On Fri, 18 Oct 2024 12:08:08 GMT, Eirik Bjørsnøs <eir...@openjdk.org> wrote:
>> There are a few possible strategies for avoiding that additional parse, >> since the effect we're getting at here is to have a quick filter to avoid >> pointless lookups and not necessarily an exact mapping. >> >> One is to store the `checkedHash` rather than the full `String`. This gets >> `openCloseZipFile` down to ~910000 ns/op. (`checkedHash` very hot in >> profiles). There's still a chance for redundant lookups on hash collisions, >> but this should be rare. >> >> Another is to store a `BitSet` per name length. This gets `ZipFileOpen` down >> to baseline level (~670000 ns/op), but increases chance of having to do >> redundant lookups a lot. >> >> Both also improves footprint (not keeping each versioned entry `String` in >> memory would be nice). > >> One is to store the `checkedHash` rather than the full `String`. This gets >> `openCloseZipFile` down to ~910000 ns/op. (`checkedHash` very hot in >> profiles). There's still a chance for redundant lookups on hash collisions, >> but this should be rare. > > Seems like a resonable trade-off. Could you take a look at the latest > 771488e and see if that represents your suggestion here? Yes, 771488e matches my quick experiment (sans some cleanups you've made). I agree this variant makes for a reasonable trade-off. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21489#discussion_r1806420039
