On Mon, 7 Sep 2026 12:34:06 GMT, Jorn Vernee <[email protected]> wrote:

>> See the JBS issue for the full explanation of the issue.
>> 
>> Now that https://github.com/openjdk/jdk/pull/25315 was integrated, we are 
>> able to reliably scan for session oops in a frame, and only deoptimize those 
>> frames where the oop is live.
>> 
>> I ran the `ConcurrentClose` benchmark before and after this patch, and these 
>> were the results:
>> 
>> 
>> Before:
>> 
>> Benchmark                                        Mode  Cnt   Score   Error  
>> Units
>> ConcurrentClose.sharedClose                      avgt   10  10.139 ± 0.416  
>> us/op
>> ConcurrentClose.sharedClose:closing              avgt   10  29.288 ± 1.257  
>> us/op
>> ConcurrentClose.sharedClose:memorySegmentAccess  avgt   10   0.651 ± 0.030  
>> us/op
>> ConcurrentClose.sharedClose:otherAccess          avgt   10   0.478 ± 0.026  
>> us/op
>> 
>> After:
>> 
>> Benchmark                                        Mode  Cnt   Score   Error  
>> Units
>> ConcurrentClose.sharedClose                      avgt   10   9.860 ± 0.387  
>> us/op
>> ConcurrentClose.sharedClose:closing              avgt   10  28.641 ± 1.175  
>> us/op
>> ConcurrentClose.sharedClose:memorySegmentAccess  avgt   10   0.470 ± 0.013  
>> us/op
>> ConcurrentClose.sharedClose:otherAccess          avgt   10   0.468 ± 0.015  
>> us/op
>> 
>> 
>> We can see that now the unrelated memory access in `memorySegmentAccess` is 
>> no longer being affected by a scope being closed in another thread.
>> 
>> Testing: `jdk_foreign` suite, and I repeat ran 
>> `java/foreign/TestHandshake.java` 50 times as well, which is our stress test 
>> for shared scopes.
>> 
>> ---------
>> - [x] I confirm that I make this contribution in accordance with the 
>> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai).
>
> Jorn Vernee has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   update copyright year

I think this is ready to be merged now. Please have another look

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

PR Comment: https://git.openjdk.org/jdk/pull/30926#issuecomment-5604147093

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