OpenMP support

["Jérôme M. Berger"]

scorn wrote:
> Am 06.01.2011 20:20, schrieb Iain Buclaw:
>> == Quote from scorn (scorn at d.net)'s article
>>> Am 05.01.2011 21:24, schrieb Iain Buclaw:
>>>> == Quote from Scorn (scorn at scorn.net)'s article
>>>>> I too wonder how much work it would be to support OpenMP in gdc. From
>>>>> http://www.drdobbs.com/high-performance-computing/226300277 it
>>>>> seems to be
>> that
>>>>> there is also quite a lot of magic on the compiler side (but which
>>>>> could
>>>> already
>>>>> be in the gcc parts). Maybe a concurrent garbage collector would
>>>>> also be
>> needed
>>>>> (Leandro Lucarella worked on this for his diploma thesis).
>>>>> I hope someone can help to clear this up. If not OpenMP then at
>>>>> least a
>> better
>>>>> support for multicore programming in one way or another will be really
>>>> important
>>>>> for the future of D.
>>>>
>>>> Would take just a little bit of work, yes. ;)
>>>>
>>>> Most of the heavy duty work for GCC OMP support is done by their own C
>>>> parser/internal codegen functions. So to start, will need to rewrite
>>>> half of
>> what
>>>> is there for the DMDFE AST.
>>> That really sounds tempting. Maybe we should bring this up on the main D
>>> mailing list (whatever this is (d.learn ?)) for discussion. While this
>>> might at first be a gdc only solution, having a general, developer
>>> approved official D syntax for all three compilers (dmd, gdc, ldc) would
>>> be great.
>>
>> Official syntax? Question... why? We already have pragma to perform
>> compiler-
>> independent tasks. ie:
>>
>> LDC:
>> pragma(intrinsic, "llvm.frameaddress")
>>      void* llvm_frameaddress(uint level);
>>
>> GDC:
>> pragma(attribute, optimize("-freg-struct-return"))
>>      foo getFoo();
>>
>> DMD:
>> pragma(startaddress, foo);
>>
>>
>> A typical hello world application would likely look like this:
>>
>>   void main ()
>>   {
>>     int th_id, nthreads;
>>     pragma(omp, parallel private(th_id))
>>     {
>>       th_id = omp_get_thread_num();
>>       writefln("Hello World from thread %d\n", th_id);
>>       pragma(omp, barrier)
>>       if ( th_id == 0 ) {
>>         nthreads = omp_get_num_threads();
>>         writefln("There are %d threads\n",nthreads);
>>       }
>>     }
>>   }
>>
>>
>> Regards
> 
> Oh! I didn't know this! Then, what are we waiting for ? :-)
> 
> 
> With official syntax i meant something like for example the Parallel.For
> extension of the Microsoft Parallel FX Framework (see:
> http://pietschsoft.com/post/2007/09/Parallel-FX-Library-Optimize-your-code-for-Multi-Core-machines.aspx
> for example).
> 
	You mean like this:
foreach(i; pool.parallel( iota(squares.length), 100)) {
    // Iterate over squares using work units of size 100.
    squares[i] = i * i;
}

	It is currently under review for D2:
http://cis.jhu.edu/~dsimcha/d/phobos/std_parallelism.html and
http://dsource.org/projects/scrapple/browser/trunk/parallelFuture/std_parallelism.d

		Jerome
-- 
mailto:jeberger at free.fr
http://jeberger.free.fr
Jabber: jeberger at jabber.fr

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