Mutex vs Monitor
Explore the differences between mutex and monitor in C# concurrency, focusing on how monitors combine mutual exclusion with condition variables. Understand how monitors solve spin waiting by enabling threads to wait and signal on predicates, and why using a while loop is essential for correct synchronization.
We'll cover the following...
Mutex vs Monitor
Continuing our discussion from the previous section on locking and signaling mechanisms, we'll now pore over an advanced concept, the monitor. Note that in the theory of operating systems a monitor is implemented using condition variables, however, C# (or Java) don't implement a type that corresponds to an equivalent of the theoretical condition variable. Instead every objectinherently implements one condition variable, and the Monitor class provides static Wait(), Pulse and PulseAll methods to manipulate an object’s condition variable. The discussion that follows isn't specific to C# but about the general concept of a monitor.
Concisely, a monitor is a mutex and then some. Monitors are generally language-level constructs whereas mutex and semaphore are lower-level or OS-provided constructs.
To understand monitors, let's first see the problem they solve. Usually, in multi-threaded applications, a thread needs to wait for some program predicate to be true before it can proceed forward. Think about a producer/consumer application. If the producer hasn't produced anything the consumer can't consume anything. So the consumer must wait on a predicate that lets the ...