Pipelining

• What is the main purpose of pipelining in a processor?

  To improve efficiency
• How does the analogy of writing invites illustrate the concept of pipelining?

  • One person writing all invites is inefficient.
  • With help, tasks can be done simultaneously.
  • Similar to how processors fetch, decode, and execute instructions concurrently.
• What happens in the inefficient method of sending invites?

  One person writes all invites, places them in envelopes, attaches stamps, and addresses them sequentially.
• How does the efficient method of sending invites improve the process?

  By allowing friends to perform different tasks simultaneously, such as writing, stamping, and addressing invites.
• What is the fetch-decode-execute cycle in a processor?

  It is the process where the processor fetches an instruction, decodes it, and then executes it.
• How does pipelining improve the fetch-decode-execute cycle?

  It allows the next instruction to be fetched while the processor is executing or decoding previous instructions.
• What happens to the ALU during pipelining?

  The ALU can perform arithmetic or logic operations while the next instruction is being fetched.
• What are the two types of pipelines in processor pipelining?

  • Instruction Pipeline: Stages an instruction must move through.
  • Arithmetic Pipeline: Parts of an arithmetic operation that can be overlapped.
• Why is pipelining common in today's processors?

  It allows multiple instructions to be executed simultaneously.
• How does pipelining work with pseudo code in a processor?

  1. Fetch instruction one.

  2. Decode instruction one while fetching instruction two.

  3. Execute instruction one while decoding instruction two and fetching instruction three.

  4. Continue this process for subsequent instructions.
• What potential problem arises during pipelining with branching instructions?

  Branching may require the processor to jump to a different instruction, causing previously fetched instructions to be flushed.
• What does flushing the pipe mean in the context of pipelining?

  It means removing instructions that are no longer needed due to a branch in the program.
• How does branching affect the efficiency of pipelining?

  Programs with many branching instructions may not benefit much from pipelining.
• What is a key question to consider regarding processor speed after learning about pipelining?


  How can the speed of a processor be increased further?