Routing¶

The second aspect of the network is how the routing is performed in FlooNoC, which is where FlooGen comes into play. A lot of of the routing information is quite cumbersome to define and error-prone to do by hand. FlooGen allows you to define the routing in a high-level way, and it will generate the low-level routing information for you. The basic information you need to provide is:

routing:
  route_algo: "XY"
  use_id_table: true

The routing section of a configuration file.

This holds only what a configuration declares. The widths and address maps that Network.gen_routing_info() derives from the elaborated graph live on Routing, which extends this class, so that a configuration cannot set them and the two are not confused for one another.

Attributes:

Name	Type	Description
`route_algo`	`RouteAlgo`	This determines the routing algorithm to use. You can find more information about the different routing algorithms in the routing algorithms documentation.
`use_id_table`	`bool`	A boolean flag indicating that if set to `true`, a system address table will be generated in the package which is used to translate system addresses to endpoint IDs or coordinates. This is always used in table-based routing and can be used in `XYRouting` to translate system addresses to XY-coordinates. If `XYRouting` is used and this field is set to `false`, the XY coordinates are automatically derived as address offsets. This is much simpler but requires that all endpoint addresses are contiguous and of the same size.
`rob_idx_bits`	`int`	The number of bits to allocate for the `rob_idx` field in the packet header. This is only relevant if reordering buffers are used in the network.
`collective`	`CollectiveCfg`	Collective operation configuration (multicast, barrier, reduction).

Reference¶

Beyond what you configure above, FlooGen derives a great deal more from the elaborated network: the system address map (sam), the coordinate and route widths, the endpoint count, and so on. Those live on Routing, which extends RoutingDesc and is built by Network.gen_routing_info(). They are not configuration and cannot be set in a configuration file.

A RoutingDesc together with everything Network.gen_routing_info() derives.

Constructed once the graph is elaborated, so sam, addr_width and the endpoint counts are always present. The remaining widths stay optional because which of them exists is decided by route_algo; render_* raises if one is read that the configured algorithm never produces.

The full API reference of the routing model, including methods and other routing-related classes (e.g., RouteMap, RouteTable), can be found in the Routing Reference.