RFR: 8271579: G1: Move copy before CAS in do_copy_to_survivor_space [v3]

Fri Aug 13 06:45:26 UTC 2021

On Fri, 6 Aug 2021 02:15:55 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Propose to move copy before CAS in do_copy_to_survivor_space, as we found this will improve G1 performance. Specjbb shows 3.7% in critical on aarch64, no change in max.
>> 
>> After this change copy_to_survivor in G1 is also aligned with PS's copy_to_survivor.
>
> Hamlin Li has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR.

Lgtm; perf results with the mark word change (see earlier) look good, i.e. no particular perf changes. Please wait for a second review.

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Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4983