assaf shacham, keren bergman, luca p. carloni presented for hpcan session by: millad ghane nocs’07
TRANSCRIPT
On the Design of a Photonic Network-on-Chip
Assaf Shacham, Keren Bergman, Luca P. Carloni
Presented for HPCAN Session by: Millad Ghane
NOCS’07
Why NoC ?
Scaling Transistor Speed and Integrity Tighter Logic Power Dissipation
Increasing Number of Cores per Chip Bottleneck: Global Intrachip Communications▪ Bandwidth▪ Power
Performance-per-watt
Why Optic ?
Low Power Dissipation Ultra-high Throughput Minimal Latency End-to-end Transmission
No Repeating No Regeneration No Buffering
A silicon ring
resonator
Hybrid Architecture
Photonic Interconnection High Bandwidth Messages
Electronic Interconnection Low Bandwidth Messages Short Control Messages
Photonic Properties
Advantages Bit-rate Transparency▪ Not Switching by Every Bit of Data▪ Switching Once per Message
Low Loss in Optical Waveguide▪ Independence of Transmission Distance
Disadvantages No Storage Element E/O and O/E Conversions▪ Off-chip Lasers
Packet Life
D
D
SSending path-setup packet
Electronic Network
Optic Network
S
Packet Life
D
S D
SSending optical packet
Packet Life
D
S D
SSending path-teardown packet
Packet Life
D
S D
SSending path-blocked packet
path-teardown packet
Building Blocks
70 µm
70 µm
Photonic Switching Element
Electrical Router
Building Blocks Problems
No Injection/Ejection Port Not Deadlock-Free
Wide Turns
Approach
Injection
Torus Address
Ejection
Gateway Switch
Injection Switch
Ejection Switch
Torus Network Nodes
Access Points Address
Format
Deadlock Solution
Injection-Ejection Blocking [previous slide]
Intra-dimentional Blocking (Torus Network) Virtual Channel Flow Control▪ Circuit Switching
terminate-on-timeout packet
Simulation Parameters
POINTS Simulator Based on OMNET++
36-core CMP 6x6 planar
Chip size: 20 x 20 mm Uniform Traffic 3 Cases
Deadlock Message Size Optimization Increasing Path Diversity
2
Message Size Optimization
Long path-setup latency Nonoseconds
Super fast transmission
Overhead Ratio:
Message Size Optimization (cont.)
Message Duration: 50ns Message Size: 2KB Suitable for
DMA Trans
Increasing Path Diversity
PD=2 Less Hardware Less Overhead
Difference
Q & A ?
Thanks !