220.127.116.11. Handshaking Between Clusters
By default, the handshaking protocol between clusters is a simple stall/valid protocol. Data from the upstream cluster is consumed when the stall signal is low and the valid signal is high.
If the distance across the FPGA between these two clusters is large, handshaking may become the critical path that affects peak fMAX. in the design
To improve these cases, the Intel® HLS Compiler can add pipelining registers to the stall/valid protocol to ease the critical path and improve fMAX. This enhanced handshaking protocol is called hyper-optimized handshaking.
The following timing diagram illustrates an example of upstream cluster 1 and downstream cluster 2 with two pipelining registers inserted in-between: