on Piazza from now on
Homework: clone AOSP repo
Bring your laptop on Friday
Project groups
Grouping – best effort
Projects : New ideas

3. Resource Accounting in Android
Build a kernel module that records resource usage – CPU, memory, sensors
Correlate shared resource usage with process
Module checks with the scheduler on which process is currently active
Assigns currently used resources to that process
Information available via the /proc process folder
Classify processes into active, moderate, and light based on usage
Study how to account for asynchronous resources
Members: Manish, Divya, Sharath

4. Crowd-sourced Wifi Mapping
Create a wifi-based indoor localization system
Modify wifi driver to put it into monitor mode
Use inertial sensors + wifi signal to locate a person as well as improve the wifi map
Data collection on PhoneLab
Design algorithm to opportunistically improve wifi-map by sampling users at locations where map is sparse
Team: Tom, Dipti, Aviral

5. Battery Simulator in Android Emulator
Build a battery simulator to model energy usage in the Android emulator
Modeling/measurement of energy usage of components of a phone
Modify emulator to incorporate energy simulation
Design energy emulator such that energy numbers can be provided at run-time
Hardware-in-the-loop emulation?
Members: Anudipa, Harsha, Harish

6. Record/Replay System for Android
Instrument Dalvik such that it records the interactions it has with lower layers of framework
Have a replay mode where one can replay a previous app execution
Run-time adaption of recorded information?
Members: Taeyeon, Aveek, Satyaditya

7. End-end Connectivity on Phones
Use netfilter to inspect end-end connection variation during switch from Wifi to 3G
TCP window size
SACK and other options
Suspend connection monitoring during transitions?
Distinguish between congestion due to a narrow pipe, and loss due to transition
Improve performance by being locally aware of the transition without modification to server
Team: Shiqin, Carl, Varun

8. Filesystem Comparison
Compare performance of various filesystems (ext4, reiserfs, jffs3) on Android platform
Make the root filesystem using various journaling filesystems
See how well each one does on flash
Members: Sharath Chandrashekhara, Pratik, Chun

9. Latency Measurement Mechanism
Implement a latency measurement module in the kernel
Take request/response cues from other kernel modules, and compute delay
Also take cues from device drivers
Verify on desktop system by writing a dummy device with known delays
Use latency manager to measure app switch delay
Team: Kai, Ruijie, Peng

10. Concurrency vs Duty Cycling of Shared Resources
Build a kernel module that manages shared resources to accommodate energy management policies, and concurrent requests
Disable wakelock usage by userspace
Allow use of shared resources only by requesting a schedule (once, repeat every)
Take the GCD of all app schedules as the duty cycle period
Demonstrate cases where this policy is better and worse
Team: Yin, Feng, Chirag

11. Information Leakage Due to App Permission Model
Apps use user permissions from classic Unix
Study and understand how resource sharing occurs in this model
Study potential ways to leak information across apps unintentionally in this model
Implement a service that actively detects such leaks at run-time
Members: Yan, Ravikanth, Sirak