> Please review this PR which speeds up `JarFile::getEntry` lookup > significantly for multi-release JAR files. > > The changes in this PR are motivated by the following insights: > > * `META-INF/versions/` is sparsely populated. > * Most entries are not versioned > * The number of unique versions for each versioned entry is small > * Many JAR files are 'accidentally' multi-release; they use the feature to > hide `module-info.class` from Java 8. > > Instead of performing one lookup for every version identified in the JAR, > this PR narrows the version search down to only the number of versions found > for the entry being looked up, which will most often be zero. This speeds up > lookup for non-versioned entries, and provides a more targeted search for > versioned entries. > > An alternative approach could be to normalize the hash code to use the > none-versioned name such that versioned and non-versioned names would be > resolved in the same lookup. This was quickly abandoned since the code > changes were intrusive and mixed too many JAR specific concerns into > `ZipFile`. > > Testing: The existing `JarFileGetEntry` benchmark is updated to optionally > test a multi-release JAR file with one versioned entry for > `module-info.class` plus two other versioned class files for two distinct > versions. Performance results in [first comment](#issuecomment-2410901754). > > Running `ZipFileOpen` on a multi-release JAR did not show a significat > difference between this PR and mainline. > > The JAR and ZIP tests are run locally. GHA results green. The `noreg-perf` > label is added in JBS.
Eirik Bjørsnøs has updated the pull request incrementally with one additional commit since the last revision: Use Arrays.sort instead of TreeSet ------------- Changes: - all: https://git.openjdk.org/jdk/pull/21489/files - new: https://git.openjdk.org/jdk/pull/21489/files/b2c900d4..826d78a7 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=21489&range=01 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21489&range=00-01 Stats: 22 lines in 1 file changed: 2 ins; 17 del; 3 mod Patch: https://git.openjdk.org/jdk/pull/21489.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21489/head:pull/21489 PR: https://git.openjdk.org/jdk/pull/21489
