Unity mobile game performance profiling – using arm mobile studio

Confidential Restricted to Arm Exec Committee © 2021 Arm
Owen Wu(owen.wu@arm.com)
2021/07/10
TGDF 2021
Unity Mobile Game
Performance Profiling –
Using Arm Mobile
Studio

2 Confidential Restricted to Arm Exec Committee © 2021 Arm
Test Content

Unity
Frame Debugger
and Profiler

Unity Profiler
• It’s very useful to know which task is most expensive
• We can see Render Camera took 73.04 ms
• Then we can see Post-Processing in the most expensive task in Render
Camera(62.17 ms)
• Then we finally found Bloom effect took 57.89 ms should be the bottleneck

Frame Debugger
• It is very useful to know how a frame is rendered
• The first thing we found is that the camera renders at full screen resolution
2340x1080
• Modern mobile usually has a very high resolution screen and we can
render to smaller texture then up scale

Post-Processing
• As bloom is the most expensive post-processing, we can check what is
going on for bloom
• We can see there are 25 draw calls for bloom, each has half resolution of
previous draw call
• So we can reduce the Render Camera resolution which also reduce the
number of draw calls

Fixed Timestep
• Default is 50Hz or 0.02 timestep
• Our FixedUpdate() is short enough to be called multiple times per frame
• 0.04 timestep is suggested for aiming 30 fps
• 0.033 timestep may end up two updates per frame sometimes
• Make sure the FixedUpdate() is called only once per frame

Arm Mobile Studio

Low Level Profiling with Arm Mobile Studio
• Unity profiler and frame debugger is good for high level profiling
• But we still need low level profiling on real device
• Arm Mobile Studio is a free tool for low level profiling on Mali GPU
• Arm Mobile Studio includes 4 tools for different perspectives
• Performance Advisor
– Generate easy-to-read reports and get optimization advice
• Streamline
– Comprehensive performance profiler, to capture all the counter activity
• Mali Offline Compiler
– Check how a shader program would perform on a Mali GPU
• Graphics Analyzer
– Debug graphics API calls and analyze how content was rendered

Performance Advisor
Analysis Reports
Fast workflow
 Integrate data capture and analysis
into nightly CI test workflow
 Read results over a nice cup of tea
Caveats …
 Still under development, so
not included in 2019.0
 Limited access beta program if you
are happy to provide input
Overview charts
Region views
 Split by dynamic
behavior
 Split by application
annotation
Executive dashboard
 Show high level status summary
 Show status breakdown by regions
of interest
 See performance
trends over time
 See region splits
basis
Summary reports
 Easy-to-use performance
status reports
 Integrated initial root cause
analysis

Performance Advisor
Show average
FPS data
Show the game is
fragment bound
Show the GPU is
busy but CPU is
idle at the most
of time
Show the bond
based on
timeline
Capture the
screen when FPS
is low

GPU Cycles per Frame We can add GPU cycle budget for
30 fps. Here we set 28M cycles
as the budget.
850MHz/30 = 28M/frame

Shader Cycles per Frame The execution engine is the most busy
unit in shader core. Execution engine
is responsible for shader execution
and arithmetic operations.

Vertices per Frame
We can also set budget here as the green line shows.
We can see the amount of vertices increased over time.

Primitives per Frame
The total primitives increased over time but
visible primitives is not. It turns out the dead
enemies are not destroyed even they are invisible.

Streamline
Performance Analyzer
Mali GPU support
 Analyze and optimize Mali™ GPU
graphics and compute workloads
 Accelerate your workflow using
built-in analysis templates
Optimize for energy
 Move beyond simple frame time
and FPS tracking
 Monitor overall usage of processor
cycles and memory bandwidth
Speed up your game
 Find out where the system is
spending the most time
 Tune code for cache efficiency
Application event trace
Native code profiling
 Break performance
down by function
 View cost alongside
disassembly listing
Arm CPU support
 Profile 32-bit and 64-bit apps for
ARMv7-A and ARMv8-A cores
 Tune multi-threading for
multi-core and big.LITTLE systems
 Annotate software
workloads
 Define logical event
channel structure
 Trace cross-channel
task dependencies
Tune your rendering
 Identify critical-path GPU
shader core resources
 Detect content inefficiency

Streamline Analysis The visible primitive rate is only 34.4%. It means
we sent many invisible primitives to GPU. It
matches the result of Performance Advisor. We
should cull those invisible primitives on CPU.
Back facing primitive rate is 49.5%. It is
reasonable since normally about 50% primitives
are back facing.
Sampling cull rate is 31.9%. It usually means that
there is micro triangle issue.

Streamline Analysis
Partial coverage rate is 72.3% and it is pretty high. It
means there are many quads are partial covered
which is usually caused by micro triangle. Partial
coverage is pretty expensive for hardware.

Streamline Analysis - Shader Precision
This counter shows that the most interpolations are
32 bits. It matched the result of Performance
Advisor. 32 bits interpolation is twice slower than
16 bits interpolation.

s
Mali Offline Compiler
Shader static analysis
Rapid iteration
 Verify impact of shader changes
without needing whole application
rebuild
Profile for any Mali GPU
 Cost shader code for every Mali
GPU without needing hardware
Mali GPU aware
 Support for all actively
shipping Mali GPUs
 Cycle counts reflect
specific microarchitecture
Critical path analysis
Control flow aware
 Best case control flow
 Worst case control flow
Syntax verification
 Verify correctness of code changes
 Receive clear error diagnostics for
invalid shaders
 Identify dominant
shader resource
 Target this for
optimization!
Register usage
 Work registers
 Uniform registers
 Stack spilling

Shader Analysis with Mali Offline Compiler
Mali Offline Compiler v7.3.0 (Build 002baf)
Copyright 2007-2020 Arm Limited, all rights reserved
Configuration
=============
Hardware: Mali-G72 r0p3
Architecture: Bifrost
Driver: r25p0-00rel0
Shader type: OpenGL ES Fragment
GPU information.
Driver information.

Main shader
===========
Work registers: 64
Uniform registers: 26
Stack spilling: false
16-bit arithmetic: 2%
A LS V T Bound
Total instruction cycles: 17.33 0.00 3.75 2.00 A
Shortest path cycles: 11.27 0.00 0.50 0.00 A
Longest path cycles: 17.33 0.00 3.75 2.00 A
A = Arithmetic, LS = Load/Store, V = Varying, T = Texture
Only 2% arithmetic is mediump. Mediump is 2 times
faster than Highp.
Shader is arithmetic bound. It matches the result of
Performance Advisor.

Shader properties
=================
Has uniform computation: true
Has side-effects: false
Modifies coverage: true
Uses late ZS test: false
Uses late ZS update: true
Reads color buffer: false
Note: This tool shows only the shader-visible property state.
API configuration may also impact the value of some properties.
Unnecessary uniform computation in shader. Should
be moved to CPU.
Instruction like discard() will force shader to do late
Z update.
Shader logic is forcing shader to do late Z update.

Graphics Analyzer
GPU API Debugger
Shader analysis
 Capture and view all shaders used
 Debug and optimize performance
issues using the integrated Mali
Offline Compiler
Cross platform
 Host support for Windows, Linux
and Mac
Advanced API debug
 Graphics debug for content
developers
 Support for all versions of
OpenGL ES and Vulkan
Android application
Visual analysis views
 Native mode
 Overdraw mode
 Shader map mode
 Fragment count mode
State visibility
 Show API state after every API call
 Trace backwards from point-of-use
to triggering API call which caused
a specific state to change
 Manage on-device
connection
 Select and launch
user application
Frame analysis
 Diagnose root causes of
rendering errors
 Identify sources of
rendering inefficiency

Graphics API Call Analysis with Graphics Analyzer

• Use mesh LOD to avoid micro triangle issue.

Arm Mobile Studio
• Starter Edition
• https://developer.arm.com/mobile-
studio
• Professional Edition
• https://developer.arm.com/mobile-
studio-pro

Q & A
• Send your questions to : owen.wu@arm.com
• Visit developer.arm.com :
https://developer.arm.com/solutions/graphics-and-gaming
• More Unity resources :
https://developer.arm.com/solutions/graphics-and-
gaming/gaming-engine/unity

Thank You
Danke
Gracias
谢谢
ありがとう
Asante
Merci
감사합니다
धन्यवाद
Kiitos
‫ا‬ً‫شكر‬
ধন্যবাদ
‫תודה‬

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