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In this post we will continue to introduce you into OpenMP technology and tell you about some functions and new directives.»
Now we would like to start introducing you into OpenMP technology and show you the ways of using it.»
Programmers see in C++0x standard an opportunity to use lambda-functions and other entities I do not quite understand :).»
This paper contains some questions and answers about PVS-Studio code analyzer by OOO "Program Verification Systems".»
This paper contains some questions and answers about VivaCore C/C++ code analysis library by OOO "Program Verification Systems"»
The article describes and demonstrates by an example the use of PVS-Studio 3.40 new function "Mark as False Alarm". »
Terminology
OpenMP
OpenMP. OpenMP is a standard of programming on scaling SMP-systems (SSMP, ccNUMA etc) in the shared memory model. In the shared memory programming model all the processes use the common address space which they asynchronously address with reading and writing requests. OpenMP standard includes specifications of the set of the compiler's directives and the environment's functions and variables. Development of OpenMP specification is performed by several large hardware and software manufacturers whose work is regulated by a non-commercial organization called OpenMP Architecture Review Board (ARB). The main purpose of creating OpenMP was to set programmers free from multi-thread complexity allowing them to focus on more important high-level issues. The main OpenMP advantages are:
"Incremental paralleling" of a program. OpenMP is an ideal for the developers who want to quickly parallel their calculating programs with large parallel loops. A developer does not create a new parallel program but simply sequentially adds OpenMP-directives into the text of a sequential program.
An OpenMP-program can be used as a sequential program on a single-processor platform, that is there is no need to support both the sequential and parallel versions.
Good portability. If the compiler does not even support OpenMP-directives, it still will compile a workable program which will be executed sequentially.
One of OpenMP's advantages is also support of so called "orphan" (separated) directives, that is directives of synchronizing and distributing work may not directly be included into the lexical context of the parallel area.
Parallel software development is not only a difficult algorithmic task. Parallel software is also difficult to test because errors in such programs occur irregularly and fail to be recalled. One of the methods of searching errors in parallel programs is to use static analyzers that work with the source code and do not depend on the execution environment.
Our company OOO "Program Verification Systems" developed the static code analyzer VivaMP (included into PVS-Studio) intended for detecting errors in parallel applications based on OpenMP technology. VivaMP static analyzer allows you to test C/C++ code and is an add-on to Visual Studio 2005/2008 environment. The analyzer allows you to find many errors providing the range of diagnosis from inefficient constructions to race conditions.
References
- Wikipedia. OpenMP
- OpenMP specification
- Kang Su Gatlin and Pete Isensee. OpenMP and C++
- Richard Gerber. Getting Started with OpenMP