SoftwareTransactionalMemory

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1 개요

static void Main()
{
    double myAccount;
    double yourAccount;

    myAccount = 1000;
    yourAccount = 500;

    double amountToTransfer = 150;
    myAccount -= amountToTransfer;
    yourAccount += amountToTransfer;
}

스레드 세이프하지 않은 코드. +- 하는 부분에서 다른 스레드가 끼어들면 콩가루 된다.


static void Main(string[] args)
{
    INstmObject<double> myAccount;
    INstmObject<double> yourAccount;

    myAccount = NstmMemory.CreateObject<double>(1000);
    yourAccount = NstmMemory.CreateObject<double>(500);

    using (INstmTransaction tx = NstmMemory.BeginTransaction())
    {
        double amountToTransfer = 150;

        myAccount.Write(myAccount.Read() - amountToTransfer);
        yourAccount.Write(yourAccount.Read() + amountToTransfer);

        tx.Commit();
    }

    Console.WriteLine("My account balance: {0}", myAccount.Read());
    Console.WriteLine("Your account balance: {0}", yourAccount.Read());
}

STM을 통해 스레드 세이프해진 코드. 즉 로직 자체는 건드리지 않으면서 스레드 세이프한 코드를 만드는 데 도움을 주는 장치...라는 느낌. 위키피디어의 설명을 옮겨 보자면...

In computer science, software transactional memory (STM) is a concurrency control mechanism analogous to database transactions for controlling access to shared memory in concurrent computing. It functions as an alternative to lock-based synchronization, and is typically implemented in a lock-free way.

즉 ThreadsProgramming이 보편화됨에 따라, 기존의 락을 이용하는 동기화 방식이 너무 복잡하다고 여겨져 나온 대안 정도라는 말이 되겠다. 일반적으로 LockFreeAlgorithm을 이용하여 구현되는 모양이다.

2 목록

3 링크

• Software Transactional Memory - Making multithreading easier
  
• Software Transactional Memory II - Isolation of Changes to Transactional Objects
  
• Software Transactional Memory III - Making Transactions Atomic
  
• Software Transactional Memory IV - Thread-Bound Transactions
  
• Software Transactional Memory V - Integration with System.Transactions
  
• Software Transactional Memory VI - Becoming Aspect Oriented with PostSharp
  
• Software Transactional Memory VII - Automatic retry of failed transactions
  
  
• http://www.calumgrant.net/atomic/
  
• Transactional Programming
  

• see also ThreadsProgramming, ThreadSynchronization
  

• CategorySystemProgramming