RFR: 8349539: [leyden] Allow dumping nmethods that reference archived hidden klasses

[Aleksey Shipilev]

On Thu, 6 Feb 2025 11:52:25 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> WIP. I have yet to see if this has a good performance impact.
> 
> Studying the bailout reasons for JavacBenchApp, I notices the majority of nmethod store bailouts are due to referencing the hidden klasses. Those checks seem to be from the initial commit. I wonder if we can actually skip hidden klass checks, now that we archive lots of those since invokedynamic AOT was implemented.

Look at "user" time, this is what we save without recompiling the methods that get bailed from the archive.


$ rm -f *.cds*; hyperfine -w 3 -r 10 "build/linux-x86_64-server-release/images/jdk/bin/java -XX:CacheDataStore=JavacBenchApp.cds -cp JavacBenchApp.jar JavacBenchApp 500";

# Before
  Time (mean ± σ):      1.556 s ±  0.013 s    [User: 4.575 s, System: 0.501 s]
  Range (min … max):    1.538 s …  1.580 s    10 runs

# After
  Time (mean ± σ):      1.551 s ±  0.016 s    [User: 3.646 s, System: 0.458 s]
  Range (min … max):    1.536 s …  1.586 s    10 runs

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PR Comment: https://git.openjdk.org/leyden/pull/33#issuecomment-2640329448