RFR: CODETOOLS-7903021: jcstress: Dining Philosophers problem sample

[Michael Mirwaldt]

On Thu, 26 Aug 2021 17:28:34 GMT, Michael Mirwaldt <github.com+6693355+mmirwaldt at openjdk.org> wrote:

> This s my initial draft fo a sample testing solutions for the dining philosophers problem:
> - Wikipedia explains it on https://en.wikipedia.org/wiki/Dining_philosophers_problem
> - It runs within 13min on my machine.
> - It includes a short comment about the motivation for that sample and
> a reference link to the wikipedia article about the dining philosophers problem. 
> - It offers 3 different solutions: with monitors, with reentrant locks and with semaphores

I get more and more the feeling this sample and the next samples following are too sophisticated for JCStress because they just need too many actors. 
You wrote in one of your emails JCStress only supports at most 4 actors, better only 3 actors at most. 
While the Dining Philosophers sample would run with 3 actors, I don't think this will work for the next samples following. I am afraid the reader-writer problem will never run with only 4 actors because overhead of the locking protocol destroys all results.

Do you want to focus on the JMM samples, the CAS samples and the Mutex samples which don't need many actors in JCStress  or do you also want to support sophisticated lock protocols which will need more than 4 actors in future?
If the answer is "No, JCStress will never support more than 4 actors because ...", then I would not add this sample and the others because they don't make much sense. It would invite users to use JCStress for use cases it was not made.

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PR: https://git.openjdk.java.net/jcstress/pull/93