[fpc-devel] LockFree Queue algorithm

DarekM darekm at emadar.com
Sun Jan 27 14:51:35 CET 2008

Micha Nelissen pisze:
> DarekM wrote:
>> Hi
>> This is my proposition of algorithm and its implementing multithreaded
>> FIFO queue without lock.
> Hmm 'Push' and 'Pop' sound like a stack, but the implementation seems to
> implement a FIFO indeed, with a head and tail.
It should be enqueue and dequeue. I was left  because first I try 
implement stack.

> You're sure about the situation where two threads are accessing head and
> tail at the same time, and there is only one item in your FIFO ?
Of course (if  CAS (interlockedCompareExchange)  has proper 
implementation , that, I think, should be avoided
Queue is empty when tail=head,
when is not equal only one thread can receive object form queue,  second 
make again iteration

The same with ABA problem.


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