https://github.com/ebyrds/szymanskis_mutex

Algorithm devised by Boleslaw Szymanski. This MutEx has linear wait and only 5 communication variables
https://github.com/ebyrds/szymanskis_mutex

mutex mutex-lock mutex-synchronisation mutexes race-conditions ruby rubygem szymanski

Last synced: 2 months ago
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Algorithm devised by Boleslaw Szymanski. This MutEx has linear wait and only 5 communication variables

• Host: GitHub
• URL: https://github.com/ebyrds/szymanskis_mutex
• Owner: EByrdS
• License: mit
• Created: 2018-10-11T15:09:37.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2018-10-12T18:10:36.000Z (about 6 years ago)
• Last Synced: 2024-04-25T19:44:26.416Z (8 months ago)
• Topics: mutex, mutex-lock, mutex-synchronisation, mutexes, race-conditions, ruby, rubygem, szymanski
• Language: Ruby
• Size: 32.2 KB
• Stars: 3
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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# Szymański's Mutual Exclusion Algorithm

This algorithm is modeled on a waiting room with an entry and exit doorway.

Initially the entry door is open and the exit door is closed.

All processes which request entry into the critical section at the same time

enter the waiting room; the last of them closes the entry door and opens

the exit door. The processes then enter the critical section one by one.

The last process to leave the critical section closes the exit door and

reopens the entry door so he next batch of processes may enter.

## Getting Started

Install the gem or add it to the Gemfile.

```

$ gem install szymanskis_mutex

```

Provide a block containing the critical section to the class method

`mutual_exclusion(concern)`. The parameter `concern` is used so that

you can have different use cases without them accessing the same variables.

(You can have as many separate MutEx as you want.)

```ruby

class RaceConditionReproducer

 @@value = 0

 def mutex_increment

   SzymanskisMutex.mutual_exclusion(:add) { unsafe_increment }

 end

 def unsafe_increment

   sleep 2

   temp = @@value

   sleep 2

   temp += 1

   sleep 2

   @@value = temp

 end

end

```

The MutEx will work across different instances of the same class as

it works with class variables.

## Contribution

Pull Requests will be reviewed before merging. Issues are being addressed.

All Pull Requests must contain specs for the changes.