Avoid sorting in hash map stable hashing by Kobzol · Pull Request #91837 · rust-...
source link: https://github.com/rust-lang/rust/pull/91837
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Suggested by @the8472 here. I hope that I understood it right, I replaced the sort with modular multiplication, which should be commutative.
Can I ask for a perf. run? However, locally it didn't help at all. Creating the StableHasher all over again is probably slowing it down quite a lot. And using FxHasher is not straightforward, because the keys and values only implement HashStable (and probably they shouldn't be just hashed via Hash anyway for it to actually be stable).
Maybe the StableHash interface could be changed somehow to better suppor these scenarios where the hasher is short-lived. Or the StableHasher implementation could have variants with e.g. a shorter buffer for these scenarios.
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