RFR: 8344009: Improve compiler memory statistics

[Ashutosh Mehra]

On Tue, 25 Feb 2025 16:39:14 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>>> > @robcasloz I identified and hopefully fixed a small issue that hit the "disabled" path. Turns out we allocate arena chunks a lot more frequently than I thought, and the new unconditional call to Thread::current() in there was hurting a bit. I now avoid this unless I know the statistic is enabled.
>>> > With this patch, on my machine the difference between unpatched and patched JVM with stats disabled is below one standard deviation for the benchmark in question.
>>> 
>>> Great, thanks! Will re-run benchmarking and report results early next week.
>> 
>> Functional test results (Oracle tier1-5) still look good for the latest commit (dd7a06ad). I can confirm that the C2 speed regression on our linux-x64 machines is almost fully mitigated. The 2-3% regression on our macosx-aarch64 machines does not seem to be addressed by the latest changes though, but as I mentioned before I think it is in the acceptable range (and only affects one benchmark).
>
> @robcasloz, @ashu-mehra thanks a lot for your reviews. I incorporated most of them into the PR.

Changes look good to me. Thanks @tstuefe  for addressing the comments.

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PR Comment: https://git.openjdk.org/jdk/pull/23530#issuecomment-2683863222