ULE is the default scheduler for the

FreeBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

(versions 7.1 and forward) for the i386 and AMD64 architectures. It was introduced in

version 5, but it was disabled by default for a time in favor of the traditional BSD scheduler until it reached maturity. The original BSD scheduler does not make full use of SMP or SMT, which is important in modern computing environments. The primary goal of the ULE project is to make better use of SMP and SMT environments. ULE should improve performance in both

uniprocessor A uniprocessor system is defined as a computer system that has a single central processing unit that is used to execute computer tasks. As more and more modern software is able to make use of multiprocessing architectures, such as SMP and MPP, t ...

and

multiprocessor Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There ar ...

environments, as well as interactive response under heavy load. The user may switch between the BSD scheduler and ULE using a kernel compile-time tunable.

References

Sources

* BSD software Processor scheduling algorithms {{operating-system-stub