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add runtime API to control multithreading

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This commit is contained in:
Gael Guennebaud 2010-06-10 23:30:15 +02:00
parent 842b54fe80
commit 5b192930b6
3 changed files with 50 additions and 5 deletions
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4
Eigen/src/Core/products/GeneralMatrixMatrix.h
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@ -241,8 +241,8 @@ struct ei_gemm_functor
Index sharedBlockBSize() const
{
int maxKc, maxMc;
getBlockingSizes<Scalar>(maxKc,maxMc);
Index maxKc, maxMc, maxNc;
getBlockingSizes<Scalar>(maxKc, maxMc, maxNc);
return std::min<Index>(maxKc,m_rhs.rows()) * m_rhs.cols();
}

48
Eigen/src/Core/products/Parallelizer.h
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@ -25,6 +25,50 @@
#ifndef EIGEN_PARALLELIZER_H
#define EIGEN_PARALLELIZER_H
/** \internal */
inline void ei_manage_multi_threading(Action action, int* v)
{
static int m_maxThreads = -1;
if(action==SetAction)
{
ei_internal_assert(v!=0);
m_maxThreads = *v;
}
else if(action==GetAction)
{
ei_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
{
ei_internal_assert(false);
}
}
/** \returns the max number of threads reserved for Eigen
* \sa setNbThreads */
inline int nbThreads()
{
int ret;
ei_manage_multi_threading(GetAction, &ret);
return ret;
}
/** Sets the max number of threads reserved for Eigen
* \sa nbThreads */
inline void setNbThreads(int v)
{
ei_manage_multi_threading(SetAction, &v);
}
template<typename BlockBScalar, typename Index> struct GemmParallelInfo
{
GemmParallelInfo() : sync(-1), users(0), rhs_start(0), rhs_length(0), blockB(0) {}
@ -57,10 +101,10 @@ void ei_parallelize_gemm(const Functor& func, Index rows, Index cols)
// 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(1,rows / 32);
Index max_threads = std::max<Index>(1,rows / 32);
// 3 - compute the number of threads we are going to use
Index threads = std::min<Index>(omp_get_max_threads(), max_threads);
Index threads = std::min<Index>(nbThreads(), max_threads);
if(threads==1)
return func(0,rows, 0,cols);

3
bench/bench_gemm.cpp
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@ -112,7 +112,8 @@ int main(int argc, char ** argv)
if(procs>1)
{
BenchTimer tmono;
omp_set_num_threads(1);
//omp_set_num_threads(1);
Eigen::setNbThreads(1);
BENCH(tmono, tries, rep, gemm(a,b,c));
std::cout << "eigen mono cpu " << tmono.best(CPU_TIMER)/rep << "s \t" << (double(m)*n*p*rep*2/tmono.best(CPU_TIMER))*1e-9 << " GFLOPS \t(" << tmono.total(CPU_TIMER) << "s)\n";
std::cout << "eigen mono real " << tmono.best(REAL_TIMER)/rep << "s \t" << (double(m)*n*p*rep*2/tmono.best(REAL_TIMER))*1e-9 << " GFLOPS \t(" << tmono.total(REAL_TIMER) << "s)\n";