On Fri, 15 Nov 2024 10:19:46 GMT, Aleksey Shipilev <sh...@openjdk.org> wrote:
>> See the bug for more discussion and reproducer. This PR replaces the ad-hoc >> linked list with segmented list of arrays. Arrays are easy targets for GC. >> There are possible improvements here, most glaring is parallelism that is >> currently knee-capped by global synchronization. The synchronization scheme >> follows what we have in original code, and I think it is safer to continue >> with it right now. >> >> I'll put performance data in a separate comment. >> >> Additional testing: >> - [x] Original reproducer improves drastically >> - [x] New microbenchmark shows no regression on "churning" tests, which >> covers insertion/removal perf >> - [x] New microbenchmark shows improvement on Full GC times (crude, but >> repeatable), serves as a proxy for reproducer >> - [x] `java/lang/ref` tests in release >> - [x] `all` tests in fastdebug > > Aleksey Shipilev has updated the pull request incrementally with one > additional commit since the last revision: > > Do not need -ea -esa in tests, our testing infra adds them already src/java.base/share/classes/jdk/internal/ref/CleanerImpl.java line 249: > 247: * the time. > 248: */ > 249: private Node cache; Should the cache be soft, as it keeps the 4096-long array reachable? Not familiar with this matter, please enlighten me. src/java.base/share/classes/jdk/internal/ref/CleanerImpl.java line 356: > 354: > 355: // Linked list structure. > 356: Node prev; The prev link seems only ever written but never read. This can be a singly-linked list, I believe. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/22043#discussion_r1844252581 PR Review Comment: https://git.openjdk.org/jdk/pull/22043#discussion_r1844256631
