Hello Brian, exactly those reported crashes in winptrhead on thread-termination are the cause why we didn't merged it into our trunk version. Any hint on reason for it, or a testcase for debugging it are most welcome.
Regards, Kai 2012/1/4 Prof Brian Ripley <[email protected]>: > Let me have a go at answering based on my experiences. > > There is OpenMP 3 support in recent versions of gcc. But to make it > usable you need two more pieces: > > (a) libgomp to have been built with the compiler (it is optional). This > can be built statically or as a DLL: if the latter it needs to be in the > search path. > > (b) A version of pthreads. There are two available, one based on > pthreads-w32 which uses a DLL (and so needs to be in your path) and > winpthreads, part of the 'experimental' section of mingw-w64, which can > be built statically or as a DLL. > > For simply adding -fopenmp to your compile/link to work you need the > compiler configured correctly. There will be a file libgomp.spec > somewhere in the compiler tree, and it may need to be edited to be > something like > > *link_gomp: -lgomp -lpthread > > (and almost certainly will need editing if you use static linking). > > Given those pieces, all the combinations I have tried recently work > except x64 dynamic winpthreads, which is prone to crashing (most often > during process termination.) > > As far as I know both pthreads use Windows threads. In any case, the > performance can be really poor compared to say Linux as there are far > more substantial overheads. So our experience is that OpenMP is only > useful on Windows for running quite appreciable computations in > parallel. Which is not what our users use OpenMP for .... > > The reason I make the comment about DLLs is that we have seen several > instances of people compiling extensions which use OpenMP and > distributing them without the DLLs they depend on. > > These days I use my own toolchain builds, but in the past I have used > Ozhan's ('sezero') builds of gcc pre-4.5.4. He supplies pthreads-w32 > (as far as I recall you needed to unzip it). > > Brian Ripley > > On 02/01/2012 13:57, Peter Meyer wrote: >> Hi @All >> >> First: Happy New Year! >> >> In the last months i was developing a Cross Compiler Program (MinGW >> 32-Bit and Visual C/C++ 64-Bit). >> I choosed QT 4.7 - but: The MS Compiler only supports OpenMP 2.0 so the >> Code was not much efficient, >> mostly parallel for loops. The Problem at MinGW 4.5 was, thadt sometimes >> the Programm crashed because >> of a Bug in the Compiler (there was a Bug description like: OpenMP is >> broken). >> >> Ok, thadt was MinGW, now lets talk about MinGW64. How well rungs OpenMP >> 2 or higher or should i >> rethink OpenMP at all and using the OpenSource Version of Intel Thread >> Building Blocks? >> >> Greetings from Germany, >> Peter > > > -- > Brian D. Ripley, [email protected] > Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ > University of Oxford, Tel: +44 1865 272861 (self) > 1 South Parks Road, +44 1865 272866 (PA) > Oxford OX1 3TG, UK Fax: +44 1865 272595 > > ------------------------------------------------------------------------------ > Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex > infrastructure or vast IT resources to deliver seamless, secure access to > virtual desktops. With this all-in-one solution, easily deploy virtual > desktops for less than the cost of PCs and save 60% on VDI infrastructure > costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox > _______________________________________________ > Mingw-w64-public mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/mingw-w64-public -- | (\_/) This is Bunny. Copy and paste | (='.'=) Bunny into your signature to help | (")_(") him gain world domination ------------------------------------------------------------------------------ Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox _______________________________________________ Mingw-w64-public mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
