MAKING-A-STOP: A NEW BUFFERLESS
ROUTING ALGORITHM FOR ON-CHIP
NETWORK
Author : Jing Lin, Xiaola Lin, Liang Tang
Publish Journal of parallel and Distributed Computing
OUTLINE
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Some background
• Virtual channel
• wormhole switching
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MAS
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Microarchitecture
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Evaluation
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Simulation results
VIRTUAL CHANNEL
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A channel designation which differs from that of the actual radio channel (or range of
frequencies) on which the signal travels
WORMHOLE SWITCHING
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Large network packets are broken into small pieces called flits (flow control digits). The
first flit, called the header flit holds information about this packet's route (namely the
destination address) and sets up the routing behavior for all subsequent flits associated
with the packet. The head flit is followed by zero or more body flits, containing the actual
pay load of data. The final flit, called the tail flit, performs some book keeping to close the
connection between the two nodes. One thing special about wormhole flow control is the
implementation of virtual channels.
PROBLEM
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buffer routing need more power and area and also
adds the complexity of on-chip network design.
MAKE A STOP
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藉由增設一動態register
來給 flits stop 以取代
buffers 並 減少 deflected
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Arbitration unit
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register array
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switch crossbar
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Router has five input ports and five output ports
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Warm-up period of 100,000 cycles
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10,000 packets are injected per node
TRAFFIC PATTERNS
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OR traffic assumes each node uniformly injects packets to randomly distributed
destinations in the network.
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In TR traffic, the node ( i , j ) only communicates with node ( j , i ) .
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In HS traffic, four hotspot nodes are located at the center of the network. The 80% of
traffic is sent to randomly distributed destinations in the network, while the remaining
traffic is to the hotspot nodes.
LATENCY
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Packet latency is
calculated from the time
when the first flit of
a packet is generated,
to the time when its last
flit is ejected at the
destination, including
source queueing time.
•
the average hop
count per packet as
a function of injected
rate under different
synthetic traffic
patterns before
network saturates.
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The power by flits
traversing through the
channels + the power
needed by the switches in the router.