Lesson 6: Cache Coherence

• discussion thread

On readings: Recommended background readings are marked with (^) above. Optional historical or fun readings are marked with (*). If you feel confortable with the topic already, you may skip these readings.

Notes

See my slides on Canvas

Take a look at this coherence protocol visualization. This was generated by Claude Code in about 30min. I haven't verified the protocol correctness, so take it with a big grain of salt, but it should give you a basic idea of how coherence traffic propagates on the coherence network (bus).

Here is a description of the Alpha 21064, the predecessor of the core arch referenced in the paper.

Here are a few other influential papers/books written by Luiz Barroso:

• Failure Trends in a Large Disk Drive Population
• The Case for Energy-Proportional Computing
• Attack of the Killer Microseconds
• The Tail at Scale
• The Datacenter as a Computer
• Availability in Globally Distributed Storage Systems
• Bluetooth Contact Tracing for COVID

RIP Luiz.

Tasks

Mostly the same as previous times.

• Do the background reading and read the paper for next week.
• Ask any questions about the course structure or content in this paper's discussion topic.
• Pick a paper from the schedule whose discussion you want to lead. Claim it by opening a pull request that modifies content.toml to fill in your name on one of the leader = "TBD" lines.