In the [[Linux]] operating system, the '''Native POSIX Thread Library''', also known as ('''NPTL, in the world of the [[Linux kernel]]''') is a software feature that enables the [[Linux kernel]] to run programs written to use [[POSIX]]-style [[Thread (computer science)|threads]] very fastefficiently.
In tests, it succeeded in running 100,000 threads simultaneously on a [[IA-32]] which were started in two [[second]]s. In comparison, this test under a kernel without NPTL would have taken around 15 minutes.
== History ==
NPTL first came out in [[Red Hat]] 9.0. Old-style POSIX threading is known for having trouble with threads that refuse to yield to the system occasionally because it does not take the opportunity to preemptively yield them when it arises, something that Windows iswas known forto doingdo superiorlybetter at the time. Red Hat claimed that NPTL fixed this problem in an article on the [[Java programming language|Java]] website about Java on Red Hat 9.
== NPTL vs. Windows Threading Experiments ==
In [[research]] done by Edward Rice in [[February]] of [[2004]], NPTL was compared to the [[Microsoft_WindowsMicrosoft Windows|Windows]] Threading Library. A program written in Java created multiple threads that ran at the same time. This program was run on both Windows and Linux on a dual boot system [[Intel]] non-[[hyper-threading]] chipset. It was discovered that Windows handled threads that yielded often better than Red Hat Linux 9, but Red Hat Linux 9 handled threads that yielded less frequently better than Windows. It was concluded that this was the result of the [[time]] it takes for a thread to yield and the [[virtual machine]] to pick a new one.
