What This Document Is
This document represents Lecture 11 from Computer Systems Architecture (COMSCI M151B) at UCLA. It’s a focused exploration of pipeline hazards – specifically, control hazards – within the context of computer processor design. This lecture delves into the challenges that arise when the sequential instruction flow of a program is disrupted by branching or jumps in the code, and how these disruptions impact performance. It examines both hardware and software approaches to mitigating these issues.
Why This Document Matters
This lecture is crucial for students aiming for a deep understanding of how modern computer processors actually *work*. It’s particularly valuable for those interested in compiler design, performance optimization, or hardware engineering. If you’re struggling to reconcile theoretical processor models with real-world performance limitations, or if you need a solid foundation for advanced topics like out-of-order execution, this material will be highly beneficial. It’s best reviewed *after* gaining a firm grasp of basic pipelining concepts.
Topics Covered
* The fundamental causes of control hazards in pipelined processors.
* The impact of branches, jumps, and procedure calls on pipeline efficiency.
* Strategies for dealing with control hazards, including stalling and prediction.
* A comparison of static and dynamic optimization techniques.
* The trade-offs between accuracy and penalty in branch prediction.
* The role of hardware in detecting and resolving branch outcomes.
What This Document Provides
* A detailed examination of the performance implications of pipeline stalls.
* An overview of different branch prediction schemes, from simple static approaches to more complex dynamic methods.
* Insights into how branch prediction accuracy affects overall system performance.
* A discussion of the challenges associated with implementing effective branch prediction in deeper pipelines.
* A foundational understanding of the complexities involved in maintaining program correctness while maximizing processor speed.
