RFR: Cleanup NumberSeq additions [v4]
Aleksey Shipilev
shade at openjdk.org
Fri Apr 28 19:40:24 UTC 2023
> I have been looking into how to decrease our upstream exposure for `NumberSeq` changes, and it seems to be not solvable in an easy way. Normally, I would add `AbsSeq::add(AbsSeq& other)` methods and get to that from `HdrSeq::add(HdrSeq& other)`, and that almost works. The remaining bit is figuring out the decaying average/variance thingie.
>
> I spent an hour trying to come up with easily provable equations for _combining_ the decaying average/variance. The decaying average is somewhat easy, although there are boundary problems (decaying average treats 0-th element without adjustments, which requires remembering the `_last` element to compensate). Decaying variance looks remarkably scary in the few of my approaches.
>
> If we enter with current code upstream, it would be the uphill battle to implemented decays and prove they work. So instead, I took the alternative approach of doing everything inside Shenandoah code, except the decays. This reverts `numberSeq.*` to upstream state.
>
> Additional testing:
> - [x] Linux x86_64 fastdebug `hotspot_gc_shenandoah`
> - [x] Linux AArch64 fastdebug `hotspot_gc_shenandoah`
> - [x] GitFarm
Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
Touchup
-------------
Changes:
- all: https://git.openjdk.org/shenandoah/pull/268/files
- new: https://git.openjdk.org/shenandoah/pull/268/files/e6887c3e..ad5492ef
Webrevs:
- full: https://webrevs.openjdk.org/?repo=shenandoah&pr=268&range=03
- incr: https://webrevs.openjdk.org/?repo=shenandoah&pr=268&range=02-03
Stats: 10 lines in 2 files changed: 0 ins; 0 del; 10 mod
Patch: https://git.openjdk.org/shenandoah/pull/268.diff
Fetch: git fetch https://git.openjdk.org/shenandoah.git pull/268/head:pull/268
PR: https://git.openjdk.org/shenandoah/pull/268
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