Performance Regression Caused by [GR-36260] Use Reference.reachabilityFence

[smarr]

Yesterday, when updating Graal in TruffleSOM, I noticed a performance regression, which after bisecting through the history, seems to be attributable to 566d7bf

Comparing the performance of the merge before and this one, gives me the following results: https://rebench.stefan-marr.de/compare/TruffleSOM/25c58e39b076e4ca8edfd571aca0fdb855793403/b6f98b977f38193b3702dcfc3fd0fceca4bf4e79

For completeness, the results against the latest version: https://rebench.stefan-marr.de/compare/TruffleSOM/1b0b90a9a7feba9b8e584daff46b95bb87a91901/1836c350e56a613a7637ed3fcf719c43e364a05a

Recursive benchmarks seem to make worse inlining decisions, but other benchmarks, especially the bytecode interpreter ones are suffering, too.

To reproduce, the following instructions will checkout TruffleSOM with Graal of today in a submodule.

git clone -b truffle-update-june-30 --recursive https://github.com/smarr/TruffleSOM
cd TruffleSOM
ant compile
./som -i -cp Smalltalk:Examples/Benchmarks/LanguageFeatures:Examples/Benchmarks/TestSuite Examples/Benchmarks/BenchmarkHarness.som --gc Bounce 250 4000

The -i flag enables IGV graph dumping.
To debug with a Java debugger, use -d.
To see the plain command line, use -vv.
The -LG flag disables the use of libgraal, which one probably wants to debug Graal.

/cc @woess

[eregon]

Also noticed on Ruby PSD benchmarks (GR-39711)

[woess]

Thanks for the report. The regression should be fixed as of 9e628e5.

[smarr]

@woess @christianwimmer hm. This doesn't seem to solve the issue.
I'll investigate a bit further, I just updated to the latest version, but it does not seem to help revert the performance impact observed on Bounce or TreeSort.

[smarr]

Ok, I can confirm that there's indeed the expected performance improvement right on the merge commit https://rebench.stefan-marr.de/compare/TruffleSOM/c0ca77fed790812838ba35bf29eac9b2f2349a05/5f94c1ae1cec7573f872915048e785fc329102dc

Though, afterwards, it breaks again.

[smarr]

Never mind. I messed up the update, and I compare against a version that was before the merge was fixed. All good.