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14-510: 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

28-492: Is defined by PLINQ itself. Internally it uses TPL for execution. The Task Parallel Library ( TPL ) is the task parallelism component of the Parallel Extensions to .NET. It exposes parallel constructs like parallel For and ForEach loops, using regular method calls and delegates , thus the constructs can be used from any CLI languages . The job of spawning and terminating threads , as well as scaling

42-482: Is prevalent and only relevant when developing applications that interact with CLR implementations. Since many older programming languages have been ported to the CLR, the differentiation is needed to identify managed code, especially in a mixed setup. In this context, code that does not rely on the CLR is termed "unmanaged". A source of confusion was created when Microsoft started connecting the .NET Framework with C++ , and

56-719: The Common Language Infrastructure (CLI) specifications. With some notable exceptions, most CLI languages compile entirely to the Common Intermediate Language (CIL), an intermediate language that can be executed using the Common Language Runtime , implemented by .NET Framework , .NET Core , and Mono . Some of these languages also require the Dynamic Language Runtime (DLR). As the program

70-566: The TPL API provides methods to create the Tasks – PLINQ divides a query into smaller Tasks, and the Parallel.For , Parallel.ForEach and Parallel.Invoke methods divide a loop into Tasks. PFX includes a Task Manager object which schedules the Tasks for execution. A Task Manager contains a global queue of Tasks, which are then executed. It also encapsulates multiple threads onto which

84-420: The Tasks are executed. By default, as many threads as there are processors (or processor cores) on the system are created, though this number may be manually modified. Each thread is associated with a thread-specific queue of Tasks. When idle, each thread picks up a batch of Tasks and puts them on its local queue, where they are then executed, one by one. If the global queue is empty, a thread will look for Tasks in

98-619: The choice of how to name the Managed Extensions for C++ . It was first named Managed C++ and then renamed to C++/CLI . The creator of the C++ programming language and member of the C++ standards committee, Bjarne Stroustrup , even commented on this issue, "On the difficult and controversial question of what the CLI binding/extensions to C++ is to be called, I prefer C++/CLI as a shorthand for 'The CLI extensions to ISO C++'. Keeping C++ as part of

112-478: The execution of concurrent tasks. 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

126-499: The name reminds people what is the base language and will help keep C++ a proper subset of C++ with the C++/CLI extensions." The Microsoft Visual C++ compiler can produce both managed code, running under CLR, or unmanaged binaries, running directly on Windows. Benefits of using managed code include programmer convenience (by increasing the level of abstraction, creating smaller models) and enhanced security guarantees, depending on

140-405: The number of threads according to the number of available processors, is done by the library itself, using a work stealing scheduler. TPL also includes other constructs like Task and Future . A Task is an action that can be executed independent of the rest of the program. In that sense, it is semantically equivalent to a thread, except that it is a more light-weight object and comes without

154-479: The overhead of creating an OS thread. Tasks are queued by a Task Manager object and are scheduled to run on multiple OS threads in a thread pool when their turn comes. Future is a task that returns a result. The result is computed in a background thread encapsulated by the Future object, and the result is buffered until it is retrieved. If an attempt is made to retrieve the result before it has been computed then

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168-753: The platform (including the VM implementation). There are many historical examples of code running on virtual machines, such as the language UCSD Pascal using p-code , and the operating system Inferno from Bell Labs using the Dis virtual machine . Java popularized this approach with its bytecode executed by the Java virtual machine . Google also mention that Java and Kotlin are managed code in their Android NDK JNI documents List of CLI languages CLI languages are computer programming languages that are used to produce libraries and programs that conform to

182-607: The queues of its peers, and will take the Tasks which have been in the queue the longest ( task stealing ). When in execution, the Tasks will be executed independently, with the change in state of one Task independent of others. As a result, if they use a shared resource, they still need to be synchronized manually using locks or other constructs. Managed code Managed code is the compiler output of source code written in one of over twenty high-level programming languages , including C# , J# and Visual Basic .NET . The true and fine distinction between managed and unmanaged code

196-464: The requesting thread will block until the result is available. The other construct of TPL is Parallel class. TPL provides a basic form of structured parallelism via three static methods in the Parallel class: The main concept in the Parallel Extensions to .NET is a Task , which is a small unit of code, usually represented as a lambda function , that can be executed independently. Both PLINQ and

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