12 / 18 Pipelining & Execution

Pipeline Stall: Throughput vs Latency

A pipeline stall (bubble) is inserted due to a data hazard. What does this affect?

A

Neither: the hardware hides stalls completely through forwarding

B

Only latency: the stalled instruction takes longer but throughput is unchanged

C

Only throughput: the stalled instruction finishes at the same time but fewer instructions complete per cycle

D

Both: the stalled instruction's latency increases and overall throughput drops because a pipeline stage sits idle for a cycle