http://openmp.blogspot.com/2011/01/home.html

so i just thought of sharing it here,.. it was very helpful for me,..

You know this is a bit of a contra to what OpenMP books say - that it is best at “simple” loops. So how come this piece is slower (well with gcc it is really and i don’t know what loop it takes to b faster, for particle loops seems to b also clumsy). Any info from ur experience abt particle loops (calculating forces between particles) usin’ gcc 4.2?

My personal experience with OpenMP was that it performs well if you have very CPU-bound repetitive tasks. If you read my latest blog post I talk about how the first attempts at using [something similar to] OpenMP in EverQuest II didn’t net us any significant gains on the largest repetitive tasks we have: finding degenerate triangles, animation vertex transformations, particle system init, etc. I imagine this is true in larger projects that are doing a lot more than calculations.

I’m rather interested in Intel’s Threading Building Blocks over OpenMP for a few reasons:
- No specific compiler support/integration required
- Greater flexibility of task concepts
- Supports simple functionality of OpenMP and more
- Cross-platform
- Now Open-Source

Applying some of the principals from the TBB to the EverQuest II codebase did get us a framerate improvement of 10-15% on dual-core hardware.

Regards
Cem

I have already been looking around Compunity, and it looks quite good.
As I was reading your comment another programmer was recommending me the same book on parallel computing, so it seems I’ll have to read it :).

I’ll start any time soon with OpenMP, maybe October after my September exams, and a little rest…

Thanksa lot for all the interest and help!

For resources on OpenMP, the best place to check would be the Compunity. Look under Resources for a list of compilers and tools. Under Training you will find a list of tutorials which are good starting points.

There is a book on OpenMP called “Parallel Programming in OpenMP”, but I usually do not recommend it because it is outdated and OpenMP is not that difficult as to warrant a whole book on it (just my opinion). If you really like to have a book, I would recommend bying one on the more general subject of parallel programming, e.g. “Introduction to Parallel Computing” by Grama et. al. It has a section on OpenMP in it, as well as sections on Threads, MPI and many useful parallel algorithms. I bet there are good books on parallel programming in Spanish as well, if you prefer that and I bet some of them have sections on OpenMP in them as well.

OpenMP-support has not much todo with the architecture, but rather with the compiler and its runtime library. If the compiler supports OpenMP on a specific architecture, it will map the parallelism described by the OpenMP-directives to the native thread library provided by the operating system (e.g. POSIX threads or win32 threads). So if you have a compiler for a specific architecture that supports OpenMP, you are set to compile and run OpenMP programs there. For a list of compilers supporting OpenMP see the Compunity page of compilers.

As soon as GCC 4.2 with OpenMP-support is released, I do not know of any major architecture that OpenMP does not support (since GCC basically runs everywhere ).

Hope that helps!

Willing to read more and more of this stuff.

Thanks!