The presentation focused on performance challenges I've come across when working on real-world WP7 applications using Silverlight. These challenges include optimizing startup time of applications, using ListBox with a large number of items, serialization / deserialization, working with images, accessing the network and realtime drawing on the screen.

1. WP7 Performance Challenges GergelyOrosz @GergelyOrosz

2. WP7 Performance Challenges My Experience Everyday performance challenges Visually rich app performancechallenges Computing intense performance challenges

3. My Experience

4. Cocktail Flow

5. Cocktail Flow Challenges Serialization / Deserilaization Animations Downloading packages: networking Rich ListBoxes Emulator vs physical device

6. Visiblox Charts for WP7

7. Visiblox Charts for WP7 Challenges Avoiding overloading of the UI thread Realtime drawing on the screen How fast can you draw on the phone? Memory Leaks Data binding DPs

8. EverydayPerformance Challenges

9. Networking & the UI Question

10. Networking & the UI WebClient: simple, easy … runs on the UI thread! HttpWebRequest: complicated &performant

11. Serialization & Deserialization XmlSerializer

12. Serialization & Deserialization Binary Serialization DataContractSerializer Json.NET sharpSerializer Mike Talbot’s Silverlight Serializer Sterling Isolated Storage DB Ninja Database Pro

13. Serialization & Deserialization Load Save

14. ListBox Cool in the beginning Rusty when you start adding stuff Awfully slow when you start tweaking visuals Pain to make it half as fast as on the iPhone

15. ListBox Slow with > 50-200 elements Virtualized, but…. Several workarounds Windows Phone Team: ListBox best practices 3rd party Listbox (Telerik) Implement paging

16. Emulator vs Physical Device Emulator usually 2-5x times faster GPU intensive tasks: emulator can be slower Test (frequently) on the device

17. Small Things ProgressBar Splashscreen while loading  PerformanceProgressBar

18. Visually Rich App Performance Challenges

19. Frame Rate Counters FPS (render > 30, UI > 15) Texture mem. usage Fill Rate (<2.5) Blog post explaining these

20. BitmapCachevs No Caching No caching  GUP calculates every time BitmapCache  “screenshot” saved, no GPU needed

21. BitmapCachevs no Caching

22. Image Do’s and Don’t‘s Fast (with BitmapCache): Transforms: Scale, Rotate, Translate Opacitiy change Clipping region change Slow Changing image with / height OpacityMask Non-rectangular clipping areas Jpegs are (somewhat) faster than pngs

23. Computing Intensive Applications

24. Avoid Overloading the UI Thread Use BackgroundWorker Throttle calls to UI while it’s busyvia the “render loop”: E.g a chart is redrawn whenever the Zoom changes A chart redraw takes 100ms The Zoom is changed at 0ms, 40ms, 80ms, 120ms The chart will still be drawing at 40ms & 80ms!

25. Rendering Real-Time Lightweight vs heavyweight elements Shapes vs Controls vsUserControls Drawing is more expensive than redrawing Reuse existing elements WriteableBitmap & WriteableBitmapEx Working with large Paths: buggy, slow

26. Extreme Optimalizations Data Binding Avoid when there are thousands of objects Takes up memory & notifications may fire too often DPs Only use if needed Slow to read  cache in CLR properties

27. Summary Networking & effect on UI thread Serialization & deserialization ListBox BitmapCaching

28. Closing Thoughts Use the performance counters Performance can be optimized (or you can always cut features…) Test, test, test - on a device! MIX 2011 – performance tool?