Under Amdahl's fixed-workload assumptions, which part keeps its duration when more cores are added?

• The serial part of the workload
• The equally shared parallel part
• Every part of the entire workload

For fixed work with an unchanged serial fraction of 0.1, what is Amdahl's ideal limiting speedup bound?

• Tenfold speedup
• Hundredfold speedup
• Unbounded speedup

Using several cores and using SIMD data lanes are the same execution arrangement.

One instruction applies the same addition operation to eight data elements together. Which arrangement does this describe?

• Eight cores following separate instruction streams
• SIMD data lanes sharing an addition operation
• One core executing eight scalar additions in sequence

A fixed workload is 0.1 serial. Its serial time is unchanged; its parallel part divides equally across nine cores with no overhead. What is the ideal speedup over one core?

Adding cores saves 4 ms of computation but adds 7 ms of coordination and waiting. Why does total time increase?

• The serial fraction must have fallen to zero
• The workload must have become fully independent
• The added costs exceed the computation saving

Knowing that half a workload is parallel is enough to guarantee that buying more cores reduces its actual runtime.

A fixed workload has an unchanged serial fraction of 0.1. The parallel part divides equally across 30 cores with no added overhead. What is the ideal speedup over one core?

• About 30, because all work divides by the core count
• About 7.69, from dividing 1 by the normalized time
• Exactly 10, because finite cores reach the limiting bound