Flow control using a local event ring in an island-based network flow processor

Abstract

An island-based network flow processor (IB-NFP) integrated circuit includes islands organized in rows. A configurable mesh event bus extends through the islands and is configured to form a local event ring. The configurable mesh event bus is configured with configuration information received via a configurable mesh control bus. The local event ring involves event ring circuits and event ring segments. In one example, a packet is received onto a first island. If an amount of a processing resource (for example, memory buffer space) available to the first island is below a threshold, then an event packet is communicated from the first island to a second island via the local event ring. In response, the second island causes a third island to communicate via a command/push/pull data bus with the first island, thereby increasing the amount of the processing resource available to the first island for handing incoming packets.