RFR: 8310551: vmTestbase/nsk/jdb/interrupt/interrupt001/interrupt001.java timed out due to missing prompt [v3]

[Chris Plummer]

On Thu, 13 Jul 2023 02:13:54 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> After [JDK-8308232](https://bugs.openjdk.org/browse/JDK-8308232), both the test and the debuggee shared the same waittime of 5 minutes. The test would wait up to 5 minutes for the expected prompt, but the debuggee would also in some cases wait 5 minutes before generating the prompt, which sometimes was just a bit too late. Before [JDK-8308232](https://bugs.openjdk.org/browse/JDK-8308232), the debuggee would wait at most 2 minutes before generating the prompt, so it was always generated in time.
>> 
>> The main issue is that after the while loop checks that there are still uninterrupted threads remaining, the last of the threads is interrupted before the wait() call is made. This means wait() won't return until it times out, and by then it is too late, and the test side has already timed out waiting for the prompt.
>> 
>> The fix is to widen the synchronized block so the count of not interrupted threads remains correct until `wait()` is entered. The other choice was to refetch the count after entering the synchronized block, which is what I did for the initial fix, but widening seems a better choice so no refetch is needed.
>> 
>> For details see https://bugs.openjdk.org/browse/JDK-8310551?focusedCommentId=14594838&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14594838
>> 
>> Tested with 300 runs each on linux-x64 and linux-aarch64 with -Xcomp options that reproduced the issue, and then again with no options.
>
> Chris Plummer has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Suggestion from David. Widen synchronized block so it is not necessarry for notInterrupted to be atomic.

Thanks Serguei and Kevin!

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PR Comment: https://git.openjdk.org/jdk/pull/14817#issuecomment-1636247100