Valentin Simonov, Field Engineer, Unity Technologies

1. Valentin Simonov
Field Engineer / Unity Technologies
val@unity3d.com

2. Valentin Simonov — Field Engineer
Email: val@unity3d.com
• I help studios make games better
• I teach people how to use Unity efficiently
(conferences, trainings, blog posts, translated a book on shaders)
• I maintain https://github.com/TouchScript/

5. 1. Why is it not working?

6. LET’S START
OPTIMIZING

7. 1. Get data about your project (tools)
2. Interpret that data (knowledge)
3. Make a list of possible optimizations (management)
4. Perform necessary* optimizations (business)

8. 1. Get data about your project (tools)
2. Interpret that data (knowledge)
3. Make a list of possible optimizations (management)
4. Perform necessary* optimizations (business)

9. How to get correct data and eliminate guess work.
1. Unity Profiler
2. Unity Frame Debugger
3. Unity Memory Profiler
( https://bitbucket.org/Unity-Technologies/memoryprofiler )
4. Platform tools

10. How to make correct decisions based on collected data.
1. Blogs, forums, learning materials
( https://unity3d.com/learn/tutorials/topics/best-practices )
2. Videos from conferences
3. Trainings

12. • Shows code execution time and GC allocations
• Can be connected to a remote device
• Deep Profile in Editor

13. • Profiler.BeginSample() / Profiler.EndSample()

14. • Profiler.BeginSample() / Profiler.EndSample()
FRAME
CPU HAS TO WAIT
PREVIOUS FRAME GPU WORK THIS FRAME GPU WORK

15. Always test on target device!
1. Editor code is different
2. Target hardware is different

17. https://bitbucket.org/Unity-Technologies/memoryprofiler
1. Open this project in Unity
2. Connect to a development build
3. Grab snapshot
4. Have fun!

18. private Texture2D tex;
var bundle = AssetBundle.LoadFromFile(...);
tex = bundle.LoadAsset<Texture2D>(”img");
bundle.Unload(false);

19. var bundle = AssetBundle.LoadFromFile(...);
var texture =
bundle.LoadAsset<Texture2D>(”img");
bundle.Unload(false);

20. static List<Texture2D> list;
var bundle = AssetBundle.LoadFromFile(…);
list.Add(
bundle.LoadAsset<Texture2D>(”img"));
bundle.Unload(false);

21. Apple Instruments: Time Profiler, Allocations
• Shows everything
• Accurate stack trace
• CPU time on device
• Can save/load traces

22. Statement:
1. The game is leaking memory.
2. Unity Profiler shows memory growing…
3. ... but doesn’t show any allocations from scripts.

25. • Do you know these tools?
• Do you use them?
• Does your team use them?

27. “The trouble with quotes
on the Internet is that
you can never know if
they are genuine.”
Abraham Lincoln

28. Internet is full of
• Outdated information
• Advice not applicable to your platform
• Information which is just wrong

29. Light and heavy draw calls.

30. * on your target platform/device

31. Using Resources folder is generally not advised:
1. All “Resources” folders are packed in a monolithic binary
2. Rebuilt every time even if nothing has changed
3. 4 Gb size limit, uncompressed
4. More assets -> slower loading
5. At start time Unity builds index and always keeps it in memory

32. • 12 000 1px images in Resources
• Look for ResourceManager::Transfer
• CPU time depends on device (iPhone 4s on the pic below)

33. What are these shaders?

34. Internal-ErrorShader
Normal-VertexLit
Normal-Diffuse
Internal-StencilWrite
Internal-DepthNormalsTexture
Internal-PrePassLighting
Internal-ScreenSpaceShadows
Internal-CombineDepthNormals
Internal-BlitCopy
Internal-DeferredShading
Internal-DeferredReflections
Internal-MotionVectors
Internal-Flare
Internal-Halo
Internal-GUITextureClip
Internal-GUITextureClipText
Internal-GUITexture
Internal-GUITextureBlit
Sprites-Default
UI-Default
UI-DefaultFont
CubeBlur
CubeCopy
CubeBlend
Skybox-Procedural

36. Keep in mind platform specific behaviors.
For example, that iOS caches compiled shaders.

37. Question: What is the fastest way to dynamically create 1000 complex
objects?
Complex object — 10 children with 10 components each.
1. Create 10 children, add 10 components to each, repeat.
2. Create 1 template object with 10 children, clone it 999 times.
3. Instantiate a prefab, repeat.
Target device: iPhone 6, Unity 5.4.1

38. 1. Create 10 children, add 10 components to each, repeat.
1562.250 ms
2. Create 1 template object with 10 children, clone it 999 times.
451.394 ms
3. Instantiate a prefab, repeat.
485.250 ms
4. Clone a prefab, instantiate the clone 999 times.
432 ms

39. 1. Create 10 children, add 10 components to each, repeat: 1562.250 ms

40. 2. Create 1 template object with 10 children, clone it 9999 times.
451.394 ms

41. 1. Create 1 template object with 10 children, clone it 999 times.
440.593 451.394 ms
2. Clone a prefab, instantiate the clone 999 times.
422.5 432 ms
3. Instantiate a DISABLED prefab, repeat.
412.5 422.5 ms

43. THIS GUY!

44. 1. There’s native (C++) and managed (C#) memory
2. Assets live in native memory
3. Managed memory has light wrappers for assets
Texture2D myTexture = …
(a) myTexture = null; — wrapper is GCd, texture data is stuck
(b) Destroy(myTexture); — wrapper is stuck, texture data is freed
(c) Resources.UnloadUnusedAssets(); — destroys stuck assets
(d) GC.Collect(); — GCs stuck wrappers (at this point destructors are called)

45. • WWW www = new WWW(…)
-> allocate buffers
• www.Dispose() -> DestroyWWW()
-> release buffers
• GC(?)-> www.~WWW() ->
DestroyWWW()
-> release buffers
WWW wrapper
WWW data
Managed

46. • Unity is a C++ engine with a .NET virtual machine
• Calling Managed functions from Native involves some overhead
• Every Awake/Start/Update* call is a call from Native to Managed
• ... even empty ones o.O
• At some point you will start noticing this overhead

47. https://blogs.unity3d.com/2015/12/23/1k-update-calls/

48. • Find, FindObjectOfType — super slow!
• Camera.main doesn’t cache the main camera
• APIs which return arrays allocate memory every time

49. 1. Unity open source projects
https://bitbucket.org/Unity-Technologies/ui
https://github.com/Unity-Technologies/PostProcessing
2. UnityEngine.dll -> ILSPY
http://va.lent.in/unity-make-your-lists-functional-with-reorderablelist/
3. Time Profiler instrument and other tools.

51. Valentin Simonov
Field Engineer / Unity Technologies
val@unity3d.com