RFR: 8353496: SuspendResume1.java and SuspendResume2.java timeout after JDK-8319447

[Fei Yang]

On Mon, 12 May 2025 23:19:58 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

> The tests `SuspendResume1`, `SuspendResume2` and `SuspendResumeAll` are intermittently failed with a timeout (deadlock). The tests run with `-Djdk.virtualThreadScheduler.maxPoolSize=1` so there is only one carrier. The short sleep in `TestedThread.run` isn't sufficient to make progress. This will happen if tasks pushed by the delayed scheduler are executing before the tasks for the newly started virtual thread. FJP won't search other submission queues until the queue it keeps going back to is empty or there is contention. These deadlocks can be made better reproducible if the sleep in `TestedThread.run` is made minimal (1 millisecond).
> The fix is to increase the sleep to 50 milliseconds and also to decrease the busy part of the busy loop.
> 
> Testing:
> - Mach5 test runs of the fixed tests

FYI: The same tests are passing after this change on both my linux-aarch64 and linux-riscv64 platforms. Thanks.

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PR Comment: https://git.openjdk.org/jdk/pull/25194#issuecomment-2878399012