JDK-8246677 caused 16x performance regression in OpenJDK Tip SynchronousQueue

[Astigeevich, Evgeny]

Hi Alan,

I was benchmarking SynchronousQueue from the OpenJDK Tip on Linux. I found its performance is 16 times lower than the performance of SynchronousQueue from OpenJDK 11. The regression exists on Linux x86_64 and Linux aarch64. Comparing SynchronousQueue implementations I found the OpenJDK Tip SynchronousQueue is changed by PR https://github.com/openjdk/jdk/pull/1645 (JDK-8246677<https://bugs.openjdk.java.net/browse/JDK-8246677>). Reverting SynchronousQueue to the version before the PR fixes the regression. I cannot find any performance data backing the PR.

I raised a JBS issue: https://bugs.openjdk.java.net/browse/JDK-8267502
It has details how to reproduce the issue.

As we are approaching JDK 17 Rampdown Phase One (2021/06/10), could the issue be triaged?

Thanks,
Evgeny Astigeevich



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