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+# Maat concurrency
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+
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+## Safe Points
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+
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+* Creation of shared upvalues
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+* Marking a collectable object shared
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+*
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+
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+
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+## Synchronization Points
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+
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+(if more than one thread to execute Maat code)
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+
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+* Check environment type(single or multi-threaded?)
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+* Shared short strings
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+* Cached strings
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+* Int -> Str cache
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+* Propagating over shared collectable objects.
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+* Insertion of shared objects into LSOs
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+* Shared memory operations (READ, WRITE, READ-MODIFY-WRITE(RMW))
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+*
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+
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+Memory shared accross maatines are via global symbols and upvalues, Maat attemps
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+to automatically synchronize concurrent access to shared memory either through
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+mutexes or atomic operations.
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+
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+Suppose we are in a multi-threaded environment and that variable `x` is accessible
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+to all maatines, having more than one threads to execution maat code implies more
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+then one maatine, let us determine all the synchronization points in each of the
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+operations below.
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+
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+1. Write operation
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+
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+```
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+x = 20
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+```
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+
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+2. Read operation
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+
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+```
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+say x + 100
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+```
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+
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+3. RMW (Read-Modify-Write) operation
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+
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+```
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+x = x + 1
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+```
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+
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+```
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+x = [1, 2]
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+
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+x.push(3)
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+```
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+
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+
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+## Communicate By Sharing: Channels
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