Unified Parallel C (UPC) is an extension of the

C programming language ''The C Programming Language'' (sometimes termed ''K&R'', after its authors' initials) is a computer programming book written by Brian Kernighan and Dennis Ritchie, the latter of whom originally designed and implemented the language, as well as ...

designed for

high-performance computing High-performance computing (HPC) uses supercomputers and computer clusters to solve advanced computation problems. Overview HPC integrates systems administration (including network and security knowledge) and parallel programming into a mult ...

on large-scale parallel machines, including those with a common global

address space In computing, an address space defines a range of discrete addresses, each of which may correspond to a network host, peripheral device, disk sector, a memory cell or other logical or physical entity. For software programs to save and retrieve st ...

( SMP and

NUMA Nuclear mitotic apparatus protein 1 is a protein that in humans is encoded by the ''NUMA1'' gene. Interactions Nuclear mitotic apparatus protein 1 has been shown to interact with PIM1, Band 4.1, GPSM2 G-protein-signaling modulator 2, also call ...

) and those with

distributed memory In computer science, distributed memory refers to a multiprocessor computer system in which each processor has its own private memory. Computational tasks can only operate on local data, and if remote data are required, the computational task mu ...

(e. g. clusters). The programmer is presented with a single

partitioned global address space In computer science, partitioned global address space (PGAS) is a parallel programming model paradigm. PGAS is typified by communication operations involving a global memory address space abstraction that is logically partitioned, where a portio ...

; where shared variables may be directly read and written by any

processor Processor may refer to: Computing Hardware * Processor (computing) **Central processing unit (CPU), the hardware within a computer that executes a program *** Microprocessor, a central processing unit contained on a single integrated circuit (I ...

, but each variable is physically associated with a single processor. UPC uses a ''single program, multiple data'' (

SPMD In computing, single program, multiple data (SPMD) is a technique employed to achieve parallelism; it is a subcategory of MIMD. Tasks are split up and run simultaneously on multiple processors with different input in order to obtain results fast ...

) model of computation in which the amount of parallelism is fixed at program startup time, typically with a single thread of execution per processor. In order to express parallelism, UPC extends ISO C 99 with the following constructs: * An explicitly parallel execution model * A shared address space ( storage qualifier) with thread-local parts (normal variables) * Synchronization primitives and a memory consistency model * Explicit communication primitives, e. g. upc_memput *

Memory management Memory management is a form of resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when ...

primitives The UPC language evolved from experiences with three other earlier languages that proposed parallel extensions to ISO C 99: AC,

Split-C Split-C is a parallel extension of the C programming language. The Split-C project website describes Split-C as: a parallel extension of the C programming language that supports efficient access to a global address space on current distributed mem ...

, and Parallel C preprocessor (PCP). UPC is not a

superset In mathematics, set ''A'' is a subset of a set ''B'' if all elements of ''A'' are also elements of ''B''; ''B'' is then a superset of ''A''. It is possible for ''A'' and ''B'' to be equal; if they are unequal, then ''A'' is a proper subset of ...

of these three languages, but rather an attempt to distill the best characteristics of each. UPC combines the programmability advantages of the shared memory programming paradigm and the control over data layout and performance of the

message passing In computer science, message passing is a technique for invoking behavior (i.e., running a program) on a computer. The invoking program sends a message to a process (which may be an actor or object) and relies on that process and its supporting i ...

programming paradigm Programming paradigms are a way to classify programming languages based on their features. Languages can be classified into multiple paradigms. Some paradigms are concerned mainly with implications for the execution model of the language, suc ...

External links

*
UPC at LBNL

UPC at GWU

GNU UPC

UPC Tutorial
(2003) {{Authority control Concurrent programming languages Parallel computing C programming language family

See also

External links