Native POSIX Thread Library: Difference between revisions

Revision as of 23:27, 8 February 2016

Revision as of 11:53, 9 May 2016

Line 4:

Before the 2.6 version of the [[Linux kernel]], processes were the schedulable entities, and there were no special facilities for [[Thread (computer science)|threads]]. However, it did have a [[system call]] — <tt>[[clone (Linux system call)#Clone|clone]]</tt> — which creates a copy of the calling process where the copy shares the address space of the caller. The [[LinuxThreads]] project used this system call to provide kernel-level threads (most of the previous thread implementations in Linux worked entirely in [[Userland (computing)|userland]]). Unfortunately, it only partially complied with POSIX, particularly in the areas of signal handling, scheduling, and inter-process synchronization primitives.

To improve upon LinuxThreads, it was clear that some kernel support and a new threading library would be required. Two competing projects were started to address the requirement: [[NGPT]] (Next Generation POSIX Threads) worked on by a team which included developers from [[IBM]], and NPTL by developers at [[Red Hat]]. The NGPT team collaborated closely with the NPTL team and combined the best features of both implementations into NPTL. The NGPT project was subsequently abandoned in mid-2003 after merging it'sits best features into NPTL.

NPTL was first released in Red Hat Linux 9. Old-style Linux 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 preempt them when it arises, something that Windows was known to do better 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 Linux 9.<ref>[http://java.sun.com/developer/technicalArticles/JavaTechandLinux/RedHat/ Red Hat Linux 9 and Java 2 Platform, Standard Edition 1.4.2: A Winning Combination]</ref>