1. Reduce cost and improve efficiency

Reduce the time of thread creation and destruction and the overhead of system resources;

At the same time, it improves the response speed of the system. When a new task arrives, it can be executed immediately by reusing the existing thread without waiting for the creation of a new thread.

2. Improve the manageability of threads

It is convenient to control the number of concurrent threads. Unlimited thread creation may lead to excessive memory consumption, resulting in oom, and will cause excessive CPU switching. There is a time cost for CPU switching threads: it is necessary to keep the scene of the current thread and restore the scene of the thread to be executed.

It can allocate, tune and monitor threads in a unified way, so as to improve the response speed, and provide more powerful functions, such as delaying and timing thread pool.