On Sun, 6 Oct 2024 21:45:08 GMT, Claes Redestad <redes...@openjdk.org> wrote:
>> #14632 showed that coalescing loads in the `ZipUtils` utility methods could >> improve performance in zip-related microbenchmarks, but doing so would >> increase startup overheads. Progress was stalled as we backed out some >> related early use of `ByteArray(LittleEndian)` and started exploring merge >> store optimizations in C2. >> >> In this PR I instead suggest using `Unsafe` directly to coalesce `short`, >> `int`, and `long` reads from zip data. Even with explicit bounds checking to >> ensure these utilities are _always_ safe there are significant improvements >> both to lookup speed and speed of opening zip files (most if not all bounds >> checks are optimized away): >> >> >> make test TEST=micro:java.util.zip.ZipFile >> >> Name (size) Cnt Base Error Test >> Error Unit Change >> GetEntry.getEntryHit 512 15 37.999 ± 0.841 34.641 ± >> 0.389 ns/op 1.10x (p = 0.000*) >> GetEntry.getEntryHit 1024 15 39.557 ± 0.523 36.959 ± >> 1.488 ns/op 1.07x (p = 0.000*) >> GetEntry.getEntryHitUncached 512 15 69.250 ± 0.931 64.851 ± >> 0.987 ns/op 1.07x (p = 0.000*) >> GetEntry.getEntryHitUncached 1024 15 71.628 ± 0.307 67.927 ± >> 0.714 ns/op 1.05x (p = 0.000*) >> GetEntry.getEntryMiss 512 15 22.961 ± 0.336 22.825 ± >> 0.188 ns/op 1.01x (p = 0.158 ) >> GetEntry.getEntryMiss 1024 15 22.940 ± 0.115 23.502 ± >> 0.273 ns/op 0.98x (p = 0.000*) >> GetEntry.getEntryMissUncached 512 15 35.886 ± 0.429 35.598 ± >> 1.296 ns/op 1.01x (p = 0.395 ) >> GetEntry.getEntryMissUncached 1024 15 38.168 ± 0.911 36.141 ± >> 0.356 ns/op 1.06x (p = 0.000*) >> Open.openCloseZipFile 512 15 62425.563 ± 997.455 56263.401 ± >> 896.892 ns/op 1.11x (p = 0.000*) >> Open.openCloseZipFile 1024 15 117491.250 ± 962.928 108055.491 ± >> 1595.577 ns/op 1.09x (p = 0.000*) >> Open.openCloseZipFilex2 512 15 62974.575 ± 911.095 57996.388 ± >> 910.929 ns/op 1.09x (p = 0.000*) >> Open.openCloseZipFilex2 1024 15 119164.769 ± 1756.065 108803.468 ± >> 929.483 ns/op 1.10x (p = 0.000*) >> * = significant >> >> >> This PR also address some code duplication in `ZipUtils`. >> >> An appealing alternative would be to implement a merge load analogue to the >> merge store optimizations in C2. Such optimizations would be very welcome >> since it would improve similar code outside of java.base (jdk.zi... > > Claes Redestad has updated the pull request incrementally with one additional > commit since the last revision: > > Rename get64 -> get64S Hi Claes, Looks reasonable to me. thank you for your efforts here ------------- Marked as reviewed by lancea (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/21377#pullrequestreview-2352737725
