Understanding Energy Efficiency of Android Apps

(and how to Improve it)

Aditya Kulkarni

Apps are to blame the most for bad battery life• Bad coding patterns

cause power bugs• Specific behaviors of the

Android Platform• App inter-dependencies!• Special Attention must

be paid to optimize for power!

Users Hate “Power Bugs”

Energy Consumption of An Android Phone

Understanding Power Bugs

Screen• color matters!– esp on OLED screens– darker the color, lesser

the consumption• brightness levels have

more impact– refer to -

http://stackoverflow.com/questions/5032588/cant-apply-system-screen-brightness-programmatically-in-android

Screen• programmatically

reduce brightness if its suits your app/activity

• Use “night mode” for reading Apps

• Think about your color scheme

CPU• wakelocks are your friend,

but your users worst nightmare!

• use them only if really needed and ensure they are removed as soon as possible

• Use ‘android:keepScreenOn’ property in your manifest instead of doing it programmatically

CPU• if possible, spread out your

computationally intensive job

• gpu typically consumes more power than cpu– avoid floating point math

where possible• use algorithms that

consume less CPU cycle– O(n log n) vs O(n 2)

algorithms

Wireless Radios• 3G/4G LTE have tail

states and warm-up times

• Power States are controlled by the Carrier

• Batching, state checks are your friend!

GPS and Location Services• GPS is fairly heavy• Getting a location fix is far

more expensive than maintaining a fix

• Registering for notifications can have cascading effects

• Use Play Services Location APIs

Best Practices(or how to avoid the dreaded battery drain)

Common Power Bugs 1. Not Sleeping Properly

Common Power Bugs 2. Un-necessary Animations

Common Power Bugs 3. Updating the Screen

Common Power Bugs 4. Handling Display-Off

Common Power Bugs 5. Waking up to notifications

Use A Power Profiler Like Little Eye

Thank Youwww.littleeye.co

aditya@littleeye.co