On Thu, 12 Sep 2024 11:28:20 GMT, Eirik Bjørsnøs <eir...@openjdk.org> wrote:
>> Please review this PR which speeds up `ZipFile.getZipEntry` by removing >> slash-checking logic which is already taking place during lookup in >> `ZipFile.Source.getEntryPos`. >> >> `ZipFile.Source.getEntryPos` includes logic to match a lookup for "name" >> against a directory entry "name/" (with a trailing slash). However, only the >> CEN position is currently returned, so `ZipFile.getZipEntry` needs to >> re-read the name from the CEN and determine if a trailing slash needs to be >> appended to the name of the returned `ZipEntry`. >> >> By letting `ZipFile.Source.getEntryPos` return the resolved name along with >> the CEN position (in a new record `EntryPos`), `ZipFile.getZipEntry` can now >> instead use the already resolved name. >> >> Since `ZipFile.getZipEntry` now has the name, CEN header fields can now be >> read in bulk, separate from the allocation of the `ZipEntry`. This >> reordering is unlocked by the other changes in this PR and can alone explain >> a lot of the performance gains, probably because of better cache use. >> >> This results in a nice ~18% speedup in the `ZipFileGetEntry.getEntryHit` >> micro: >> >> Baseline: >> >> >> Benchmark (size) Mode Cnt Score Error Units >> ZipFileGetEntry.getEntryHit 512 avgt 15 63.713 ? 2.645 ns/op >> ZipFileGetEntry.getEntryHit 1024 avgt 15 67.405 ? 1.474 ns/op >> >> >> PR: >> >> >> Benchmark (size) Mode Cnt Score Error Units >> ZipFileGetEntry.getEntryHit 512 avgt 15 52.027 ? 2.669 ns/op >> ZipFileGetEntry.getEntryHit 1024 avgt 15 55.211 ? 1.169 ns/op >> >> The changes in this PR makes `UTF8ZipCoder.compare` the only caller of >> `ZipCoder.hasTrailingSlash`, so this method is made private and the >> implementation in the base class retired. >> >> This purely a cleanup and optimization PR, no functional tests are changed >> or added. > > Eirik Bjørsnøs has updated the pull request incrementally with one additional > commit since the last revision: > > Add comment where getEntry calls Source::getEntryPos LGTM ------------- Marked as reviewed by redestad (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/20939#pullrequestreview-2300253644
