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Multithreading (computer Architecture)
In computer architecture, multithreading is the ability of a central processing unit (CPU) (or a single core in a multi-core processor) to provide multiple threads of execution. Overview The multithreading paradigm has become more popular as efforts to further exploit instruction-level parallelism have stalled since the late 1990s. This allowed the concept of throughput computing to re-emerge from the more specialized field of transaction processing. Even though it is very difficult to further speed up a single thread or single program, most computer systems are actually multitasking among multiple threads or programs. Thus, techniques that improve the throughput of all tasks result in overall performance gains. Two major techniques for throughput computing are ''multithreading'' and ''multiprocessing''. Advantages If a thread gets a lot of cache misses, the other threads can continue taking advantage of the unused computing resources, which may lead to faster overall exe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multithreaded Process
Multithreading may refer to: * Multithreading (computer architecture) In computer architecture, multithreading is the ability of a central processing unit (CPU) (or a single core in a multi-core processor) to provide multiple threads of execution. Overview The multithreading paradigm has become more popular a ..., in computer hardware * Multithreading (software), in computer software {{Disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multitasking Of Computer Programs
In computing, multitasking is the concurrent computing, concurrent execution of multiple tasks (also known as Process (computing), processes) over a certain period of time. New tasks can interrupt already started ones before they finish, instead of waiting for them to end. As a result, a computer executes segments of multiple tasks in an interleaved manner, while the tasks share common processing resources such as central processing units (CPUs) and main memory. Multitasking automatically interrupts the running program, saving its state (partial results, memory contents and computer register contents) and loading the saved state of another program and transferring control to it. This "context switch" may be initiated at fixed time intervals (pre-emptive multitasking), or the running program may be coded to signal to the supervisory software when it can be interrupted (cooperative multitasking). Multitasking does not require Parallel computing, parallel execution of multiple task ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha 21464
The Alpha 21464 is an unfinished microprocessor that implements the Alpha instruction set architecture (ISA) developed by Digital Equipment Corporation and later by Compaq after it acquired Digital. The microprocessor was also known as EV8 (codenamed Araña). Slated for a 2004 release, it was canceled on 25 June 2001 when Compaq announced that Alpha would be phased out in favor of Itanium by 2004. When it was canceled, the Alpha 21464 was at a late stage of development but had not been taped out. The 21464's origins began in the mid-1990s when computer scientist Joel Emer was inspired by Dean Tullsen's research into simultaneous multithreading (SMT) at the University of Washington. Emer had researched the technology in the late 1990s and began to promote it once he was convinced of its value. Compaq made the announcement that the next Alpha microprocessor would use SMT in October 1999 at Microprocessor Forum 1999. At that time, it was expected that systems using the Alpha 21464 wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compaq
Compaq Computer Corporation was an American information technology, information technology company founded in 1982 that developed, sold, and supported computers and related products and services. Compaq produced some of the first IBM PC compatible computers, being the second company after Columbia Data Products to legally Reverse engineering, reverse engineer the BIOS of the IBM Personal Computer. It rose to become the Market share of personal computer vendors, largest supplier of PC systems during the 1990s. The company was initially based in Harris County, Texas. The company was formed by Rod Canion, Jim Harris (entrepreneur), Jim Harris, and Bill Murto, all of whom were former Texas Instruments senior managers. All three had left by 1991 under a shakeup, which saw Eckhard Pfeiffer appointed president and CEO, serving through the 1990s. Benjamin M. Rosen, Ben Rosen provided the venture capital financing for the fledgling company and served as chairman of the board for 17 years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Equipment Corporation
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until he was forced to resign in 1992, after the company had gone into precipitous decline. The company produced many different product lines over its history. It is best known for the work in the minicomputer market starting in the early 1960s. The company produced a series of machines known as the Programmed Data Processor, PDP line, with the PDP-8 and PDP-11 being among the most successful minis in history. Their success was only surpassed by another DEC product, the late-1970s VAX "supermini" systems that were designed to replace the PDP-11. Although a number of competitors had successfully competed with Digital through the 1970s, the VAX cemented the company's place as a leading vendor in the computer space. As microcomputers improved in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Multithreading
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. In temporal multithreading the number is one, while in simultaneous multithreading the number is greater than one. Some authors use the term super-threading synonymously. Variations There are many possible variations of temporal multithreading, but most can be classified into two sub-forms: ; Coarse-grained: The main processor pipeline contains only one thread at a time. The processor must effectively perform a rapid context switch before executing a different thread. This fast context switch is sometimes referred to as a ''thread switch''. There may or may not be additional penalty cycles when switching. :There are many possible variations of coa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superscalar Processor
A superscalar processor (or multiple-issue processor) is a CPU that implements a form of parallelism called instruction-level parallelism within a single processor. In contrast to a scalar processor, which can execute at most one single instruction per clock cycle, a superscalar processor can execute or start executing more than one instruction during a clock cycle by simultaneously dispatching multiple instructions to different execution units on the processor. It therefore allows more throughput (the number of instructions that can be executed in a unit of time which can even be less than 1) than would otherwise be possible at a given clock rate. Each execution unit is not a separate processor (or a core if the processor is a multi-core processor), but an execution resource within a single CPU such as an arithmetic logic unit. While a superscalar CPU is typically also pipelined, superscalar and pipelining execution are considered different performance enhancement techniq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stave (wood)
] A stave is a narrow length of wood with a slightly bevelled edge to form the sides of barrels, tanks, tubs, vats and pipelines, originally handmade by coopers. They have been used in the construction of large holding tanks and penstocks at hydro power developments. They are also used in the construction of certain musical instruments with rounded bodies or backs. See also * Rubicon Hydroelectric Scheme, which has wood stave penstocks on operating power stations *Lake Margaret Power Station The Lake Margaret Power Stations comprise two hydroelectric power stations located in Western Tasmania, Australia. The power stations are part of the King Yolande Power Scheme and are owned and operated by Hydro Tasmania. Officially the Upper ..., which had a wood stave penstock replaced in 2010 References Structural engineering Woodworking {{civil-engineering-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preemption (computing)
In computing, preemption is the act performed by an external scheduler — without assistance or cooperation from the task — of temporarily interrupting an executing task, with the intention of resuming it at a later time. This preemptive scheduler usually runs in the most privileged protection ring, meaning that interruption and then resumption are considered highly secure actions. Such changes to the currently executing task of a processor are known as context switching. User mode and kernel mode In any given system design, some operations performed by the system may not be preemptable. This usually applies to kernel functions and service interrupts which, if not permitted to run to completion, would tend to produce race conditions resulting in deadlock. Barring the scheduler from preempting tasks while they are processing kernel functions simplifies the kernel design at the expense of system responsiveness. The distinction between user mode and kernel mode, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pipeline (computing)
In computing, a pipeline, also known as a data pipeline, is a set of data processing elements connected in series, where the output of one element is the input of the next one. The elements of a pipeline are often executed in parallel or in time-sliced fashion. Some amount of buffer storage is often inserted between elements. Concept and motivation Pipelining is a commonly used concept in everyday life. For example, in the assembly line of a car factory, each specific task—such as installing the engine, installing the hood, and installing the wheels—is often done by a separate work station. The stations carry out their tasks in parallel, each on a different car. Once a car has had one task performed, it moves to the next station. Variations in the time needed to complete the tasks can be accommodated by "buffering" (holding one or more cars in a space between the stations) and/or by "stalling" (temporarily halting the upstream stations), until the next station becomes avai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Dependency
A data dependency in computer science is a situation in which a program statement (instruction) refers to the data of a preceding statement. In compiler theory, the technique used to discover data dependencies among statements (or instructions) is called dependence analysis. Description Assuming statement S_1 and S_2, S_2 depends on S_1 if: :\left (S_1) \cap O(S_2)\right\cup \left (S_1) \cap I(S_2)\right\cup \left (S_1) \cap O(S_2)\right\neq \varnothing where: * I(S_i) is the set of memory locations read by * O(S_j) is the set of memory locations written by and * there is a feasible run-time execution path from S_1 to These conditions are called Bernstein's Conditions, named after Arthur J. Bernstein. Three cases exist: * Anti-dependence: I(S_1) \cap O(S_2) \neq \varnothing, S_1 \rightarrow S_2 and S_1 reads something before S_2 overwrites it * Flow (data) dependence: O(S_1) \cap I(S_2) \neq \varnothing, S_1 \rightarrow S_2 and S_1 writes before something read by S_2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Context Switch
In computing, a context switch is the process of storing the state of a process or thread, so that it can be restored and resume execution at a later point, and then restoring a different, previously saved, state. This allows multiple processes to share a single central processing unit (CPU), and is an essential feature of a multiprogramming or multitasking operating system. In a traditional CPU, each process – a program in execution – uses the various CPU registers to store data and hold the current state of the running process. However, in a multitasking operating system, the operating system switches between processes or threads to allow the execution of multiple processes simultaneously. For every switch, the operating system must save the state of the currently running process, followed by loading the next process state, which will run on the CPU. This sequence of operations that stores the state of the running process and loads the following running process is called a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
