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Q-learning based Congestion-aware Routing Algorithm for On-Chip - - PowerPoint PPT Presentation
Q-learning based Congestion-aware Routing Algorithm for On-Chip - - PowerPoint PPT Presentation
Q-learning based Congestion-aware Routing Algorithm for On-Chip Network Fahime Farahnakian, Masoumeh Ebrahimi, Masoud Daneshtalab, Pasi Liljeberg, and Juha Plosila Department of Information Technology, University of Turku, Finland Email:
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Motivation
A congestion-aware adaptive routing algorithm based
- n the Q-learning for network-on-chip(NoC).
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Related work-(1/2)
Q-learning
- utput of Q-learning ---------> Q-table
q Q-table ü Each time, this algorithm starts with an initial state and reaches a goal state by executing a sequence of actions and receiving rewards.
Q-values ¡ Action Space ¡ Next-State Space ¡ ¡ Current-State Space ¡ ¡ ¡ ¡
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Related work- (2/2 )
Q-routing qy= waiting time in the packet queue of node y δ = transmission delay over the link from node x to y
Q y (z ; d) = the time it would take for node y to send this packet to its destination
via any of node y 's neighbors (z )
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Q-learning based Congestion-aware Algorithm
ü NoC-based adjusted Q-table ü Learning Packet Format ü QCA algorithm
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NoC-based adjusted Q-table
Current router Next Router Output port latency Destination
Node 4 1 3 South West Node 0 Node 4 1
- South
- Node 1
Node 4 1 5 South East Node 2 Node 4 3
- West
- Node 3
Node 4 4
- Local
- Node 4
Node 4 5
- East
- Node 5
Node 4 3 7 West North Node 6 Node 4 7
- North
Node 7 Node 4 5 7 East North Node 8
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Learning Packet
Receiving ¡ Node ¡ID Local ¡Latency Global ¡ Latency Destiantion ¡ Node ¡ID 2 ¡bits 8 ¡bits 4 ¡bits 4 ¡bits
X qy Qy (z,d) d
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QCA algorithm
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Experimental Result
Uniform Random Traffic(Throughput)
Average packet latency Throughput
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Experimental Result
Hotspot Traffic
Average packet latency Throughput
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Hardware Cost
Components Area(mm2) router in QCA method 0.1683 router in DyXY method 0.1503
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