Challenge Key Insight: Tunable Visual QoS Results on Fable 3

dJay: Enabling High-density Multi-tenancy for Cloud Gaming
Servers with Dynamic Cost-Benefit GPU Load Balancing
Sergey Grizan, David Chu, Alec Wolman, Roger Wattenhofer
Challenge
Density Optimization Problem
Perceived Quality
max
𝑄(𝑝𝑖 )
𝑖
Challenges
β€’ Predicting πΊπ‘ƒπ‘ˆ_𝑇𝐼𝑀𝐸 𝑝𝑖
β€’ Predicting 𝑄(𝑝𝑖 )
Constraint:
πΊπ‘ƒπ‘ˆ_𝑇𝐼𝑀𝐸(𝑝𝑖 ) < 33π‘šπ‘ 
𝑖
β€’ … for arbitrary scenes
β€’ … for all graphics settings
Impacted by:
β€’ Player churn: join/leave
β€’ Scene change: outdoors/small room
Much lower CapEx and OpEx
Christmas Morning: GPU oversubscription!!
System Architecture
Key Insight: Tunable Visual QoS
HQ
Texture Detail LQ
HI
LO
Ant-Aliasing
Lights
Shadows
Environment details
Fog
Tesselation
GPU time: 3 ms
Perceived quality: 1
GPU time: 1 ms
Perceived quality: 0.7
PSNR, SSIM
Utility Estimating: Cost and Benefit
Results on Fable 3
29 fps
29 fps
40 fps
40 fps
75 fps
0.9999
75 fps
Increasing multi-tenancy
51 fps
51 fps
3 players
16 fps
78 fps
2 players
18 fps
76 fps
78 fps
80 fps
0.9
83 fps
0.99
82 fps
SSIM score
0.999
0
1 player
All HI
All ME
All LO
4 players
dJay
30 fps
30 fps
Increasing scene complexity
0.9999
0.9
0
Simple scene
40 fps
51 fps
20 fps
17 fps
0.99
83 fps
49 fps
SSIM score
0.999
Complex scene
All HI
All ME
All LO
Auto
Responsiveness
45
40
critical level
35
25
20
15
10
5
0
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
60
64
68
72
76
80
84
88
92
96
100
104
108
112
116
120
124
128
132
136
140
144
148
Frame time, ms
30
Frame number
Player 1
Player 2