multithreading

<parallel> Sharing a single CPU between multiple tasks (or "threads") in a way designed to minimise the time required to switch threads. This is accomplished by sharing as much as possible of the program execution environment between the different threads so that very little state needs to be saved and restored when changing thread. Multithreading differs from multitasking in that threads share more of their environment with each other than do tasks under multitasking. Threads may be distinguished only by the value of their program counters and stack pointers while sharing a single address space and set of {global variables}. There is thus very little protection of one thread from another, in contrast to multitasking. Multithreading can thus be used for very fine-grain multitasking, at the level of a few instructions, and so can hide latency by keeping the processor busy after one thread issues a long-latency instruction on which subsequent instructions in that thread depend. A light-weight process is somewhere between a thread and a full process. TL0 is an example of a threaded machine language. Dataflow computation (E.g. Id and SISAL) is an extreme form of multithreading. (1997-12-23)

Simultaneous multithreading (SMT) is a technique for improving the overall efficiency of superscalar CPUs with hardware multithreading. SMT permits multiple independent threads of execution to better use the resources provided by modern processor architectures.

In computer science, yield is an action that occurs in a computer program during multithreading, of forcing a processor to relinquish control of the current running thread, and sending it to the end of the running queue, of the same scheduling priority.

Temporal multithreading is one of the two main forms of multithreading that can be implemented on computer processor hardware, the other being simultaneous multithreading. The distinguishing difference between the two forms is the maximum number of concurrent threads that can execute in any given pipeline stage in a given cycle.

<language, compiler> A software emulator for parallel random access machine (PRAM) and a parallel Modula-2 compiler for the emulator. pm2 programming language is Modula-2/Pascal mixture having extensions for parallel execution in a PRAM. Parallelism is expressed by pardo-loop-structure. Additional features include private/shared variables, two synchronisation strategies, load balancing and parallel dynamic memory allocation. ftp://cs.joensuu.fi/pub/Software/pram/. E-mail: Simo Juvaste <sjuva@cs.joensuu.fi>. (1997-06-04)

In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system. The implementation of threads and processes differs between operating systems, but in most cases a thread is a component of a process.