Congestion control and QoS in NoC by regulating the injection traffic

Patent metadata

Field	Value
Publication number	US-9571402-B2
Application number	US-201313886794-A
Country	US
Kind code	B2
Filing date	May 3, 2013
Priority date	May 3, 2013
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

Systems and methods described herein are directed to solutions for NoC interconnects that provide congestion avoidance and end-to-end uniform and weighted-fair allocation of resource bandwidths among various contenders in a mesh or torus interconnect. The example implementations are fully distributed and involve using explicit congestion notification messages or local congestion identification for congestion detection. Based on the congestion level detected, the injection rates of traffic at various agents are regulated that avoids congestion and also provides end-to-end QoS. Alternative example implementations may also utilize end-to-end credit based flow control between communicating agents for resource and bandwidth allocation of the destination between the contending sources. The resource allocation is performed so that both the weighted and strict bandwidth allocation QoS policies are satisfied.

First claim

What is claimed is:

1. A Network on Chip (NoC) comprising a first node and a second node, the NoC configured to:
receive, at one of the first node and the second node, an instruction based on a command signal from the other of the first node and the second node, and a computed level of congestion based on a Quality of Service (QoS) metric indicative of traffic congestion, the computed level of congestion is computed at the other of the first node and the second node, and
wherein the one of the first node and the second node adjusts, based on the instruction, an allocation of traffic bandwidth of the one of the first node and the second node,
wherein the one of the first node and the second node is a source agent configured to generate a message for a destination agent and transmit the message to a router of the NoC, and the other of the first node and the second node is the destination agent of the message;
wherein the one of the first node and the second node adjusts the allocation of traffic bandwidth based on a buffer allocation issued to the one of the first node and the second node from the other of first node and the second node.

2. The NoC of claim 1 , wherein the QoS metric comprises at least one of a round trip time of a request message to a response message, and backpressure experienced by the one of the first node and the second node.

3. The NoC of claim 1 , wherein the command signal is a notification message indicative of a degree of congestion.

4. The NoC of claim 1 , wherein the one of the first node and the second node adjusts, for itself, the allocation of traffic bandwidth by a determination of a transmission rate at the one of the first node and the second node and an allocation of traffic bandwidth based on the determined transmission rate.

5. A method for a Network on Chip (NoC) comprising a first node and a second node, the method comprising:
receiving, at one of the first node and the second node, an instruction based on a command signal from the other of the first node and the second node, and a computed level of congestion based on a Quality of Service (QoS) metric indicative of traffic congestion, the computed level of congestion is computed at the other of the first node and the second node, and
wherein the one of the first node and the second node adjusts, based on the instruction, an allocation of traffic bandwidth of the one of the first node and the second node,
wherein the one of the first node and the second node is a source agent configured to generate a message for a destination agent and transmit the message to a router of the NoC, and the other of the first node and the second node is the destination agent of the message;
wherein the one of the first node and the second node adjusts the allocation of traffic bandwidth based on a buffer allocation issued to the one of the first node and the second node from the other of first node and the second node.

6. The method of claim 5 , wherein the QoS metric comprises at least one of a round trip time of a request message to a response message, and backpressure experienced by the one of the first node and the second node.

7. The method of claim 5 , wherein the command signal is a notification message indicative of a degree of congestion.

8. The method of claim 5 , wherein the one of the first node and the second node adjusts, for itself, the allocation of traffic bandwidth by a determination of a transmission rate at the one of the first node and the second node and an allocation of traffic bandwidth based on the determined transmission rate.

9. A non-transitory computer readable medium, storing instructions for executing a process for a Network on Chip (NoC) comprising a first node and a second node, the instructions comprising:
receiving, at one of the first node and the second node, an instruction based on a command signal from the other of the first node and the second node, and a computed level of congestion based on a Quality of Service (QoS) metric indicative of traffic congestion, the computed level of congestion is computed at the other of the first node and the second node, and
wherein the one of the first node and the second node adjusts, based on the instruction, an allocation of traffic bandwidth of the one of the first node and the second node,
wherein the one of the first node and the second node is a source agent configured to generate a message for a destination agent and transmit the message to a router of the NoC, and the other of the first node and the second node is the destination agent of the message;
wherein the one of the first node and the second node adjusts the allocation of traffic bandwidth based on a buffer allocation issued to the one of the first node and the second node from the other of first node and the second node.

10. The non-transitory computer readable medium of claim 9 , wherein the QoS metric comprises at least one of a round trip time of a request message to a response message, and backpressure experienced by the one of the first node and the second node.

11. The non-transitory computer readable medium of claim 9 , wherein the command signal is a notification message indicative of a degree of congestion.

12. The non-transitory computer readable medium of claim 9 , wherein the one of the first node and the second node adjusts, for itself, the allocation of traffic bandwidth by a determination of a transmission rate at the one of the first node and the second node and an allocation of traffic bandwidth based on the determined transmission rate.

Assignees

• Netspeed Systems

Inventors

• Kumar Sailesh
• Norige Eric

Classifications

• H04L47/18 Primary

  End to end · CPC title

• H04L47/24

  Traffic characterised by specific attributes, e.g. priority or QoS · CPC title

• H04L47/30

  in combination with information about buffer occupancy at either end or at transit nodes · CPC title

• H04L47/39

  Credit based · CPC title