Interlocked.MemoryBarrierProcessWide Method

Definition

Namespace:

System.Threading

Assembly:

System.Threading.dll

Source:

Interlocked.CoreCLR.cs

Provides a process-wide memory barrier that ensures that reads and writes from any CPU cannot move across the barrier.

public:
 static void MemoryBarrierProcessWide();

public static void MemoryBarrierProcessWide ();

static member MemoryBarrierProcessWide : unit -> unit

Public Shared Sub MemoryBarrierProcessWide ()

Remarks

The MemoryBarrierProcessWide method differs from the "normal" MemoryBarrier method as follows:

• The normal memory barrier ensures that the reads and writes from the current CPU can't move across the barrier. The process-wide memory barrier ensures that any read or write from any CPU being used in the process can't move across the barrier.

• The normal memory barrier allows reasonable shared access if every thread accessing the data uses barriers. The process-wide memory barrier forces other CPUs to synchronize with process memory (for example, to flush write buffers and synchronize read buffers). This allows for non-interlocked operations on some threads and still have reasonable shared access.

• The normal memory barrier imposes very little overhead; normal interlocked operations probably cost fewer than a hundred cycles. The process-wide memory barrier is very expensive. It has to force every CPU in the process do to something, at a probable cost of thousands of cycles.

The MemoryBarrierProcessWide method also suffers from all the subtleties of lock-free programming. Nevertheless, this method can be extremely useful when you actually need to call it, which should be rare.

This method wraps a call to FlushProcessWriteBuffers on Windows and sys_membarrier on Linux.