1. Delivering great performance and battery life
11/30/2018 2:19 PM
HW-459T
Delivering great performance and battery life
Sharif Farag
Principal Lead Program Manager
Jason Hendrickson
Senior Program Manager
Microsoft Corporation
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. Agenda Expanding range of PC capabilities
Delivering great experiences across PC hardware
You’ll leave with an understanding of
Why Metro style apps are a great start for performance and power
How to take advantage of Windows 8 features for optimal performance and power
Tips for delivering a great experience across a broad range of hardware

3. Windows 8 has been designed to enable new experiences with great performance and energy efficiency.

4. Expanding range of PC
capabilities

5. The expanding set of PC options
Form Factors
Processing & Graphics
Idle power states
Memory
Storage
Desktop, Laptop, All-In-One
Power & Headroom
Sleep/Hibernate
Large range
A breadth of options
Thin, light
Low-power components
Connected standby
Low RAM for power, cost
Non-rotational storage

6. The broadening ecosystem & optimizations
Cannot rely on hardware performance improvements alone
Engineering best practices today are more critical than ever before
Optimization techniques are similar across range of hardware
Performance considerations
Power considerations
As an app developer, you can choose the range of PCs you want your app to target
Broad range
Narrow range

7. Your app’s ability to perform well across the spectrum of PCs will enable it to reach increasingly broader audiences.

8. The Windows performance/power approach
Minimize consumption
Prioritize UI responsiveness
Scale at runtime to various hardware characteristics
Power
Wake infrequently & at the same time (coalesce)
Stop running when not needed
Windows features
Enabling great performance with HTML
Suspending apps
Reducing the need for startup apps
Getting disk writes out of the way
Conserving memory
Timer reduction, coalescing, resiliency

9. Delivering great experiences across PC hardware

10. Suspending apps What you can do What this buys you
Suspending automatically happens for you!
Users don’t have to worry about background apps
Write Metro style apps
Metro style apps – OS managed background activity
Desktop apps: stop doing work when in background
Desktop apps – no worries about behavior in Connected Standby
Services – throttled in Connected Standby

11. Reducing the need for Startup apps
What you can do
What this buys you
Develop Metro style apps to keep users up-to-date
Minimization of boot, memory, power impact
Use Automatic Maintenance where possible
Metro style apps – best at keeping users connected & up-to-date
Develop hardware-centric Metro style apps
Automatic Maintenance – software updates, etc. at the right time
Hardware-centric apps – automatically downloaded from the store for you

12. Timer reduction, coalescing, resiliency
App 2 activity
App 1 activity
With coalescing
Time
Frequent wakes = inability to enter extreme low power states

13. Timer reduction, coalescing, resiliency
What you can do
What this buys you
Windows 8 has significantly reduced timer wakes by default!
Fewer CPU wakes = less time in “high power” states = better power
Be event driven – don’t “poll” for status
Coalescing = you don’t cause additional wakes = better power
Cancel timers when not in use
Coalesce timers to 5s+ bounds – in Connected Standby, timer coalescing is enforced!
Avoid animating when idle
Never change tick frequency

14. Enabling great performance with HTML
What you can do
What this buys you
Review [162]: “Build Fast & Fluid Metro style apps in HTML5”
Build on IE engine performance
Asynchronous calls & UI responsiveness via WinRT “promise”
Review [386]: “50 performance Tricks to Make Your HTML5 Apps and Sites faster”
Consistently performant touch & animations
Take advantage of advanced features in WinRT & HTML5
Parallelization across cores & UI responsiveness via Web Workers

15. Getting disk writes out of the way
What you can do
What this buys you
Windows 8 already reduces disk I/O in many key areas!
Low priority writes by default
Write coalescing when screen is off
Remove I/O, especially writes
Don’t flush, don’t write unbuffered

16. Conserving memory What you can do What this buys you
Windows 8 already maintains low baseline memory usage!
More apps running at the same time with great performance
Minimize app memory use – think ~50MB
Lower likelihood of your app being terminated
Free memory in background where it’s “cheap” to recreate – Windows does this for you in some cases!
Stop services when not in use

17. Why wait for network? What you can do What this buys you
Don’t assume network connectivity is great!
Uploads/downloads even when your Metro style app is suspended
Use background file transfer API
Optimized impact to power and foreground performance
Use asynchronous network calls
No need to poll - “can I connect to the network yet?”
Use connectivity change API

18. User expectations are the guide
In Windows 8 development, we set user perceived elapsed time goals for various interactions across hardware
Interaction goals are derived from users expectation regardless of the hardware capabilities
Goal: Delight our customers with performance on all Windows 8 PC’s
Best Practices
Recognize the hardware you’re targeting with your app and ensure you are evaluating performance on that target hardware
Identify the key scenarios / interactions users will commonly perform in your app
Instrument your code with start/stop events (ETW, msWriteProfilerMark)
Measure & optimize performance using Windows Performance Analyzer

19. 3 key “do’s”
DO: develop Metro style apps to enable performance and power citizenship by design
DO: take advantage of Windows 8 features to deliver great power/performance across platforms
DO: deliver great performance across platforms to ensure your apps deliver delight for the largest possible audience

20. Related sessions [HW-456T] Understanding Connected Standby
[APP-409T] Fundamentals of Metro style apps: how and when your app will run
[HW-141T] Reducing the memory footprint of drivers and apps
[APP-162T] Building high performance Metro style apps using HTML5
[PLAT-386T] 50 performance tricks to make your Metro style apps and sites using HTML5 faster
[PLAT-785T] Creating connected apps that work on today's networks
[HW-275T] Building and delivering a great Metro style app for your device
[HW-283T] Introducing Metro style device apps

21. Further reading and documentation
Introduction to Background Tasks
Windows Timer Coalescing
Event Tracing for Windows
msWriteProfilerMark documentation
Windows Performance Toolkit
Windows Performance Analysis Developer Center
Windows Hardware Dev Center
Windows Dev Center

22. thank you Feedback and questions http://forums.dev.windows.com
Session feedback

23. 11/30/2018 2:19 PM
© 2011 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2011 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.