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Fork–join Model
In parallel computing, the fork–join model is a way of setting up and executing parallel programs, such that execution branches off in parallel at designated points in the program, to "join" (merge) at a subsequent point and resume sequential execution. Parallel sections may fork recursively until a certain task granularity is reached. Fork–join can be considered a parallel design pattern. It was formulated as early as 1963. By nesting fork–join computations recursively, one obtains a parallel version of the divide and conquer paradigm, expressed by the following generic pseudocode: solve(problem): if problem is small enough: solve problem directly (sequential algorithm) else: for part in subdivide(problem) fork subtask to solve(part) join all subtasks spawned in previous loop return combined results Examples The simple parallel merge sort of CLRS is a fork–join algorithm. mergesort(A, lo, hi): if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fork Join
In cutlery or kitchenware, a fork (from la, furca 'pitchfork') is a utensil, now usually made of metal, whose long handle terminates in a head that branches into several narrow and often slightly curved tines with which one can spear foods either to hold them to cut with a knife or to lift them to the mouth. History Bone forks have been found in archaeological sites of the Bronze Age Qijia culture (2400–1900 BC), the Shang dynasty (c. 1600–c. 1050 BC), as well as later Chinese dynasties.Needham (2000). ''Science and Civilisation in China. Volume 6: Biology and biological technology. Part V: Fermentations and food science.'' Cambridge University Press. Pages 105–110. A stone carving from an Eastern Han tomb (in Ta-kua-liang, Suide County, Shaanxi) depicts three hanging two-pronged forks in a dining scene. Similar forks have also been depicted on top of a stove in a scene at another Eastern Han tomb (in Suide County, Shaanxi). In Ancient Egypt, large forks were used as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock (computer Science)
In computer science, a lock or mutex (from mutual exclusion) is a synchronization primitive: a mechanism that enforces limits on access to a resource when there are many threads of execution. A lock is designed to enforce a mutual exclusion concurrency control policy, and with a variety of possible methods there exists multiple unique implementations for different applications. Types Generally, locks are ''advisory locks'', where each thread cooperates by acquiring the lock before accessing the corresponding data. Some systems also implement ''mandatory locks'', where attempting unauthorized access to a locked resource will force an exception in the entity attempting to make the access. The simplest type of lock is a binary semaphore. It provides exclusive access to the locked data. Other schemes also provide shared access for reading data. Other widely implemented access modes are exclusive, intend-to-exclude and intend-to-upgrade. Another way to classify locks is by what hap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Task Parallelism
Task parallelism (also known as function parallelism and control parallelism) is a form of parallelization of computer code across multiple processors in parallel computing environments. Task parallelism focuses on distributing tasks—concurrently performed by processes or threads—across different processors. In contrast to data parallelism which involves running the same task on different components of data, task parallelism is distinguished by running many different tasks at the same time on the same data. A common type of task parallelism is pipelining, which consists of moving a single set of data through a series of separate tasks where each task can execute independently of the others. Description In a multiprocessor system, task parallelism is achieved when each processor executes a different thread (or process) on the same or different data. The threads may execute the same or different code. In the general case, different execution threads communicate with one an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MapReduce
MapReduce is a programming model and an associated implementation for processing and generating big data sets with a parallel, distributed algorithm on a cluster. A MapReduce program is composed of a ''map'' procedure, which performs filtering and sorting (such as sorting students by first name into queues, one queue for each name), and a ''reduce'' method, which performs a summary operation (such as counting the number of students in each queue, yielding name frequencies). The "MapReduce System" (also called "infrastructure" or "framework") orchestrates the processing by marshalling the distributed servers, running the various tasks in parallel, managing all communications and data transfers between the various parts of the system, and providing for redundancy and fault tolerance. The model is a specialization of the ''split-apply-combine'' strategy for data analysis. It is inspired by the map and reduce functions commonly used in functional programming,"Our abstraction is in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cilk Plus
Cilk, Cilk++, Cilk Plus and OpenCilk are general-purpose programming languages designed for multithreaded parallel computing. They are based on the C and C++ programming languages, which they extend with constructs to express parallel loops and the fork–join idiom. Originally developed in the 1990s at the Massachusetts Institute of Technology (MIT) in the group of Charles E. Leiserson, Cilk was later commercialized as Cilk++ by a spinoff company, Cilk Arts. That company was subsequently acquired by Intel, which increased compatibility with existing C and C++ code, calling the result Cilk Plus. After Intel stopped supporting Cilk Plus in 2017, MIT is again developing Cilk in the form of OpenCilk. History MIT Cilk The Cilk programming language grew out of three separate projects at the MIT Laboratory for Computer Science: * Theoretical work on scheduling multi-threaded applications. * StarTech – a parallel chess program built to run on the Thinking Machines Corporation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cilk
Cilk, Cilk++, Cilk Plus and OpenCilk are general-purpose programming languages designed for multithreaded parallel computing. They are based on the C and C++ programming languages, which they extend with constructs to express parallel loops and the fork–join idiom. Originally developed in the 1990s at the Massachusetts Institute of Technology (MIT) in the group of Charles E. Leiserson, Cilk was later commercialized as Cilk++ by a spinoff company, Cilk Arts. That company was subsequently acquired by Intel, which increased compatibility with existing C and C++ code, calling the result Cilk Plus. After Intel stopped supporting Cilk Plus in 2017, MIT is again developing Cilk in the form of OpenCilk. History MIT Cilk The Cilk programming language grew out of three separate projects at the MIT Laboratory for Computer Science: * Theoretical work on scheduling multi-threaded applications. * StarTech – a parallel chess program built to run on the Thinking Machines Corporation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Threading Building Blocks
oneAPI Threading Building Blocks (oneTBB; formerly Threading Building Blocks or TBB), is a C++ template library developed by Intel for parallel programming on multi-core processors. Using TBB, a computation is broken down into tasks that can run in parallel. The library manages and schedules threads to execute these tasks. Overview A oneTBB program creates, synchronizes, and destroys graphs of dependent tasks according to ''algorithms'', i.e. high-level parallel programming paradigms (a.k.a. Algorithmic Skeletons). Tasks are then executed respecting graph dependencies. This approach groups TBB in a family of techniques for parallel programming aiming to decouple the programming from the particulars of the underlying machine. oneTBB implements work stealing to balance a parallel workload across available processing cores in order to increase core utilization and therefore scaling. Initially, the workload is evenly divided among the available processor cores. If one core compl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OOPSLA
OOPSLA (Object-Oriented Programming, Systems, Languages & Applications) is an annual ACM research conference. OOPSLA mainly takes place in the United States, while the sister conference of OOPSLA, ECOOP, is typically held in Europe. It is operated by the Special Interest Group for Programming Languages (SIGPLAN) group of the Association for Computing Machinery (ACM). OOPSLA is an annual conference covering topics related to object-oriented programming systems, languages and applications. Like other conferences, OOPSLA offers various tracks and many simultaneous sessions, and thus has a different meaning to different people. It is an academic conference, and draws doctoral students who present peer-reviewed papers. It also draws a number of non-academic attendees, many of whom present experience reports and conduct panels, workshops and tutorials. OOPSLA has been instrumental in helping object-oriented programming develop into a mainstream programming paradigm. It has also helpe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Task Parallel Library
Parallel Extensions was the development name for a managed concurrency library developed by a collaboration between Microsoft Research and the CLR team at Microsoft. The library was released in version 4.0 of the .NET Framework. It is composed of two parts: ''Parallel LINQ'' (PLINQ) and ''Task Parallel Library'' (TPL). It also consists of a set of ''coordination data structures'' (CDS) – sets of data structures used to synchronize and co-ordinate the execution of concurrent tasks. Parallel LINQ PLINQ, or Parallel LINQ, parallelizing the execution of queries on objects (LINQ to Objects) and XML data (LINQ to XML). PLINQ is intended for exposing data parallelism by use of queries. Any computation on objects that has been implemented as queries can be parallelized by PLINQ. However, the objects need to implement the IParallelEnumerable interface, which is defined by PLINQ itself. Internally it uses TPL for execution. Task Parallel Library The Task Parallel Library (TPL) is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Concurrency
The Java programming language and the Java virtual machine (JVM) have been designed to support concurrent programming, and all execution takes place in the context of threads. Objects and resources can be accessed by many separate threads; each thread has its own path of execution but can potentially access any object in the program. The programmer must ensure read and write access to objects is properly coordinated (or " synchronized") between threads. Thread synchronization ensures that objects are modified by only one thread at a time and that threads are prevented from accessing partially updated objects during modification by another thread. The Java language has built-in constructs to support this coordination. Processes and threads Most implementations of the Java virtual machine run as a single process and in the Java programming language, concurrent programming is mostly concerned with threads (also called lightweight processes). Multiple processes can only be realize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory (LLNL) is a federal research facility in Livermore, California, United States. The lab was originally established as the University of California Radiation Laboratory, Livermore Branch in 1952 in response to the detonation of the first atomic bomb by the Soviet Union during the Cold War. It later became autonomous in 1971 and was designated a national laboratory in 1981. A federally funded research and development center, Lawrence Livermore Lab is primarily funded by the U.S. Department of Energy and it is managed privately and operated by Lawrence Livermore National Security, LLC (a partnership of the University of California), Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium (element 116) named after it. Overview LLNL is self-described as a "premier research and development institution for sci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenMP
OpenMP (Open Multi-Processing) is an application programming interface (API) that supports multi-platform shared-memory multiprocessing programming in C, C++, and Fortran, on many platforms, instruction-set architectures and operating systems, including Solaris, AIX, FreeBSD, HP-UX, Linux, macOS, and Windows. It consists of a set of compiler directives, library routines, and environment variables that influence run-time behavior. OpenMP is managed by the nonprofit technology consortium ''OpenMP Architecture Review Board'' (or ''OpenMP ARB''), jointly defined by a broad swath of leading computer hardware and software vendors, including Arm, AMD, IBM, Intel, Cray, HP, Fujitsu, Nvidia, NEC, Red Hat, Texas Instruments, and Oracle Corporation. OpenMP uses a portable, scalable model that gives programmers a simple and flexible interface for developing parallel applications for platforms ranging from the standard desktop computer to the supercomputer. An application built wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
