Centre Blaise Pascal » Bench4GPU

/* Simple SillySum function in C and OpenMP/C */

/* compilation with : gcc -O3 -fopenacc -foffload=nvptx-none -foffload="-O3 -misa=sm_35 -lm" -o MySteps_openacc MySteps_openacc.c -lm */

#include <math.h>

#include <stdio.h>

#include <stdlib.h>

#include <sys/time.h>

#define PI 3.141592653589793

#define MYFLOAT float

#pragma acc routine

MYFLOAT MySillyFunction(MYFLOAT x)

{

    return(pow(sqrt(log(exp(atanh(tanh(asinh(sinh(acosh(cosh(atan(tan(asin(sin(acos(cos(x))))))))))))))),2)); 

}

void MySillySum(MYFLOAT *res, MYFLOAT *a, MYFLOAT *b,int calls, int size)

{

  for (uint i=0; i<size;i++) 

    {

      MYFLOAT ai=a[i];

      MYFLOAT bi=b[i];

      for (int c=0;c<calls;c++)

        {

          ai=MySillyFunction(ai);

          bi=MySillyFunction(bi);

        }

      res[i] = ai + bi;

    }

}

void MySillySumOpenACC(MYFLOAT *res, MYFLOAT *a, MYFLOAT *b,int calls, int size)

{

  #pragma acc data copyin(a[0:size],b[0:size]),copyout(res[0:size])

  #pragma acc parallel loop

  for (uint i=0; i<size;i++) 

    {

      MYFLOAT ai=a[i];

      MYFLOAT bi=b[i];

      for (int c=0;c<calls;c++)

        {

          ai=MySillyFunction(ai);

          bi=MySillyFunction(bi);

        }

      res[i] = ai + bi;

    }

}

MYFLOAT MyNorm(MYFLOAT *a,MYFLOAT *b,int size)

{

  MYFLOAT norm=0.;

  for (int i=0;i<size;i++)

    {

      norm+=pow(a[i]-b[i],2);

    }

  return(sqrt(norm));

}

void MyPrint(MYFLOAT *a,int size)

{

  printf("[");

  for (int i=0;i<size;i++)

    {

      printf(" %.8e ",a[i]);

    }

  printf("]\n");

}

int main(int argc,char *argv[])

{

  float *a,*b,*res,*resacc;

  int size=1024;

  int calls=1;

  struct timeval tv1,tv2;

  if (argc > 1) {

    size=(int)atoll(argv[1]);

    calls=(int)atoll(argv[2]);

  }

  else {

    printf("\n\tPi : Estimate SillySum\n\n\t\t#1 : size (default 1024)\n\t\t#2 : calls (default 1)\n\n");

  }

  printf("%i %i\n",size,calls);

  a=(float*)malloc(size*sizeof(MYFLOAT));

  b=(float*)malloc(size*sizeof(MYFLOAT));

  res=(float*)malloc(size*sizeof(MYFLOAT));

  resacc=(float*)malloc(size*sizeof(MYFLOAT));

  srand(110271);

  for (int i=0;i<size;i++)

    {

      a[i]=(MYFLOAT)rand()/(MYFLOAT)RAND_MAX;

      b[i]=(MYFLOAT)rand()/(MYFLOAT)RAND_MAX;

      res[i]=0.;

      resacc[i]=0.;

    }

  gettimeofday(&tv1, NULL);

  MySillySum(res,a,b,calls,size);

  gettimeofday(&tv2, NULL);

  MYFLOAT elapsed=(MYFLOAT)((tv2.tv_sec-tv1.tv_sec) * 1000000L +

                            (tv2.tv_usec-tv1.tv_usec))/1000000;

  gettimeofday(&tv1, NULL);

  MySillySumOpenACC(resacc,a,b,calls,size);

  gettimeofday(&tv2, NULL);

  MYFLOAT elapsedAcc=(MYFLOAT)((tv2.tv_sec-tv1.tv_sec) * 1000000L +

                               (tv2.tv_usec-tv1.tv_usec))/1000000;

  MYFLOAT MyChecker=MyNorm(res,resacc,size);

  printf("Norm: %.8e\n",MyChecker);

#ifdef VERBOSE

  MyPrint(res,size);

  MyPrint(resacc,size);

#endif

  printf("Elapsed Time: %.3f\n",elapsed);

  printf("OpenACC Elapsed Time: %.3f\n",elapsedAcc);

  printf("NaiveRate: %.i\n",(int)((float)size/elapsed));

  printf("OpenACCRate: %.i\n",(int)((float)size/elapsedAcc));

  printf("OpenACCRatio: %.3f\n",elapsed/elapsedAcc);

  free(a);

  free(b);

  free(res);

  free(resacc);

}