Bypass Network
A way to speculatively pass execution results to waiting instructions directly without writing them to the Merged Register File or Reorder Buffer . This can save cycles.
Tradeoff:
- It can increase instructions per cycle (IPC)
- But also increases cycle time and power consumption.
Figure 1: Without bypass network
Figure 2: With bypass network
Clustering #
- Bypassing introduces very complex networks
- Solution: cluster FUs into clusters and only create bypass networks inside the clusters