The benefits of multithreaded programming can be broken down into four major categories:
- Responsiveness. Multithreading an interactive application may allow a program to continue running even if part of it is blocked or is performing a lengthy operation, thereby increasing responsiveness to the user. For instance, a multithreaded web browser could still allow user interaction in one thread while an image was being loaded in another thread.
- Resource sharing. By default, threads share the memory and the resources of the process to which they belong. The benefit of sharing code and data is that it allows an application to have several different threads of activity within the same address space.
- Economy of Overheads. Allocating memory and resources for process creation is costly. Because threads share resources of the process to which they belong, it is more economical to create and context-switch threads. In Solaris, for example, creating a process is about thirty times slower than is creating a thread, and context switching is about five times slower.
- Utilization of multiprocessor architectures. The benefits of multithreading can be greatly increased in a multiprocessor architecture, where threads may be running in parallel on different processors (real parallelism).