5. Seminar - Parallel programming for SMS (C language + OpenMP)

  LARGE_INTEGER start, stop, frequency;
  long overhead;
  QueryPerformanceFrequency(&frequency);
  QueryPerformanceCounter(&start);
  QueryPerformanceCounter(&stop);
  overhead = stop.QuadPart-start.QuadPart;
 
  //------------------------------
  QueryPerformanceCounter(&start);
  // ...
  QueryPerformanceCounter(&stop);
  //------------------------------
 
  cout << " Execution time of observed program portion is "
       << 1000*(stop.QuadPart - start.QuadPart - overhead)/(double)frequency.QuadPart
       << " ms" << endl;

    struct timespec start, stop;
    double elapsed;
 
    //------------------------------
    clock_gettime(CLOCK_REALTIME, &start);
    // ...
    clock_gettime(CLOCK_REALTIME, &stop);
    //------------------------------
 
    elapsed = ( stop.tv_sec - start.tv_sec )*1000
             + (double)( stop.tv_nsec - start.tv_nsec )/(double)1000000;
    printf( " Execution time of observed program portion is %lf ms\n", elapsed);

It is necessary to add path to Cygwin binaries to executables search path %PATH%. It can be done by next command in command line: setx path “%path%;C:\Cygwin

MPI executables directory neds to be added to search path as well: setx path ”%path%;C:\Program Files (x86)\MPICH2\bin

Option setup in NetBeans IDE:
Tools → Options → C/C++ → karta “Build Tools” → Tool Collection → Add.. → Cygwin
Tools → Options → C/C++ → karta “Code Assistance” → Tool Collection → Cygwin
and insert MPICH2 in Include directories list: C:\Program Files (x86)\MPICH2\include

On the “Build Tools” tab in the same dialog (Tools → Options → C/C++) next setup should be seen:

• Base Director: C:\Cygwin\bin
• C compiler C:\Cygwin\bin\gcc.exe
• C++ Compiler: C:\Cygwin\bin\g++-3.exe
• Assembler: C:\cygwin\bin\as.exe
• Make Command: C:\Cygwin\bin\make.exe
• Debugger: C:\Cygwin\bin\gdb.exe

OpenMP:
File → Project Properties:

C Compiler:
  - Additional Options: -fopenmp

---

MPI:
File → Project Properties:

C Compiler:
  - Include directories: .../Program Files/MPICH2/include
Linker:
  - Additional Library directories: .../Program Files/MPICH2/lib
  - Libraries: mpi.lib

---

OpenMP & MPI:
File → Project Properties:

C Compiler:
  - Include directories: .../Program Files/MPICH2/include
  - Additional Options: -fopenmp
Linker:
  - Additional Library directories: .../Program Files/MPICH2/lib
  - Libraries: mpi.lib

OpenMP:

g++ program.c -fopenmp

---

MPI:

g++ program.c -I"C:\Program Files\MPICH2\include" -L"C:\Program Files\MPICH2\lib"  -lmpi

---

OpenMP & MPI:

g++ program.c -fopenmp -I"C:\Program Files\MPICH2\include" -L"C:\Program Files\MPICH2\lib"  -lmpi

OpenMP:

#include <stdio.h>
#include <omp.h>
 
int main(int argc, char *argv[]) {
  int iam = 0, np = 1;
 
 #pragma omp parallel default(shared) private(iam, np)
  {
    np = omp_get_num_threads();
    iam = omp_get_thread_num();
    printf("Hello from thread %d out of %d \n", iam, np);
  }
 
  return 0;
}

---

MPI:

#include <stdio.h>
#include "mpi.h"
 
int main(int argc, char *argv[]) {
  int numprocs, rank, namelen;
  char processor_name[MPI_MAX_PROCESSOR_NAME];
 
  MPI_Init(&argc, &argv);
  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  MPI_Get_processor_name(processor_name, &namelen);
 
  printf("Hello from process %d out of %d on %s\n",
          rank, numprocs, processor_name);
 
  MPI_Finalize();
  return 0;
}

---

OpenMP & MPI:

#include <stdio.h>
#include "mpi.h"
#include <omp.h>
 
int main(int argc, char *argv[]) {
  int numprocs, rank, namelen;
  char processor_name[MPI_MAX_PROCESSOR_NAME];
  int iam = 0, np = 1;
 
  MPI_Init(&argc, &argv);
  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  MPI_Get_processor_name(processor_name, &namelen);
 
 #pragma omp parallel default(shared) private(iam, np)
  {
    np = omp_get_num_threads();
    iam = omp_get_thread_num();
    printf("Hello from thread %d out of %d from process %d out of %d on %s\n",
           iam, np, rank, numprocs, processor_name);
  }
 
  MPI_Finalize();
  return 0;
}