NoC Link¶

NocLink¶

This file defines the NocLink class.

Overview¶

The NocLink represents a connection between two routers in the NoC. The NocLink acts as edges in the NoC and can be used to traverse between routers.The NocLinks are created based on the user provided topology information in the arch file. The NocLink contains the following information:

The source router and destination router the link connects
The bandwidth usage of the link. When a link is used within a traffic flow (communication between two routers), each link in the communication path needs to support a predefined bandwidth of the flow. Every time a link is used in a flow, its bandwidth usage increases based on the bandwidth needed by this link. This is useful to track as it can indicate when a link is being overused (the bandwidth usage exceeds the links supported capability).

Example:

----------                       ----------
/        /        link           /        /
/ router / --------------------->/ router /
/   a    /                       /   b    /
/        /                       /        /
/--------/                       /--------/

In the example above the links source router would be router a and the sink router would be router b.

class NocLink¶

#include <noc_link.h>

Public Functions

NocLink(NocLinkId link_id, NocRouterId source_router, NocRouterId sink_router, double bw, double lat)¶

NocRouterId get_source_router() const¶

Provides the id of the router that has this link as an outgoing edge.

Returns:: A unique id (NocRouterId) that identifies the source router of the link

NocRouterId get_sink_router() const¶

Provides the id of the router that has this link as an incoming edge.

Returns:: A unique id (NocRouterId) that identifies the sink router of the link

double get_bandwidth() const¶

Returns the maximum bandwidth that the link can carry without congestion.

Returns:: A numeric value of the bandwidth capacity of the link

double get_latency() const¶

Returns the zero-load latency of the link.

Returns:: double Zero-load latency of the link.

NocLinkId get_link_id() const¶

Returns the unique link ID. The ID can be used to index vtr::vector<NoCLinkId, …> instances.

Returns:: The unique ID for the link

void set_source_router(NocRouterId source)¶

Can be used to set the source router of the link to a different router.

Parameters:: source – An identifier representing the router that should be the source of this link

void set_sink_router(NocRouterId sink)¶

Can be used to set the sink router of the link to a different router.

Parameters:: sink – An identifier representing the router that should be the sink of this link

void set_bandwidth(double new_bandwidth)¶

Sets the bandwidth capacity of the link. This function should be used when global NoC data structures are created and populated. The bandwidth capacity is used along with bandwidth_usage to measure congestion.

Parameters:: new_bandwidth – The new value of the bandwidth of the link

operator NocLinkId() const¶

Returns the unique link ID. The ID can be used to index vtr::vector<NoCLinkId, …> instances.

Returns:: The unique ID for the link

Private Members

NocLinkId id¶

NocRouterId source_router¶: The router which uses this link as an outgoing edge

NocRouterId sink_router¶: The router which uses this link as an incoming edge

double bandwidth¶: Represents the maximum bits per second that can be transmitted over the link without causing congestion

double latency¶: The zero-load latency of this link in seconds.