RFR: 8341485: GenShen: Make evac tracker a non-product feature and confine it to generational mode

[Y. Srinivas Ramakrishna]

On Thu, 3 Oct 2024 18:23:32 GMT, William Kemper <wkemper at openjdk.org> wrote:

> During the course of development of the generational mode, we added a feature to keep track of which threads were evacuating objects and how many evacuations lost the race. The instrumentation added unwarranted overhead. This change makes this instrumentation a non-product feature for the generational mode and removes it entirely from the non-generational modes.

Looks good to me.

(Left a comment/question about another change that kinda snuck in; but it's probably OK to sneak it in here rather than the extra overhead of a separate PR, if you intended it...)

src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp line 1258:

> 1256:       }
> 1257:     }
> 1258: 

This change in behavior is an intentional part of this change? It may be the right change to make, but seems unrelated to the bug summary and the main thrust of the changes. Should this be broken off into a separate ticket?

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Marked as reviewed by ysr (Committer).

PR Review: https://git.openjdk.org/shenandoah/pull/506#pullrequestreview-2346814180
PR Review Comment: https://git.openjdk.org/shenandoah/pull/506#discussion_r1786921819