| // This file is part of Eigen, a lightweight C++ template library |
| // for linear algebra. |
| // |
| // Copyright (C) 2010 Gael Guennebaud <gael.guennebaud@inria.fr> |
| // |
| // This Source Code Form is subject to the terms of the Mozilla |
| // Public License v. 2.0. If a copy of the MPL was not distributed |
| // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. |
| |
| #ifndef EIGEN_PARALLELIZER_H |
| #define EIGEN_PARALLELIZER_H |
| |
| namespace Eigen { |
| |
| namespace internal { |
| |
| /** \internal */ |
| inline void manage_multi_threading(Action action, int* v) |
| { |
| static EIGEN_UNUSED int m_maxThreads = -1; |
| |
| if(action==SetAction) |
| { |
| eigen_internal_assert(v!=0); |
| m_maxThreads = *v; |
| } |
| else if(action==GetAction) |
| { |
| eigen_internal_assert(v!=0); |
| #ifdef EIGEN_HAS_OPENMP |
| if(m_maxThreads>0) |
| *v = m_maxThreads; |
| else |
| *v = omp_get_max_threads(); |
| #else |
| *v = 1; |
| #endif |
| } |
| else |
| { |
| eigen_internal_assert(false); |
| } |
| } |
| |
| } |
| |
| /** Must be call first when calling Eigen from multiple threads */ |
| inline void initParallel() |
| { |
| int nbt; |
| internal::manage_multi_threading(GetAction, &nbt); |
| std::ptrdiff_t l1, l2; |
| internal::manage_caching_sizes(GetAction, &l1, &l2); |
| } |
| |
| /** \returns the max number of threads reserved for Eigen |
| * \sa setNbThreads */ |
| inline int nbThreads() |
| { |
| int ret; |
| internal::manage_multi_threading(GetAction, &ret); |
| return ret; |
| } |
| |
| /** Sets the max number of threads reserved for Eigen |
| * \sa nbThreads */ |
| inline void setNbThreads(int v) |
| { |
| internal::manage_multi_threading(SetAction, &v); |
| } |
| |
| namespace internal { |
| |
| template<typename Index> struct GemmParallelInfo |
| { |
| GemmParallelInfo() : sync(-1), users(0), rhs_start(0), rhs_length(0) {} |
| |
| int volatile sync; |
| int volatile users; |
| |
| Index rhs_start; |
| Index rhs_length; |
| }; |
| |
| template<bool Condition, typename Functor, typename Index> |
| void parallelize_gemm(const Functor& func, Index rows, Index cols, bool transpose) |
| { |
| // TODO when EIGEN_USE_BLAS is defined, |
| // we should still enable OMP for other scalar types |
| #if !(defined (EIGEN_HAS_OPENMP)) || defined (EIGEN_USE_BLAS) |
| // FIXME the transpose variable is only needed to properly split |
| // the matrix product when multithreading is enabled. This is a temporary |
| // fix to support row-major destination matrices. This whole |
| // parallelizer mechanism has to be redisigned anyway. |
| EIGEN_UNUSED_VARIABLE(transpose); |
| func(0,rows, 0,cols); |
| #else |
| |
| // Dynamically check whether we should enable or disable OpenMP. |
| // The conditions are: |
| // - the max number of threads we can create is greater than 1 |
| // - we are not already in a parallel code |
| // - the sizes are large enough |
| |
| // 1- are we already in a parallel session? |
| // FIXME omp_get_num_threads()>1 only works for openmp, what if the user does not use openmp? |
| if((!Condition) || (omp_get_num_threads()>1)) |
| return func(0,rows, 0,cols); |
| |
| Index size = transpose ? cols : rows; |
| |
| // 2- compute the maximal number of threads from the size of the product: |
| // FIXME this has to be fine tuned |
| Index max_threads = std::max<Index>(1,size / 32); |
| |
| // 3 - compute the number of threads we are going to use |
| Index threads = std::min<Index>(nbThreads(), max_threads); |
| |
| if(threads==1) |
| return func(0,rows, 0,cols); |
| |
| Eigen::initParallel(); |
| func.initParallelSession(); |
| |
| if(transpose) |
| std::swap(rows,cols); |
| |
| Index blockCols = (cols / threads) & ~Index(0x3); |
| Index blockRows = (rows / threads) & ~Index(0x7); |
| |
| GemmParallelInfo<Index>* info = new GemmParallelInfo<Index>[threads]; |
| |
| #pragma omp parallel for schedule(static,1) num_threads(threads) |
| for(Index i=0; i<threads; ++i) |
| { |
| Index r0 = i*blockRows; |
| Index actualBlockRows = (i+1==threads) ? rows-r0 : blockRows; |
| |
| Index c0 = i*blockCols; |
| Index actualBlockCols = (i+1==threads) ? cols-c0 : blockCols; |
| |
| info[i].rhs_start = c0; |
| info[i].rhs_length = actualBlockCols; |
| |
| if(transpose) |
| func(0, cols, r0, actualBlockRows, info); |
| else |
| func(r0, actualBlockRows, 0,cols, info); |
| } |
| |
| delete[] info; |
| #endif |
| } |
| |
| } // end namespace internal |
| |
| } // end namespace Eigen |
| |
| #endif // EIGEN_PARALLELIZER_H |