1. Hazel McKendrick
Supervised by Henry Fortuna
Distributing
Virtual Worlds
“How can the processing of autonomous characters
in a real-time virtual environment benefit from
parallelisation over multiple distributed computer
systems?”

2. Project Overview.

Processing virtual worlds

Single server unsuitable

Flexibility, scalability, redundancy

Distributed computing

3. Project Aim.

Create a distributed system

Divide a virtual world

Update characters in it

Consider:
• Processing power
• Scalability, power and money saving
• Flexibility

4. Simulation Design.

World Maps

Characters (thousands)
• A* Pathfinding

5. System Structure.

Server & Worker Node architecture

TCP-IP

Message Passing

Node thread pool

6. World Division.

Top-down vs Bottom-up
Microcells

Smallest unit of world

Nodes process several

Distributed statically or
dynamically

Contain and pass work

7. Distribution.

Optimal assignment
• Can be solved with ILP - Complexity too high

Two static approaches used

Dynamic algorithm created

8. Distribution Results.

Amdahl's Law

95% to 99% parallelised
Processing times with varying numbers of nodes
450.000 Average deviation in processing times, over time
4
400.000
3.5
350.000 Server
Average deviation(ms)
Node 1 3
Processing time (ms)
300.000 Node 2
2.5
Node 3
250.000
Node 4 2
200.000 Node 5
1.5
Node 6
150.000 Node 7 1
Node 8
100.000 0.5
Node 9
50.000 0
0 1 2 3 4 5 6
0.000
Time elapsed (minutes)
0 1 2 3 4 5 6 7 8 9 10 11
Number of computers

9. Scaling Hardware.

Virtual world load varies greatly

Gustafson's Law
Minimising Hardware

Scale Hardware Entities Nodes on
Improve
5000 3

4500
4000
distribution! 3500
2
3000
Entities
Nodes
2500
2000
(Simulated)
1
 1500
1000
500
0 0
0 20 40 60 80 100 120 140
Time (s)

10. Evaluation.

Scaling nodes

Dynamic distribution algorithm
• Over time

Microcells

Reducing hardware

11. Conclusion.

Reduce processing times

Balance load

Lower power and cooling costs

Further work
• Redundancy
• Inter-node communications
• Scaling factors

12. Hazel McKendrick
Supervised by Henry Fortuna
Distributing
Virtual Worlds
“How can the processing of autonomous characters
in a real-time virtual environment benefit from
parallelisation over multiple distributed computer
systems?”