Question

A five-stage pipeline has stage delays of 150, 120, 150, 160 and 140 nanoseconds.
The register delay between stages is 5 nanoseconds. The total time to execute 100 independent instructions is \(\underline{\hspace{2cm}}\) nanoseconds.

Hint:

Pipeline execution time depends on the slowest stage, not the sum of all stage delays.

Answer 1

Correct Answer: 17160

The clock cycle time of a pipelined processor is determined by the slowest pipeline stage plus the pipeline register overhead.

Step 1: Determine clock cycle time.
Given: \[ \text{Maximum stage delay} = 160 \text{ ns} \] \[ \text{Pipeline register delay} = 5 \text{ ns} \] Hence, the clock cycle time is: \[ \text{Clock cycle time} = 160 + 5 = 165 \text{ ns} \]

Step 2: Calculate total number of clock cycles.
For a pipeline with 5 stages, the total number of cycles required to execute 100 instructions is: \[ \text{Cycles} = n + k - 1 = 100 + 5 - 1 = 104 \]

Step 3: Compute total execution time.
\[ \text{Total execution time} = 104 \times 165 = 17160 \text{ ns} \]

Final Answer:
\[ \boxed{17160} \]