What you'll learn

DRAM must refresh or it loses data. Refresh steals bandwidth. Scheduler policy determines how much.

• Distinguish tREFI (average refresh-command interval), the full refresh window and tRFC (refresh recovery time).

• Distinguish a row hit, an idle-bank access and a row conflict from the command sequence each requires.

• Measure useful bytes per interval; account for overlapping scheduling, refresh and turnaround effects without double-counting.

Connection

Applies bandwidth budgeting specifically to DRAM scheduler behavior.

Key diagram

Refresh occupancy is one part of service

Study this topic

1. Concepts — rules and mental models

2. Integration — system contracts

3. Debug — trace the first divergence

4. Interview — explain and defend your answer