Sieve C++ Parallel Programming System: Difference between revisions

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Revision as of 19:47, 17 May 2018

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==Introduction==

Sieve is a C++ compiler that will take a section of serial code, which is annotated with sieve markers, and parallelize it automatically. The programmer wraps code they wish to parallelise inside a [[lexical scope]], which is tagged as 'sieve'. Inside this scope, referred to commonly as a 'sieve block', certain rules apply [https://web.archive.org/web/20070321082311/http://www.codeplay.com/downloads_public/sievepaper-2columns-normal.pdf]:

* All [[Side effect (computer science)|side-effects]] within the sieve block are delayed until the end of the scope.

* Side-effects are defined to be any modifications to data declared outside the sieve block scope.

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The compiler will implicitly add a splitpoint above the for loop construct body, as an entry point. Similarly one will be added after as an exit point.

In the Sieve System, only local variables to the sieve block scope may have dependencies. However, these dependencies must not cross splitpoints; they will generate compiler warnings {{Citation needed|date=May 2009}}. In order to parallelize this loop, a special 'Iterator' class may be used in place of a standard integer looping counter. It is safe for parallelization, and the programmer is free to create new Iterator classes at will [http://codeplaysoftware.typepad.com/codeplay/2007/05/loop_carried_de.html]{{dead link|date=May 2018 |bot=InternetArchiveBot |fix-attempted=yes }}. In addition to these Iterator classes, the programmer is free to implement classes called 'Accumulators' which are used to carry out reduction operations.

The way the Iterator classes are implemented opens up various means for scalability. The Sieve Parallel Runtime employs dynamic [[speculative execution]] when executing on a target platform. This can yield very good speedups, however running on a single core machine can incur overheads [https://web.archive.org/web/20070827225352/http://www.codeplay.com/technology/sievebenchmarks.html].

==Determinism==

Determinism is an unusual feature of the Sieve System. If executing a parallel Sieve program on a multi core machine yields a bug, the bug will not disappear when run on a single core to aid [[debugging]][https://web.archive.org/web/20070321082311/http://www.codeplay.com/downloads_public/sievepaper-2columns-normal.pdf][http://www.cl.cam.ac.uk/~al407/research/papers/eupar07.pdf]. This has the advantage of eliminating [[race conditions]], one of the most common bugs in [[concurrent programming]]. The removal of the need to consider [[concurrency control]] structures within a sieve block can speed up development time and results in safer code.

==Supported Systems==

The system is designed for hierarchical based systems with homogeneous or heterogeneous CPU cores which have local memories, connected via DMA engines or similar memory transfer models.

Sieve has been shown [https://web.archive.org/web/20070827225352/http://www.codeplay.com/technology/sievebenchmarks.html] successfully operating on multi-core x86 systems, the [[Ageia]] [[PhysX]] [[Physics Processing Unit]], and the IBM [[Cell microprocessor]]. [[ANSI C]] is generated if a compiler [[code generator]] is not available for a certain target platform. This allows for autoparallelization using existing C compilation toolkits [http://mgrid.feis.herts.ac.uk/wp-content/scott.ppt]{{dead link|date=May 2018 |bot=InternetArchiveBot |fix-attempted=yes }}.

==See also==

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*[http://www.cl.cam.ac.uk/~al407/research/papers/eupar07.pdf Delayed Side-effects Ease Multi-core Programming] Anton Lokhmotov, Alan Mycroft, Andrew Richards. In Proceedings of the 13th International Euro-Par Conference, Rennes, France, August 2007. Lecture Notes in Computer Science 4641, 641-650, 2007.

*[http://www.cs.cmu.edu/~damp/finalPapers/lindley.pdf Implementing deterministic declarative concurrency using sieves] S. Lindley. In proceedings of DAMP 2007: Workshop on Declarative Aspects of Multicore Programming Nice, France, January 2007.

*[https://web.archive.org/web/20070321082311/http://www.codeplay.com/downloads_public/sievepaper-2columns-normal.pdf The Codeplay Sieve C++ Parallel Programming System] A. Richards. White paper, 2006.

*[http://mgrid.feis.herts.ac.uk/wp-content/scott.ppt Codeplay Sieve C++ System Presentation]{{dead link|date=May 2018 |bot=InternetArchiveBot |fix-attempted=yes }} Scott McKenzie, presented at [https://web.archive.org/web/20070217065730/http://mgrid.feis.herts.ac.uk/ MicroGrid 2006].

==External links==

*[https://web.archive.org/web/20071101113539/http://www.codeplay.com/technology/sieve.html Codeplay Sieve Website]

{{Parallel Computing}}