Commit 746fa701 authored by Tomáš Oberhuber's avatar Tomáš Oberhuber Committed by Jakub Klinkovský
Browse files

Optimization of ParallelFor on CPU.

parent 906ef4a7

src/TNL/ParallelFor.h

+50 −11
Original line number Diff line number Diff line
@@ -37,10 +37,21 @@ struct ParallelFor 
   static void exec( Index start, Index end, Function f, FunctionArgs... args )

   {

#ifdef HAVE_OPENMP

      #pragma omp parallel for if( TNL::Devices::Host::isOMPEnabled() && end - start > 512 )

#endif

      // Benchmarks show that this is significantly faster compared

      // to '#pragma omp parallel for if( TNL::Devices::Host::isOMPEnabled() && end - start > 512 )'

      if( TNL::Devices::Host::isOMPEnabled() && end - start > 512 )

      {

#pragma omp parallel for

         for( Index i = start; i < end; i++ )

            f( i, args... );

      }

      else

         for( Index i = start; i < end; i++ )

            f( i, args... );

#else

      for( Index i = start; i < end; i++ )

         f( i, args... );

#endif

   }

};
@@ -53,11 +64,24 @@ struct ParallelFor2D 
   static void exec( Index startX, Index startY, Index endX, Index endY, Function f, FunctionArgs... args )

   {

#ifdef HAVE_OPENMP

      #pragma omp parallel for if( TNL::Devices::Host::isOMPEnabled() )

#endif

      // Benchmarks show that this is significantly faster compared

      // to '#pragma omp parallel for if( TNL::Devices::Host::isOMPEnabled() )'

      if( TNL::Devices::Host::isOMPEnabled() )

      {

#pragma omp parallel for

         for( Index i = startX; i < endX; i++ )

            for( Index j = startY; j < endY; j++ )

               f( i, j, args... );

      }

      else

         for( Index i = startX; i < endX; i++ )

            for( Index j = startY; j < endY; j++ )

               f( i, j, args... );

#else

      for( Index i = startX; i < endX; i++ )

         for( Index j = startY; j < endY; j++ )

            f( i, j, args... );

#endif

   }

};
@@ -70,12 +94,27 @@ struct ParallelFor3D 
   static void exec( Index startX, Index startY, Index startZ, Index endX, Index endY, Index endZ, Function f, FunctionArgs... args )

   {

#ifdef HAVE_OPENMP

      #pragma omp parallel for collapse(2) if( TNL::Devices::Host::isOMPEnabled() )

#endif

      // Benchmarks show that this is significantly faster compared

      // to '#pragma omp parallel for if( TNL::Devices::Host::isOMPEnabled() )'

     if( TNL::Devices::Host::isOMPEnabled() )

     {

#pragma omp parallel for collapse(2)

      for( Index i = startX; i < endX; i++ )

         for( Index j = startY; j < endY; j++ )

            for( Index k = startZ; k < endZ; k++ )

               f( i, j, k, args... );

     }

     else

         for( Index i = startX; i < endX; i++ )

            for( Index j = startY; j < endY; j++ )

               for( Index k = startZ; k < endZ; k++ )

                  f( i, j, k, args... );

#else

      for( Index i = startX; i < endX; i++ )

         for( Index j = startY; j < endY; j++ )

            for( Index k = startZ; k < endZ; k++ )

               f( i, j, k, args... );

#endif

   }

};