Menu
I am picking up C# 4.0 and one of the things which is confusing me, is the barrier concept.
Is this not just like using the WaitAll method of WaitHandle? Doesn't that wait for all threads to finish?
I learnt the barrier construct from this page: http://www.managed-world.com/archive/2009/02/09/an-intro-to-barrier.aspx
However, it seems just like the WaitAll method. What am I missing? What's the difference here?
Thanks.
686
In parallel computing, a barrier is a type of synchronization method. A barrier for a group of threads or processes in the source code means any thread/process must stop at this point and cannot proceed until all other threads/processes reach this barrier.
A barrier or barricade is a physical structure which blocks or impedes something.
In computing, a memory barrier, also known as a membar, memory fence or fence instruction, is a type of barrier instruction that causes a central processing unit (CPU) or compiler to enforce an ordering constraint on memory operations issued before and after the barrier instruction.
The pthread_barrier_wait() function shall synchronize participating threads at the barrier referenced by barrier. The calling thread shall block until the required number of threads have called pthread_barrier_wait() specifying the barrier.
It sounds like you are curious as to why a Barrier would be preferred over a WaitHandle + WaitForAll derivative? Both can achieve a similar goal if structured properly.
I'm not extremely familiar with Barrier but one advantage that jumps out at me is a resource issue. To synchronize N threads with a Barrier requires only a single Barrier instance. To synchronize N threads via a WaitHandle and WaitAll requires N handles. These resources are cheap but not free. Reducing the number of resources to synchronize a group of threads has it's advantages.
127
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
