mem-ruby: Implementation of StashOnceShared/StashOnceUnique

[tsyw]

Hi everyone,

Currently, StashOncexxx hints are ignored in CHI-cache. I'm working on the implementation of the StashOnceShared/StashOnceUnique flows in gem5 to provide the full transitions and now I have a couple of questions:

Testing CHI Protocol

• Currently, I'm using the ./configs/example/ruby_xxx_test.py scripts for testing. While these provide random or directed tests, I'm wondering if there's any formal verification infrastructure specifically for SLICC state machines?
• Additionally, these existing tests don't cover Stash hints, so I'll need to add new test cases that specifically target this functionality.

Contribution Process

• Since coherence protocols can be quite complex, should I prepare any additional documentation to accompany my changes?

I'd appreciate any guidance or insights you can provide.

You can find my current work here. basic flows are implemented, testing is the next step: https://github.com/tsyw/gem5/commits/chi_flow_stashonce/

Thanks in advance!

[powerjg]

I'm excited that you're working on this. It would be a great contribution to the community! @giactra for visibility.

any formal verification infrastructure specifically for SLICC state machines?

Not for any of the publicly available protocols. (I wish there was!)

I'll need to add new test cases that specifically target this functionality.

Makes sense. Looking forward to it!

should I prepare any additional documentation to accompany my changes?

As much high-level information as possible to help review would be good. E.g., design document kind of writing. That said, since you're touching hints and not "functional" parts of the protocol the bar is lower.

[kiriakaras]

Hi @tsyw , thanks for your contribution. What is the state of your branch? Is it in a state that can be used, or are there still unresolved issues? Many thanks again!

[tsyw]

Hi @tsyw , thanks for your contribution. What is the state of your branch? Is it in a state that can be used, or are there still unresolved issues? Many thanks again!

Hi, currently the branch can be used and is ready to be reviewed.

[tsyw]

#2975