You will be hard-pressed to find any significant number of professional software engineers working on enterprise-grade software willing to deny that multithreaded software development is painful. However, why is it so hard to do well?
It is not that multithreaded programming is difficult per se—the difficultly lies in the complexity of thread synchronization. It is very difficult to build high concurrency using the thread model, especially models in which the state is shared. Anticipating every way that an action taken in one thread might affect all the others is nearly impossible once an application grows beyond the most basic of shapes. Entanglements and collisions multiply rapidly, sometimes ...
