Kerry Turner, a developer relations engineer at Unity Technologies, discusses performance optimization in Unity, focusing on memory usage, load times, and CPU optimization for animations. Key topics include profiling best practices, asset settings for memory management, and the importance of minimizing resources to enhance performance. The document emphasizes using appropriate tools and settings to streamline runtime efficiency and provides guidelines for audio and animation management.

1. Kerry Turner
Developer Relations Engineer
Unity Technologies

2. Real world performance
analysis and
optimisation

3. What we’ll cover
• Memory usage
• Load times
• CPU optimisation: animations

4. What we’ll cover FIRST
• Memory usage
• Load times
• CPU optimisation: animations
• Profiling

5. Profiling:
Best practice
• Profile in real-world conditions
• Don’t profile in the Unity Editor
• Profile on target hardware
• Profile in a typical environment
• Profile the whole state of your game
• Find the cause of your problem
• Understand your resource budget
• Profile before and after you make a change

6. Profiling:
Unity Profiler Window
• Useful for CPU cost of Unity’s internal systems, managed heap size, GC allocs
• Added in 2017.3:
• Experimental support for Deep Profiling in standalone players using Mono
• Profile threaded code using Profiler.BeginThreadProfiling()

7. Profiling:
Unity Frame Debugger
• Useful for examining the commands sent to the
graphics API without platform-specific tools,
learning why draw calls have not been batched
• Added in 5.6:
• Batch breaking information

8. Profiling:
Unity Memory Profiler
• Useful for identifying assets that are inappropriately
large, or that should not be resident in memory
• Download from
bitbucket.org/Unity-Technologies/memoryprofiler
• 2017.3:
• Support for Mono .NET 3.5 runtime

9. Profiling:
Platform-specific tools

10. Runtime memory usage:
Asset settings
• Create asset rules
• Enforce asset rules using AssetPostProcessor scripts
• Download Asset Auditor from
github.com/MarkUnity/AssetAuditor

11. Runtime memory usage:
Asset complexity
• Overly large and complex source assets are a very common cause of excessive
runtime memory usage
• Identify overly large or complex source assets by examining a memory
snapshot and auditing assets
• Reducing source asset size and complexity has other benefits
• Faster asset load times
• Meshes with fewer vertices = reduced vertex processing cost on GPU
• Lower resolution textures = reduced texture read cost on GPU
• Animations with fewer curves = reduced animation cost on CPU
• This is a good example of where asset rules can prevent human error

12. Runtime memory usage:
Read/Write Enabled Textures
• Read/Write Enabled = 2 copies of texture
• 1 in GPU memory, as usual
• 1 additional copy in CPU memory
• Enable Read/Write Enabled only if:
• You get pixels in code
• You set pixels in code
• Disabling Read/Write Enabled reduces texture size in memory by 50%

13. Runtime memory usage:
Read/Write Enabled Textures
• Texture2D instances created in code are read/write enabled by default
• Make Texture2D instances read-only by calling
texture2D.Apply(updateMipmaps, true);
• This uploads the texture from main RAM to the GPU
• If makeNoLongerReadable is true, the copy in main RAM is then discarded

14. Runtime memory usage:
Mip maps
• Mip maps add 33% to texture size
• Generate Mip Maps defaults to true
• Enable Generate Mip Maps only if:
• Texture distance from camera varies
• This is another great example of where an asset rule can fix incorrect settings

15. Runtime memory usage:
Read/Write Enabled Meshes
• Read/Write Enabled = 2 copies of mesh
• 1 copy in GPU memory, as usual
• 1 additional copy in CPU memory
• This can more than double the size of a mesh in memory
• Enable Read/Write Enabled only if:
• You access the mesh properties in code
• You are using a MeshCollider and the mesh transform has negative scaling
• You are using a MeshCollider and the mesh transform is skewed or sheared

16. Runtime memory usage:
Read/Write Enabled Meshes
• Mesh instances created in code are read/write enabled by default
• Make mesh instances read-only by calling
mesh.UploadMeshData(true);
• This uploads the texture from main RAM to the GPU
• If markNoLongerReadable is true, the copy in main RAM is then discarded

17. Runtime memory usage:
Vertex Compression
• Applied in Player Settings
• Uses half precision (16-bit floats)
for selected vertex channels
• Applied to all eligible meshes in project,
including those generated by static batching,
except when it is overridden
• Not compatible with SkinnedMeshes until 2018.2
• From 2018.2, SkinnedMeshes can use
Vertex Compression for texture co-ordinates only

18. Runtime memory usage:
Vertex Compression
• Vertex Compression cannot be applied when:
• A mesh has Mesh Compression applied
• Mesh Compression is a lossy compression that affects size on disk only
• Mesh Compression is applied to individual mesh assets at import time
• To use Vertex Compression on a mesh, disable Mesh Compression
• A mesh is read/write enabled
• When a mesh is read/write enabled, 2 uncompressed copies are resident
in memory

19. Runtime memory usage:
Animation Compression
• Animation Compression allows some control over how Unity processes and
represents a clip’s curve and keyframe data
• Adjust precision using Animation Compression Errors settings

20. Runtime memory usage:
Animation Compression
• Off (default)
• Keyframe reduction
• Applied after import, iterates over each curve and removes
redundant keyframes
• Optimal (Generic and Humanoid only)
• Applied at build time, allows for use of Dense curve type for additional file
size reduction
• Recommended settings:
• Legacy: Keyframe reduction
• Generic or Humanoid: Optimal

21. Runtime memory usage:
Audio Load Type
• Recommended settings:
• Streaming if >1 MB
• Compressed in memory if >200 KB and <1MB
• Decompress on Load if <200 KB

22. Audio compression format:
Compression ratio
ADPCM 27.5%
Vorbis 100% 31.0%
MP3 100%. 22.2%
Vorbis 50% 11.0%
MP3 50% 11.0%
27.50
31.00
22
11
11
0 8.25 16.5 24.75 33
ms

23. Audio compression format:
CPU time to load
ADPCM 1.4%
Vorbis 100% 12.0%
MP3 100%. 6%
Vorbis 50% 7.8%
MP3 50% 7.5%
1.40
12.00
6
8
8
0 3.75 7.5 11.25 15
%

24. Audio compression format:
Conclusions
• ADPCM is by far the fastest to load, but offers a relatively poor
compression ratio
• At 100% quality, MP3 significantly outperforms Vorbis in terms of
compression and load time
• At 50% quality, Vorbis and MP3 have very similar performance
• Recommended settings:
• Short clips: ADPCM
• Long clips: Vorbis or MP3

25. Load times:
GetScriptingClass()
1110 ms 1.10
0.9 1.2
ms

26. Load times:
GetScriptingClass()
1110 ms
20ms
1.10
0.02
0 0.3 0.6 0.9 1.2
ms

27. Load times:
GetScriptingClass()
• MonoManager::GetScriptingClass() searches assemblies for class types during
application startup
• Performance regression led to this function taking up to 50% of application
startup time in IL2CPP projects
• This was due to inefficient string operations
• Fixed in 2018.2
• String operations have been replaced with a hash map
• Patched to all versions of Unity 2017

28. Load times:
ETC Crunch Textures
• Crunch compression is a lossy texture compression format that provides
additional file size savings
• Unity moved to a new Crunch library in 2017.3
• Before 2017.3, Unity could apply Crunch to DXT only
• From 2017.3, Unity now allows for Crunch compression of
• ETC_RGB4
• ETC2_RGBA8

29. Load times:
ETC Crunch Textures
ETC 6.7 MB
ETC 1.8 MB
Crunch
67.00%
18.00%
0 37.5 75 112.5 150
ETC
ETC Crunch

30. Load times:
ETC Crunch Textures
ETC 6.7 MB
49 ms
ETC 1.8 MB
Crunch 133ms
67.00%
18.00%
49.00%
133.00%
0 37.5 75 112.5 150
ETC
ETC Crunch

31. Animation CPU optimisation:
100 animations with 12 curves
Legacy 4ms
Generic 9ms
4.00
9.00
-4.5 3 10.5 18 25.5 33
ms

32. Animation CPU optimisation:
100 animations with 640 curves
Legacy 19ms
Generic 13ms
Humanoid 26ms
19.00
13.00
26
0 8.25 16.5 24.75 33
ms

33. Animation CPU optimisation:
Conclusions
• Unity Animation System becomes more efficient with a higher
number of curves
• Recommended settings for lower-end devices:
• Unity Animation System for clips with >300 curves
• Legacy Animation System for clips with <300 curves

34. Animation CPU optimisation:
Humanoid or Generic?
• Humanoid performs operations related to retargeting, root motion and
IK every frame, regardless of whether those features are used
• Recommended settings:
• Humanoid when using retargeting and IK
• Generic in all other cases

35. Animation CPU optimisation:
Culling Mode
• Culling Mode allows you to configure how an Animator behaves when offscreen
• Always Animate (default)
• Performs all operations when culled
• Cull Completely
• Performs no operations when culled
• Cull Update Transforms
• Updates internal state but skips transform writes, retargeting and IK when
culled

36. Animation CPU optimisation:
Animator bindings
• Before 2018.1, Animators discard buffers and bindings when GameObject is
deactivated
• This results in CPU spikes when GameObject is reactivated
• From 2018.1, retain buffers and avatar bindings when GameObject is deactivated by
calling:
keepAnimatorControllerStateOnDisable = true;
• This can be set via script only, and is not visible in the Inspector
• Be aware of memory usage of deactivated Animators with this set to true

37. One last tip:
More talks like this
• Unite Europe 2017 - Squeezing Unity
• Unite 2016 - Let's Talk (Content) Optimization
• Unite Europe 2016 - Optimizing Mobile Applications

38. Thank you!