Handling Hazards 2 - Pipeline and Vector Processing - Computer Organization and Architecture

TL;DR

Learn how data hazards are managed in CPUs to ensure correct program execution with minimal stall cycles.

Transcript

hello everyone in the previous session we have seen how the structural hazard is going to be handled in this session we will understand how the data hazard is going to be dealt with let us understand how to handle the data but before you handle the data hazards you need to consider a few factors let us stay focused you know that data hazard will oc... Read More

Key Insights

• ☣️ Data hazards in CPUs occur due to dependencies between instructions in a pipeline.
• 🏍️ Hardware interlock identifies dependencies but may not reduce stall cycles in CPU pipelines.
• 🏍️ Operand forwarding forwards output directly to the input, reducing stall cycles to one.

Questions & Answers

Q: What are data hazards in a CPU pipeline?

Data hazards in a CPU pipeline occur when instructions have dependencies, requiring stall cycles to separate them for correct program execution.

Q: How is hardware interlock used to handle data hazards?

Hardware interlock in a CPU identifies dependencies between instructions and separates them for correct program execution, though it may not reduce stall cycles.

Q: What is operand forwarding and how does it reduce stall cycles?

Operand forwarding in a CPU pipeline forwards output directly to the input of the next instruction, reducing stall cycles to just one for correct program execution.

Q: Why is ignoring dependencies not a feasible method to handle data hazards?

Ignoring dependencies in a CPU pipeline leads to incorrect program outcomes, defeating the purpose of program execution in a computer system.

Summary & Key Takeaways

• Data hazards occur due to dependencies between instructions in a CPU pipeline, leading to stall cycles.

• To handle data hazards, methods like hardware interlock, operand forwarding, and delayed load are used.

• Hardware interlock identifies dependencies, operand forwarding reduces stall cycles to one, ensuring correct program execution.