Multi-core/Cell Game Engine Design

Henry YuPresident & CEO

Kalloc Studios

CredentialsWorked in video game industry for nearly 20

yearsLead Programmer for Sierra-OnlineDirector of Technology for ActivisionTechnical Director for Electronic Arts/

WestwoodSoftware Director for Angel

Studios/RockstarSoftware Engineer Director for THQFound Kalloc Studios 2006

Topics of discussionGame Industry TrendsHardware capabilities comparison

System Architecture Kalloc Studios’ mission

Game Industry TrendsConsumers demand more realistic visuals,

physics interactions, A.I. behaviorsMore game content to give a full,

immersive experienceComputer hardware has been evolving to

utilize multi-core designFaster iteration time to promote rapid

game development

Hardware comparison of the PlayStation 3to the Xbox 360

Multi-core vs. Cell based architecture, different synchronization models

Hard to utilize the SPU due to its small amount of local memory

DMA transfers are difficult to structureSlower RSX graphics performance Memory limitations due to its non-unified

memory architectureSlower Blue Ray Rom data throughput

Fundamental System design Architecture differences between Xbox 360 and PlayStation 3

Core 1

Core 2

Core 3UMA

512 MB

GPU

XBOX 360 system architecture

PPU

SPU SPU SPU SPU

SPU SPU

SYSTEM BUS DMA

SPU SPU

256 MB XDRMain System

Memory

256 MB DDR3Video Local Memory

GPUPlayStation 3 system

architecture

Current Kalloc Engine CapabilitiesCross platform for Xbox 360, PlayStation 3 and PC720p and 1080p high definition support400 or more characters fully skinned with ~5000 polygons

and 91 bones (4 weight influences)50 or more vehicles with ~3000 polygonsNormal mapped charactersAll characters with facial animationsOverall polygon throughput ~24 million polygons per

secondFull collision detection with dynamic objects such as

characters and vehicles NPC driving and responding to collisionsNPC have reactive behaviors toward player’s action

System ArchitectureLocal store and Data Streaming ModelMulti-Threaded Architecture Graphics SubsystemAnimation SystemPhysics ComponentsAsset Pipeline via Live Update System

Local Store and Data Streaming ModelThe architecture works like an array

where individual game objects, physics objects, render objects, etc are each allocated in a contiguous chunk of memory reserved for that type of object.

The contiguous chunk of memory then can be DMA-d over to the PS3 SPU or even cached on the local memory on PS3.

Having objects in contiguous memory is an optimization for the PS3 that will also yield performance increases in Xbox because cache misses will be reduced.

Data Streaming Model to process tasks

SPU Processor

Incoming data stream

Local Store256Kb

Outgoing data stream

DMA Data Bus

DMA Data Bus

Data Streaming Process Model

Multi-threaded ArchitectureThread Based Model and SPU Thread Server

implementation for task based architectureMulti-Threaded Scheduler manages both

blocking and non-blocking processesMulti-stage implementation for data

synchronizationN + 1 frame GPU running concurrently with

core CPU and SPUs

Functional Based multi-threaded ArchitectureFunctional Based architecture associates one

thread per subsystem. All subsystems are processed simultaneously.

Advantages: Very easy to implement since it does not require tasks to be divided and dependencies to be resolved. Suitable for middleware solutions.

Disadvantages: Uneven distribution of processing power since one slower task can hold up the rest of processors, making them idle. Mutexes or some other synchronization protection must be used to resolve data dependencies.

Task Based multi-threaded ArchitectureTask Based architecture uses all threads to process

a subsystem. Subsystems are processed in a given order.

Large tasks must be divided into smaller tasks so that they can be distributed along all processors

Advantage: Extremely even balance of processor power. Virtually eliminates the problem of waiting for the slowest tasks. Due to subsystems being processed in a fixed order, many dependencies are removed, allowing data access without mutex locking.

Disadvantage: Difficult to implement since all tasks are required to be divided and dependencies resolved. Hard to use middleware solutions since this architecture is relatively new.

Task Distribution Model

TASK 8

TASK n

TASK 9

TASK n+1

SPU 0

SPU 1

SPU 2

SPU 3

SPU 4

SPU 5

TASK 5 TASK 6

TASK 2 TASK 3

SPU_SERV

TASK 1

TASK 4

TASK 7

TASK 10

INCOMING TASK SETAvailable SPUs

Solutions to Data SynchronizationMutex locks using critical sectionsData separation using multiple stages (e.g.

read and write stages)Local Store Model using ring buffersComponent object level organization to

separate data dependency

Current Graphics System720p and 1080p native supportInterleaved vertex format with 16-bit normals and UV

data to maximize data throughputMulti-level Shadow Map to enhance resolution qualityUse of instancing to increase rendering performanceDepth Of Field effectHigh Dynamic Range lighting with tone mappingParticle effectsHardware instancing for rendering propsScene graph techniques such as octree and occlusion

systems to further optimize large scale renderingSupports unlimited number of bones for animation

Animation SystemSupport unlimited bones per characterKey frame compressionQuaternion based interpolationSupport for up to 9 channels of animation:

rotation, translation and scaleSupport for overlaid animationsProcedural animation to minimize number of

animations in game

Physics ComponentUse of component system to accommodate

different physics middleware and custom physics engine: Havok, Bullet and Ageia PhysX

Simple custom physics systemSphere to sphere, box to box, box to sphere,

etc collisions2D Grid partition optimizationsPer cell collision detectionSimple vehicle simulation

Instant Asset Update System for Asset pipelineInstant refreshing of assets without

restarting the engine/gameNo intermediate file formats = quick

export process Instant feedback for artists and designers

to check for data validity and qualityNo overnight build/baking processAsset sharing between designers, artists or

programmers within the networkBuilt in support for art outsourcingEasy DVD/Blu Ray burns for archiving and

build delivery

Mission of Kalloc StudiosCreate a truly next gen multi-platform game

engine that maximizes cutting edge hardware such as multi-core and cell architecture and latest graphics rendering capabilities

Create innovative and quality game titlesTrain highly motivated talent to become

industry specialists

Questions ?

Thank you!

henry@kalloc.comjobs@kalloc.comwww.kallocstudios.com

(760) 602-7959