RFR: 8329597: C2: Intrinsify Reference.clear [v6]
Aleksey Shipilev
shade at openjdk.org
Mon Sep 30 16:59:16 UTC 2024
> [JDK-8240696](https://bugs.openjdk.org/browse/JDK-8240696) added the native method for `Reference.clear`. The original patch skipped intrinsification of this method, because we thought `Reference.clear` is not on a performance sensitive path. However, it shows up prominently on simple benchmarks that touch e.g. `ThreadLocal` cleanups. See the bug for an example profile with `RRWL` benchmarks.
>
> We need to know the actual oop strongness/weakness before we call into C2 Access API, this work models this after existing code for `refersTo0` intrinsics. C2 Access also need a support for `AS_NO_KEEPALIVE` for stores.
>
> Additional testing:
> - [ ] Linux x86_64 server fastdebug, `all`
> - [ ] Linux AArch64 server fastdebug, `all`
Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
Also dispatch to slow-path on other arches
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/20139/files
- new: https://git.openjdk.org/jdk/pull/20139/files/8ba681a4..4fe4a911
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=20139&range=05
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=20139&range=04-05
Stats: 6 lines in 3 files changed: 6 ins; 0 del; 0 mod
Patch: https://git.openjdk.org/jdk/pull/20139.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/20139/head:pull/20139
PR: https://git.openjdk.org/jdk/pull/20139
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