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// Copyright (C) 2006 Trustees of Indiana University
//
// Authors: Douglas Gregor
// Andrew Lumsdaine
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// Performance test of the reduce() collective
#include <boost/mpi.hpp>
#include <boost/lexical_cast.hpp>
namespace mpi = boost::mpi;
struct add_int {
int operator()(int x, int y) const { return x + y; }
};
struct wrapped_int
{
wrapped_int() : value(0) { }
wrapped_int(int value) : value(value) { }
template<typename Archiver>
void serialize(Archiver& ar, const unsigned int /*version*/) {
ar & value;
}
int value;
};
inline wrapped_int operator+(wrapped_int x, wrapped_int y)
{
return wrapped_int(x.value + y.value);
}
namespace boost { namespace mpi {
template<> struct is_mpi_datatype<wrapped_int> : mpl::true_ { };
} }
struct serialized_int
{
serialized_int() : value(0) { }
serialized_int(int value) : value(value) { }
template<typename Archiver>
void serialize(Archiver& ar, const unsigned int /*version*/) {
ar & value;
}
int value;
};
inline serialized_int operator+(serialized_int x, serialized_int y)
{
return serialized_int(x.value + y.value);
}
int main(int argc, char* argv[])
{
mpi::environment env(argc, argv);
mpi::communicator world;
int repeat_count = 100;
int outer_repeat_count = 2;
if (argc > 1) repeat_count = boost::lexical_cast<int>(argv[1]);
if (argc > 2) outer_repeat_count = boost::lexical_cast<int>(argv[2]);
if (world.rank() == 0)
std::cout << "# of processors: " << world.size() << std::endl
<< "# of iterations: " << repeat_count << std::endl;
int value = world.rank();
int result;
wrapped_int wi_value = world.rank();
wrapped_int wi_result;
serialized_int si_value = world.rank();
serialized_int si_result;
// Spin for a while...
for (int i = 0; i < repeat_count/10; ++i) {
reduce(world, value, result, std::plus<int>(), 0);
reduce(world, value, result, add_int(), 0);
reduce(world, wi_value, wi_result, std::plus<wrapped_int>(), 0);
reduce(world, si_value, si_result, std::plus<serialized_int>(), 0);
}
for (int outer = 0; outer < outer_repeat_count; ++outer) {
// Raw MPI
mpi::timer time;
for (int i = 0; i < repeat_count; ++i) {
MPI_Reduce(&value, &result, 1, MPI_INT, MPI_SUM, 0, MPI_COMM_WORLD);
}
double reduce_raw_mpi_total_time = time.elapsed();
// MPI_INT/MPI_SUM case
time.restart();
for (int i = 0; i < repeat_count; ++i) {
reduce(world, value, result, std::plus<int>(), 0);
}
double reduce_int_sum_total_time = time.elapsed();
// MPI_INT/MPI_Op case
time.restart();
for (int i = 0; i < repeat_count; ++i) {
reduce(world, value, result, add_int(), 0);
}
double reduce_int_op_total_time = time.elapsed();
// MPI_Datatype/MPI_Op case
time.restart();
for (int i = 0; i < repeat_count; ++i) {
reduce(world, wi_value, wi_result, std::plus<wrapped_int>(), 0);
}
double reduce_type_op_total_time = time.elapsed();
// Serialized/MPI_Op case
time.restart();
for (int i = 0; i < repeat_count; ++i) {
reduce(world, si_value, si_result, std::plus<serialized_int>(), 0);
}
double reduce_ser_op_total_time = time.elapsed();
if (world.rank() == 0)
std::cout << "\nInvocation\tElapsed Time (seconds)"
<< "\nRaw MPI\t\t\t" << reduce_raw_mpi_total_time
<< "\nMPI_INT/MPI_SUM\t\t" << reduce_int_sum_total_time
<< "\nMPI_INT/MPI_Op\t\t" << reduce_int_op_total_time
<< "\nMPI_Datatype/MPI_Op\t" << reduce_type_op_total_time
<< "\nSerialized/MPI_Op\t" << reduce_ser_op_total_time
<< std::endl;
}
return 0;
}
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