[jdk17u-dev] RFR: 8310031: Parallel: Implement better work distribution for large object arrays in old gen [v2]
Richard Reingruber
rrich at openjdk.org
Thu Mar 7 09:13:01 UTC 2024
> I would like to backport this as a performance bug fix.
>
> We received bug reports from users which have some young pauses of 30s, and even up to 50s (normally <1s) running large Gerrit instances (200GB heap, 100 gc threads).
> We have tried to tune ParallelGC. Reducing the number of gc threads helps to make the pause time spikes smaller but this makes average pause times longer.
>
> This pr depends on
> https://github.com/openjdk/jdk17u-dev/pull/2226
> https://github.com/openjdk/jdk17u-dev/pull/2227
> https://github.com/openjdk/jdk17u-dev/pull/2228
>
> All hunks except the following 2 applied after a trivial preparation change.
> The 1st hunk of psCardTable.hpp did not apply because of different context. Resolved by inserting the new lines.
> The 2nd hunk of psScavenge.cpp did not apply because of different context. Resolved by inserting the new lines.
> Finally a few trivial changes are required (renaming and the like).
>
> Risk is medium. We've done the downstream backport already many weeks ago.
>
> I've tested on x86_64:
> jdk:tier1 TEST_VM_OPTS="-XX:+UseParallelGC"
> langtools:tier1 TEST_VM_OPTS="-XX:+UseParallelGC"
>
> Local CI Testing:
> The fix passed our CI testing (e.g. 2024-02-25): JTReg tests: tier1-4 of hotspot and jdk. All of Langtools and jaxp. JCK, SPECjvm2008, SPECjbb2015, Renaissance Suite, and SAP specific tests (also with ParallelGC).
> Testing was done with fastdebug builds on the main platforms and also on Linux/PPC64le.
Richard Reingruber 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.
-------------
Changes:
- all: https://git.openjdk.org/jdk17u-dev/pull/2230/files
- new: https://git.openjdk.org/jdk17u-dev/pull/2230/files/cf3280e7..cf3280e7
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=2230&range=01
- incr: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=2230&range=00-01
Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
Patch: https://git.openjdk.org/jdk17u-dev/pull/2230.diff
Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/2230/head:pull/2230
PR: https://git.openjdk.org/jdk17u-dev/pull/2230
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