test.cpp

mpi 测试程序

#include <cstdlib>
#include <iostream>
#include <fstream>
#include "mpi.h"
using namespace std;
const int
max_packet_size=0x1000000; //maximum size of a message
const int count=250; // numberof messages per measurement
char buff[max_packet_size]; //Send and receive buffer
int main(void) {
MPI::Init(); // initialize MPI
int rank=MPI::COMM_WORLD.Get_rank();// ascertain own rank
int size=MPI::COMM_WORLD.Get_size();// and number of
if (size==2) { // exactly two processes needed for this process
ofstream out;
if (rank==0) { // Openoutput file out.open("ping_pong.dat");
if (!out)
MPI::COMM_WORLD.Abort(EXIT_FAILURE);
out << "# Data throughput relative to packet size" << endl<< "# Time resolution"<< MPI::Wtick() << " s" << endl<< "# Packet size\tmean
time\tmaximum time" << endl;
}
// Loop through various
packet sizes
int packet_size=1;
while
(packet_size<=max_packet_size) {
double t_av=0.0;
double t_max=0.0;
// Loop through multiple
messages
for (int i=0; i<count; ++i)
{
MPI::COMM_WORLD.Barrier(); //
Sync processes
// Send and/or receive
messages
if (rank==0) {
double t=MPI::Wtime();
// Starting time
MPI::COMM_WORLD.Send(buff,packet_size, MPI::CHAR, 1, 0);
MPI::COMM_WORLD.Recv(buff,packet_size, MPI::CHAR, 1, 0);
t=(MPI::Wtime()-t)/2.0;
// Time vector
t_av+=t;
if (t>t_max)
t_max=t;
} else {
MPI::COMM_WORLD.Recv(buff,
packet_size, MPI::CHAR, 0, 0);
MPI::COMM_WORLD.Send(buff,
packet_size, MPI::CHAR, 0, 0);
}
}
if (rank==0) { // Output
results
t_av/=count;
out << packet_size <<
"\t\t" << t_av << "\t" << t_max
<< endl;
}
packet_size*=2; // Double
packet size
}
if (rank==0) // Close output
file
out.close();
}
MPI::Finalize(); // Terminate
MPI
return EXIT_SUCCESS;
}