qut : a low-power optical network-on-chip
DESCRIPTION
QuT : A Low-Power Optical Network-on-chip. Parisa Khadem Hamedani Natalie Enright Jerger Shaahin Hessabi. Introduction: Electrical NoC. Electrical NoC Scalability limitation Power Network channel and buffering power Latency. Introduction: Optical NoC. Waveguide Optical Switches. - PowerPoint PPT PresentationTRANSCRIPT
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
QuT: A Low-Power Optical Network-on-chip
Parisa Khadem Hamedani
Natalie Enright Jerger
Shaahin Hessabi
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Introduction: Electrical NoC Electrical NoC
Scalability limitation Power
Network channel and buffering power Latency
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Introduction: Optical NoC Optical NoC
Power is independent of transmission distance Small transmission latency Simple modulation, large data bandwidths (Gbps)
Transmitter
Receiver
Off-chip Laser
Waveguide
Optical Switches
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Introduction: Optical NoC Challenges Optical NoC
Insertion Loss The loss of signal power resulting from the insertion in
an optical path Main factor in the power consumption
Number of Microrings Major source of faults
Number of Wavelengths Wavelength-division multiplexing (WDM) Total power is proportional to the number of
wavelengths
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Introduction: Quarten Topology (QuT)
0
2
1
3
4
6
5
78
10
9
11
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14
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15
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Outline Introduction Quartern Architecture
Data Network Router Microarchitecture
Wavelength assignment All optical switches
QuT WDM Routing Control Network
Methodology Evaluation Conclusion
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Quartern Architecture A new all-optical architecture
Based on passive microring resonators Addressing the optical challenges
Ring-based topology Strategically placed extra links
To reduce the diameter To reduce number of wavelengths
A new deterministic wavelength routing Contention-free network Optimizing optical switches
With an optical control network
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Data Network
Ring links Bidirectional
0
2
1
3
4
6
5
78
10
9
11
12
14
13
15
Cross links Bidirectional Even
Bypass links Unidirectional Emanate from odd nodes
Cross
Bypass
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Router Microarchitecture : Wavelength assignment Each node has:
Dedicated but not unique wavelength Source uses this wavelength
In an N-node QuT N/4 distinct wavelength sets Node i dedicated wavelength set
(i mod N/4)
λ1λ0
λ2
λ3
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QuT WDM Routing : Source is even Distance (Source, Destination):
< N/4 = N/2
Ring links
Source
Destination
0
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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QuT WDM Routing : Source is even Distance (Source, Destination):
>= N/4
Cross links
Source
Destination
0
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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QuT WDM Routing : Source is Odd Distance (Source, Destination):
<= N/4
Ring links
Source
Destination
1
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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QuT WDM Routing : Source is Odd Distance (Source, Destination):
> N/4
Bypass links
Source
Destination
1
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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QuT WDM Routing: example
0
8
Source: N0Destination: N8
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Example: Switch at N0
Ring (Left)
Bypass (Left)
Cross (Left)
Cross (Right)
Ring (Right)
Bypass (Right)
I1
I2
I3
I401
8
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Example: Switch at N1
0
21
8
Ring (Left)
Ring (Right)
Bypass (Left)
Bypass (Right)
I1
I2
I3
I4
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Example: Switch at N2
0
21
6
8
Ring (Left)
Bypass (Left)
Cross (Left)
Cross (Right)
Ring (Right)
Bypass (Right)
I1
I2
I3
I4
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Example: Switch at N6
0
6
7 8
Ring (Left)
Bypass (Left)
Cross (Left)
Cross (Right)
Ring (Right)
Bypass (Right)
I1
I2
I3
I4
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Example: Switch at N7
0
21
67 8
Ring (Left)
Ring (Right)
Bypass (Left)
Bypass (Right)
I1
I2
I3
I4
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Example: Switch at N8
0
21
6
7 8
Ring (Left)
Bypass (Left)
Cross (Left)
Cross (Right)
Ring (Right)
Bypass (Right)
I1
I2
I3
I4
E
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Router Microarchitecture: All optical switches (Even)
AddμR BypassμR DropμR
Ring (Left)
Bypass (Left)
Cross (Left)
Cross (Right)
Ring (Right)
Bypass (Right)
I1
I2
I3
I4
E
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Router Microarchitecture: All optical switches (Even)
Ring (Left)
Bypass (Left)
Cross (Left)
Cross (Right)
Ring (Right)
Bypass (Right)
I1
I2
I3
I4
E
AddμR
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Router Microarchitecture: All optical switches (Even)
Ring (Left)
Bypass (Left)
Cross (Left)
Cross (Right)
Ring (Right)
Bypass (Right)
I1
I2
I3
I4
E
BypassμR
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Router Microarchitecture: All optical switches (Even)
Ring (Left)
Bypass (Left)
Cross (Left)
Cross (Right)
Ring (Right)
Bypass (Right)
I1
I2
I3
I4
E
DropμR
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Router Microarchitecture: All optical switches (Odd)
Ring (Left)
Ring (Right)
Bypass (Left)
Bypass (Right)
I1
I2
I3
I4
E
AddμR CrossμR DropμR
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Router Microarchitecture: All optical switches (Odd)
Ring (Left)
Ring (Right)
Bypass (Left)
Bypass (Right)
I1
I2
I3
I4
E
AddμR DropμR
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Router Microarchitecture: All optical switches (Odd)
Ring (Left)
Ring (Right)
Bypass (Left)
Bypass (Right)
I1
I2
I3
I4
E
CrossμR
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Control Network Multiple-Writer Single-Reader bus
Multiple waveguides Control Packets
Request, ACK, NACK Small size: 6 bits
Each source node has a dedicated wavelength In an N-node QuT
N/16 waveguides N wavelengths
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Methodology Phoenixsim
An event-driven simulator Based on OMNet++
64 and 128-node QuT compared against
Topology Number of Wavelength
s
Control Network
λ-router N -Optical Spidergon:
Ring-basedN/2 Optical
Corona: Optical crossbar 8 Slot-token-ring
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Outline Introduction Quartern Architecture Methodology Evaluation
Delay Power Energy Throughput Area
Conclusion
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Evaluation Constant optical bandwidth for all-optical
NoCs Each node has 8 distinct wavelengths
Data stream is modulated on 8 wavelengths assigned to the destination
Die size: 225 mm Packet size: 256 bits 10Gb/s modulator and detector Synthetic traffic patterns:
Random, Bitreverse, Neighbor, Tornado and Hotspot-30%
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Delay: Packet latency (cycle)
Random Neighbor Tornado Bitreverse05
101520253035
QuT
Spider
Corona
128-node:
Offered Load = 0.5
Waiting time in a processor’s output bufferThe delay of modulating the packet
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Power (W)
QuT & CN Spidergon & CN
Corona & CN
λ-router0
5
10
15
20
25
64-node128-node
75.18
Small Insertion loss, Small number of required wavelengths,
Small number of microrings
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Energy-per-bit (pJ)
0
40
80
120
160
200
240
280
QuT
Spidergon
Corona
λ-router
128-node:
Lower power dissipationSmaller average optical path delay
At the saturation point, a small fraction of energy-per-bit is related to data network
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Normalized Throughput-per-watt
0.00.20.40.60.81.0
QuTSpi-dergonCoronaλ-router
0.00.51.01.52.02.5
QuTSpidergonCoronaλ-router
128-node:
64-node:
Better throughput-per-watt, when the network size increases
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Normalized Area
64-node 128-node0
0.5
1
1.5
2
2.5
3
QuT & CN
Spidergon & CN
λ-Router
Corona & CN
154%
44%
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Conclusion Considering optical challenges
Insertion loss Number of microrings Number of wavelengths
Topology Insertion Loss
Number of Wavelengt
hs
Number of Microrings
Control Network
QuT Small N/4 Small Optical
λ-router Large N Largest -
Spidergon Smallest N/2 Large Optical
Corona Largest 8 Smallest Slot-token-ring
Consuming Less power and Energy: Scales better than state-of-art
proposals
Khadem Hamedani et al., QuT: A Low Power Optical Network-on-Chip
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Thank you for your attention!Question?