Hi and thanks for the answeg!
Ok, this sound a little Bit tricky.
Do you have any Experiemce using the OpenSource Version of Intel
Parallel Build Blocks?
I guess OpenMP is more for C layer and can parallel for loops fine but
the rest is not usefull this Time.TBB are more C++ ortiented and
supports Datastructures and Namespace replacements alternatives such as
namespace std.
Greetings Peter
Am 04.01.2012 11:28, schrieb Prof Brian Ripley:
> 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
>
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