Android Performance Optimisation

This presentation covers practical aspects of performance optimisations for Android apps, including UI and Layouts performance, batching and caching, memory performance, battery optimisations.

Transcript

1. Android Performance Tuning Sergii Kozyrev
2. www.web-academy.com.ua INTRO
3. www.web-academy.com.ua Agenda • UI –UI performance issues and tuning –GPU overdraw localisation –Solving with layout changes –Solving with canvas api • Computational speed and performance –Finding bottlenecks - using Traceview and systrace –Ways to solve speed performance issue • Memory issues –Identifying memory issues - memory monitor, heap viewer, allocation tracker –Few hints to minimize number of objects • Battery issues –Battery drain problems with battery historian –How to save some battery
4. www.web-academy.com.ua Tools, not rules Gather info -> Gain insight -> Take Action
5. www.web-academy.com.ua User Interface
6. Android UI - how it works • ui update + draw() -> every 16 ms (60 FPS) • this is due to 1000ms/60Hz = 16.6 ms per frame • all drawing logic in 16 ms frame - if You miss - “dropped frame :( ” - leads to non smooth animation
7. www.web-academy.com.ua How it works
8. www.web-academy.com.ua How it works
9. www.web-academy.com.ua Design vs Performance?
10. www.web-academy.com.ua Small issue -> big problem • Multiple dropped frames could lead to much bigger problems • Especially in collection views such as list view
11. www.web-academy.com.ua Rendering flow • CPU • measure • layout • record • execute • GPU • Rasterization Layouts and Invalidations Overdraw
12. www.web-academy.com.ua Every problem can be addressed with special tool

13. www.web-academy.com.ua Understanding of the process is a key!
14. www.web-academy.com.ua Rasterization • High level object to pixels • CPU responsible to feed polygons and textures to GPU (Open GLES process) • Preparing on CPU and uploading to GPU - both are not fastest processes • Android does a lot to optimise - example is loading of all resources as one texture to the GPU
15. www.web-academy.com.ua Overdraw • “Repainting of wall” - wasting Your time :) • How many times a pixel on the screen has been redrawn in a single frame • Example - deck of cards widget • Turn overdraw debug in settings!
16. www.web-academy.com.ua Overdraw (display list rebuild too many time during frame or spending too much time invalidating)
17. www.web-academy.com.ua Overdraw Red is BAD Blue is GOOD
18. www.web-academy.com.ua Two main ways to go to GOOD side • First - remove unneeded backgrounds from XML • Mark areas of the screen that overlaps manually - use API
19. www.web-academy.com.ua DEMO XML backgrounds
20. www.web-academy.com.ua Canvas api to fix overdraw: clipRect() and quickReject()
21. www.web-academy.com.ua DEMO Canvas API
22. www.web-academy.com.ua Layouts and invalidation • DL - Display List contains • UI Object -> Create DL -> Execute DL • If view unchanged - re-executing same display list • Invalidate -> recreate all DL • change size - measure of view changes -ask each view in hierarchy about new sizes • change position - layout phase traversing the hierarchy
23. www.web-academy.com.ua More views - more touches from system DEMO Hierarchy viewer
24. www.web-academy.com.ua LAB
25. www.web-academy.com.ua Computational speed
26. www.web-academy.com.ua Slow function performance • Most of the time depends on how You write code • Almost doesn’t depend on hardware
27. www.web-academy.com.ua Two Flavors • Single slow performance function • “Death of a thousand cuts” - each function is a bit slower • Slow performance func - when it runs slower then You expected
28. www.web-academy.com.ua Fixing compute performance is all about profiling
29. www.web-academy.com.ua DEMO traceview
30. www.web-academy.com.ua Batching and Caching • It is all about caching in computer (inside and outside) • CPU-CPU(cache) <-> RAM <-> Hard Drive • Laptop <-> local data center <-> photo of a cat in SF
31. www.web-academy.com.ua Batching and Caching • Fast algorithms already in place in language • Find lines of code that can be done just once • Find architecture solution that enable caching
32. www.web-academy.com.ua DEMO Traceview fib()
33. www.web-academy.com.ua Blocking UI thread • Network access • File system access • Database access • Time consuming computation
34. www.web-academy.com.ua More then 5 seconds block - user will get “ANR” dialog
35. www.web-academy.com.ua Async • Java Thread and AndroidHandlerThread • AsyncTask • Loader • IntentService • JobScheduler
36. www.web-academy.com.ua DEMO traceview ain thread
37. www.web-academy.com.ua Performance of primitives
38. www.web-academy.com.ua Algorithm Performance • Merge sort, quicksort etc. • how about:
39. www.web-academy.com.ua Performance is not free • Java Vector (LinkedList): • push O(1) • pop O(1) • insert O(n) • remove O(n) • search O(n)
40. www.web-academy.com.ua Other examples • Hashtable > “fastest” • HashMap > • LinkedHashMap > • IdentityHashMap > • ConcurrentHashMap > • HashSet “slowest”
41. www.web-academy.com.ua It is all about how You use it
42. www.web-academy.com.ua DEMO systrace
43. www.web-academy.com.ua LAB
44. www.web-academy.com.ua Memory
45. www.web-academy.com.ua Garbage Collector is such a cool feature
46. www.web-academy.com.ua There is always taxes - remember, “performance is not free”? :)
47. www.web-academy.com.ua Understanding memory • GC • Find objects that can’t be accessed • Reclaim the resources • Questions: • Heap vs Stack memory? • What GC collects? • How leaks happens?
48. www.web-academy.com.ua Concerns

49. www.web-academy.com.ua Memory Leaks • It’s not only about OutOfMemoryError • It reduces available memory and causes GC run more frequent - which is bad
50. www.web-academy.com.ua DEMO Memory Monitor
51. www.web-academy.com.ua Memory Leaks • Simple - “handler case”, or every circular referenced objects • Complex - holding a handle to the ClassLoader objects, load in onCreate and don’t check if classes already loaded (no class unload procedure)
52. www.web-academy.com.ua DEMO HeapViewver
53. www.web-academy.com.ua Move allocations out of inner loops :)
54. www.web-academy.com.ua DEMO Allocation Tracker
55. www.web-academy.com.ua LAB
56. www.web-academy.com.ua BATTERY
57. www.web-academy.com.ua What is more important - preserved battery or uploaded cat’s photo?
58. www.web-academy.com.ua Battery drain options • Screen • CPU • Cellular Radio
59. www.web-academy.com.ua Deferred tasks • Some tasks may be deferred: • Upload photos • Apply filters • Import data from datasource • Sync media files • Send instant message
60. www.web-academy.com.ua DEMO Battery Historian
61. www.web-academy.com.ua • WakeLock is BAD Deferred AlarmManager is GOOD
62. www.web-academy.com.ua Where we can save battery
63. www.web-academy.com.ua DEMO JobScheduler is even better
64. www.web-academy.com.ua LAB
65. www.web-academy.com.ua OUTRO
66. www.web-academy.com.ua Thank You!