Low Power Flitwise Routing in an Unidirectional Torus with Minimal - PowerPoint PPT Presentation

Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering J¨ org Mische and Theo Ungerer Systems and Networking Department of Computer Science University of Augsburg NoCArc Workshop Vancouver, Canada, 2012-12-01 J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 1

Motivation On-chip Networks for Embedded Systems ◮ Connect small cores by a NoC ◮ Routers must be small and power-efficient, too Alternative Router Design ◮ Reduce area and power consumption ◮ Reduce complexity of router ◮ Provide acceptable network throughput J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 2

Outline Router Microarchitecture Routing Algorithm Evaluation of Throughput and Costs J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 3

Conventional Router in a Mesh J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 4

Conventional Router Architecture J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 5

Conventional Router Architecture mesh J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 5

Conventional Router Architecture mesh ◮ 4+1 input ports, 4+1 output ports J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 5

Conventional Router Architecture mesh ◮ 4+1 input ports, 4+1 output ports ◮ 5x5 crossbar J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 5

Conventional Router Architecture mesh ◮ 4+1 input ports, 4+1 output ports ◮ 5x5 crossbar wormhole routing J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 5

Conventional Router Architecture mesh ◮ 4+1 input ports, 4+1 output ports ◮ 5x5 crossbar wormhole routing ◮ input or output buffers J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 5

Conventional Router Architecture mesh ◮ 4+1 input ports, 4+1 output ports ◮ 5x5 crossbar wormhole routing ◮ input or output buffers ◮ buffers for virtual channels J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 5

Conventional Router Architecture mesh ◮ 4+1 input ports, 4+1 output ports ◮ 5x5 crossbar wormhole routing ◮ input or output buffers ◮ buffers for virtual channels ◮ pipelined logic J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 5

Unidirectional Torus comparision with mesh bidirectional 1 × bandwith o 0 . 5 × #ports/links + 2 × link length - 1 × link area o 0 . 5 × link capacity - J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 6

Folded Unidirectional Torus J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 7

Reducing Router Complexity J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 8

Reducing Router Complexity unidirectional torus J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 8

Reducing Router Complexity unidirectional torus ◮ 2+1 input ports, 2+1 output ports J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 8

Reducing Router Complexity unidirectional torus ◮ 2+1 input ports, 2+1 output ports ◮ 3x3 crossbar J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 8

Reducing Router Complexity unidirectional torus ◮ 2+1 input ports, 2+1 output ports ◮ 3x3 crossbar semi-bufferless routing J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 8

Reducing Router Complexity unidirectional torus ◮ 2+1 input ports, 2+1 output ports ◮ 3x3 crossbar semi-bufferless routing ◮ 1 buffer J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 8

Reducing Router Complexity unidirectional torus ◮ 2+1 input ports, 2+1 output ports ◮ 3x3 crossbar semi-bufferless routing ◮ 1 buffer ◮ simplified routing logic J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 8

Paternoster Routing ◮ constantly rotating x-rings J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot ◮ x transport J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot ◮ x transport ◮ turn to corner buffer J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot ◮ x transport ◮ turn to corner buffer ◮ enter y-ring if empty slot J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot ◮ x transport ◮ turn to corner buffer ◮ enter y-ring if empty slot J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot ◮ x transport ◮ turn to corner buffer ◮ enter y-ring if empty slot ◮ y transport J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot ◮ x transport ◮ turn to corner buffer ◮ enter y-ring if empty slot ◮ y transport J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9

Paternoster Routing ◮ constantly rotating x-rings ◮ constantly rotating y-rings ◮ enter x-ring if empty slot ◮ x transport ◮ turn to corner buffer ◮ enter y-ring if empty slot ◮ y transport J¨ org Mische / Low Power Flitwise Routing in an Unidirectional Torus with Minimal Buffering 2012-12-01 9