jpountz opened a new pull request, #14996: URL: https://github.com/apache/lucene/pull/14996
Lucene has call sites of `Bits#get` that are more polymorphic than they should because they sometimes receive a `FixedBitSet` as `Bits`, and sometimes a `FixedBits` (the return type of `FixedBitSet#asReadOnlyBits`). This makes some call sites bimorphic when they could be monomorphic, of polymorphic when they could be bimorphic (e.g. if `SparseFixedBitSet` also get used). Given how polymorphism affects performance, I would like to fix this performance trap. One idea would be to make `BitSet` no longer implement `Bits`, ie. you could no longer pass a `FixedBitSet` when `Bits` are expected, you would need to pass the result of `FixedBitSet#asReadOnlyBits`. This is what this PR does. I had to move/copy some APIs around between `Bits`, `BitSet` and `FixedBitSet` to make it work, but it's not as invasive as I initially worried. The API change is a 11.0 change, but we could backport the bits that reduce polymorphism to 10.x, ie. making sure to pass the result of `FixedBitSet#asReadOnlyBits` rather than the `FixedBitSet` directly when `Bits` are expected. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
