RFR: 8344009: Improve compiler memory statistics

[Roberto Castañeda Lozano]

On Thu, 20 Feb 2025 13:59:57 GMT, Roberto Castañeda Lozano <rcastanedalo 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).

-------------

PR Comment: https://git.openjdk.org/jdk/pull/23530#issuecomment-2677775924