Instruction scheduling in Compiler Design - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is instruction scheduling in compiler design?

Instruction scheduling is a compiler optimization technique that rearranges the order of instructions to improve performance by reducing delays caused by hardware constraints like pipeline stalls.

beginner

Why is instruction scheduling important for modern processors?

It helps to keep the processor's pipeline busy by avoiding stalls and hazards, which leads to faster execution of programs.

intermediate

What are hazards that instruction scheduling tries to avoid?

Hazards are situations like data hazards, control hazards, and structural hazards that can cause delays or incorrect execution if instructions are not properly ordered.

intermediate

How does instruction scheduling relate to instruction-level parallelism (ILP)?

Instruction scheduling increases ILP by rearranging instructions so that independent instructions can execute in parallel without waiting for others to finish.

intermediate

Name two types of instruction scheduling techniques.

Static scheduling, done by the compiler before runtime, and dynamic scheduling, done by the processor during execution.

What is the main goal of instruction scheduling?

A To add more instructions to the code

B To increase the size of the program

C To slow down the processor

D To rearrange instructions to reduce pipeline stalls

Instruction scheduling aims to reorder instructions to minimize delays and keep the processor pipeline busy.

Which hazard does instruction scheduling help to avoid?

A Power hazard

B Memory leak

C Data hazard

D Syntax error

Instruction scheduling helps avoid data hazards by reordering instructions to prevent conflicts over data usage.

Static instruction scheduling is performed by:

A The compiler before the program runs

B The processor during execution

C The operating system

D The user manually

Static scheduling is done by the compiler at compile time to optimize instruction order.

Instruction-level parallelism means:

A Running programs on multiple computers

B Executing multiple instructions at the same time

C Writing instructions in parallel lines

D Using multiple programming languages

Instruction-level parallelism allows independent instructions to run simultaneously to improve performance.

Which of the following is NOT a hazard addressed by instruction scheduling?

A Network hazard

B Structural hazard

C Data hazard

D Control hazard

Network hazards are unrelated to instruction scheduling and processor pipelines.

Explain what instruction scheduling is and why it is used in compilers.

Think about how changing the order of instructions can help the processor run faster.

Describe the difference between static and dynamic instruction scheduling.

Consider who decides the instruction order and when.