RFR: 7902982: jcstress: Add samples for some mutex algorithms [v3]

[Michael Mirwaldt]

On Tue, 29 Jun 2021 13:11:53 GMT, Vladimir Sitnikov <vsitnikov at openjdk.org> wrote:

>> mmirwaldt for openjdk has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   removed ids for forbidden outcomes
>
> jcstress-samples/src/main/java/org/openjdk/jcstress/samples/concurreny/mutex/Mutex_01_NoAlgorithm.java line 50:
> 
>> 48: @Outcome(expect = ACCEPTABLE, desc = "Both actors have entered the critical section whenever they wanted")
>> 49: @State
>> 50: public class Mutex_01_NoAlgorithm {
> 
> I think it would be great to add `SynchronizedAlgorithm` as well.
> It would be the relevant middle-ground between `NoAltorithm` and `highly-sophisticated` Dekker/Peterson :)

Yes, that's a good idea. I will do it.

> jcstress-samples/src/main/java/org/openjdk/jcstress/samples/concurreny/mutex/Mutex_02_PetersonAlgorithm.java line 49:
> 
>> 47:  */
>> 48: @JCStressTest
>> 49: @Outcome(id = {"false, false"}, expect = ACCEPTABLE, desc = "Both actors have entered the critical section one after another")
> 
> What do you think of `Each actor observes another one as 'outside of the critical section'`?
> 
> It would help if you could add a comment describing what the outcome really means.
> It looks like every actor records if it observes another actor in the same critical section, however, that is not really clear from the code ��

Yes, you are right. I must confess that I had to think about 30min why Aleksey's solution work. His solution is clever.
Then I tried to explain it in comments but I failed. I will try it again.

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

PR: https://git.openjdk.java.net/jcstress/pull/85