poor scaling of `functools.lru_cache`
Open
Nobody has claimed this yet.
3.15
performance
topic-free-threading
- Dominant language
- Python
- Stars
- 77.2k
- Forks
- 35.9k
- PR merge metrics
- PR metrics pending
Description
functools.lru_cache currently scales poorly in free-threading because of reference counting contention on the object. The underlying function has deferred reference counting enabled but the cache object itself needs deferred reference counting as well to perform well in free-threading.
Linked PRs
- gh-142632
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reviewing the functools.lru_cache implementation and linked PR gh-142632, then examine how free-threading affects reference counting for the cache object. Done means the cache scales better under free-threading while preserving existing lru_cache behavior and tests.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- performance
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 25/100