RFR: 7902982: jcstress: Add samples for some mutex algorithms [v10]

[mmirwaldt for openjdk]

On Tue, 29 Jun 2021 15:44:45 GMT, mmirwaldt for openjdk <github.com+86246875+mmirwaldt-openjdk at openjdk.org> wrote:

>> I have implemented 3 more samples:
>> *) the NoAlgorithm sample should show users of JCStress how they can define a critical section in a simple way
>> *) one sample for the Peterson's algorithm 
>> *) one sample for the Dekker's algorithm 
>> I have translated the pseudo code implementations of the English wikipedia articles into Java.
>> I have also tried out those examples: they compile and they run without any problems.
>
> mmirwaldt for openjdk has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - gave state annotation its own line
>  - reorganized the imports
>  - changed the outcomes of the mutex samples

I have got one question which bothers me:
Wouldn't it make sense if the mutex algorithms call Thread.onSpinWait() instead of busy waiting?
I mean e.g. 
...
while (flagForActor2 && turn == 2) {
     Thread.onSpinWait();
}
...
instead of 
...
while (flagForActor2 && turn == 2); // wait
...
in the Peterson algorithm.
Wouldn't that be better?

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

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