Virtual Channels and Flow Control

 

Virtual channels enables the blocked packet to progress.

• Select physical output channel.
• Find next free virtual channel on physical channel.
• If no free virtual channel then block.
• Transmit packet along virtual channel.
• Release virtual channel.

Experiments on 2-ary butterflies with 16 flit buffers. Throughput of for 1 virtual channel rising to for 16 virtual channels.

• Structured Buffer Pool in Wormhole Routing