This is still on my list to review will get to it in the next day or so On Feb 7, 2023, at 8:23 AM, Eirik Bjorsnos <d...@openjdk.org<mailto:d...@openjdk.org>> wrote:
After finding a hash match, getEntryPos needs to compare the lookup name up to the encoded entry name in the CEN. This comparison is done by decoding the entry name into a String. The names can then be compared using the String API. This decoding step adds a significat cost to this method. This PR suggest to update the string comparison such that in the common case where both the lookup name and the entry name are encoded in ASCII-compatible UTF-8, decoding can be avoided and the byte arrays can instead be compared direcly. ZipCoder is updated with a new method to compare a string with an encoded byte array range. The default implementation decodes to string (like the current code), while the UTF-8 implementation uses JavaLangAccess.getBytesNoRepl to get the bytes. Both methods thes uses Arrays.mismatch for comparison with or without matching trailing slashes. Additionally, this PR suggest to make the following updates to getEntryPos: - The try/catch for IAE is redundant and can be safely removed. (initCEN already checks this and will throws IAE for invalid UTF-8). This seems to give a 3-4% speedup on micros) - A new test InvalidBytesInEntryNameOrComment is a added to verify that initCEN does in fact reject invalid UTF-8 in CEN file names and comments. (I found no existing test coverage for this) - The recursion when looking for "name/" matches is replaced with iteration. We keep track of any "name/" match and return it at the end of the search. (I feel this is easier to follow and it also gives a ~30% speedup for addSlash lookups with no regression on regular lookups) (My though is that including these additional updates in this PR might reduce reviewer overhead given that it touches the exact same code. I might be wrong on this, please advise :) I'm seeing a ~17% saving on the micro ZipFileGetEntry.getEntryHit (modified to use xalan.jar): Baseline: Benchmark (size) Mode Cnt Score Error Units ZipFileGetEntry.getEntryHit 512 avgt 15 74.941 ± 1.004 ns/op ZipFileGetEntry.getEntryHit 1024 avgt 15 84.943 ± 1.320 ns/op ZipFileGetEntry.getEntryHitUncached 512 avgt 15 120.371 ± 2.386 ns/op ZipFileGetEntry.getEntryHitUncached 1024 avgt 15 126.128 ± 1.075 ns/op ZipFileGetEntry.getEntryMiss 512 avgt 15 23.818 ± 0.838 ns/op ZipFileGetEntry.getEntryMiss 1024 avgt 15 29.762 ± 5.998 ns/op ZipFileGetEntry.getEntryMissUncached 512 avgt 15 59.405 ± 0.545 ns/op ZipFileGetEntry.getEntryMissUncached 1024 avgt 15 71.840 ± 2.455 ns/op ZipFileGetEntry.getEntrySlash 512 avgt 15 135.621 ± 4.341 ns/op ZipFileGetEntry.getEntrySlash 1024 avgt 15 134.190 ± 2.141 ns/op PR: Benchmark (size) Mode Cnt Score Error Units ZipFileGetEntry.getEntryHit 512 avgt 15 62.267 ± 1.329 ns/op ZipFileGetEntry.getEntryHit 1024 avgt 15 72.916 ± 2.428 ns/op ZipFileGetEntry.getEntryHitUncached 512 avgt 15 101.630 ± 1.154 ns/op ZipFileGetEntry.getEntryHitUncached 1024 avgt 15 113.161 ± 0.502 ns/op ZipFileGetEntry.getEntryMiss 512 avgt 15 23.003 ± 1.191 ns/op ZipFileGetEntry.getEntryMiss 1024 avgt 15 23.236 ± 1.114 ns/op ZipFileGetEntry.getEntryMissUncached 512 avgt 15 56.781 ± 1.505 ns/op ZipFileGetEntry.getEntryMissUncached 1024 avgt 15 67.767 ± 1.963 ns/op ZipFileGetEntry.getEntrySlash 512 avgt 15 73.745 ± 2.717 ns/op ZipFileGetEntry.getEntrySlash 1024 avgt 15 75.784 ± 1.051 ns/op To assess the impact on startup/warmup, I made a main method class which measures the total time of calling ZipFile.getEntry for all entries in the 109 JAR file dependenies of spring-petclinic. The shows a nice improvement (time in micros): Percentile Baseline Patch 50 % 23155 21149 75 % 23598 21454 90 % 23989 21691 95 % 24238 21973 99 % 25270 22446 STDEV 792 549 Count 500 500 Eirik Bjorsnos has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 20 additional commits since the last revision: - Merge branch 'master' into getentrypos-prefixmatch - Fix incorrect offset for the CEN "length of extra field". Fixed spelling of "invalid". - Spelling fix in test data for non-ascii latin1 string - Replace new shared secret with using getBytesNoRepl in UTF8ZipCoder.compare. Add a test case for UTF-8 encoded entry name which is latin1, but not ASCII - Rename test to InvalidBytesInEntryNameOrComment - Adjust whitespace - Some minor improvements to code comments - Micros seem to indicate that the range checks in Arrays.mismatch might have as much as 5% regression - Move String/byte[] comparison into ZipCoder. Change the default implementation to decode to string for comparison instead of encoding to bytes, this seems safer. Revert some changes from previous commits to parameters in the hasTrailingSlash method. - ByteBuffers for reading ZIP files must be little-endian - ... and 10 more: https://git.openjdk.org/jdk/compare/23f44474...06047377 ------------- Changes: - all: https://git.openjdk.org/jdk/pull/12290/files - new: https://git.openjdk.org/jdk/pull/12290/files/2c5e7c2c..06047377 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=12290&range=03 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12290&range=02-03 Stats: 22651 lines in 906 files changed: 9116 ins; 4377 del; 9158 mod Patch: https://git.openjdk.org/jdk/pull/12290.diff Fetch: git fetch https://git.openjdk.org/jdk pull/12290/head:pull/12290 PR: https://git.openjdk.org/jdk/pull/12290 [cid:E1C4E2F0-ECD0-4C9D-ADB4-B16CA7BCB7FC@home] Lance Andersen | Principal Member of Technical Staff | +1.781.442.2037 Oracle Java Engineering 1 Network Drive Burlington, MA 01803 lance.ander...@oracle.com<mailto:lance.ander...@oracle.com>
