membench.c

#include <stdio.h>
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>

#if defined(__i386__)

static __inline__ unsigned long long rdtsc(void)
{
  unsigned long long int x;
     __asm__ volatile (".byte 0x0f, 0x31" : "=A" (x));
     return x;
}
#elif defined(__x86_64__)


static __inline__ unsigned long long rdtsc(void)
{
  unsigned hi, lo;
  __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
  return ( (unsigned long long)lo)|( ((unsigned long long)hi)<<32 );
}

#elif defined(__powerpc__)


static __inline__ unsigned long long rdtsc(void)
{
  unsigned long long int result=0;
  unsigned long int upper, lower,tmp;
  __asm__ volatile(
                "0:                  \n"
                "\tmftbu   %0           \n"
                "\tmftb    %1           \n"
                "\tmftbu   %2           \n"
                "\tcmpw    %2,%0        \n"
                "\tbne     0b         \n"
                : "=r"(upper),"=r"(lower),"=r"(tmp)
                );
  result = upper;
  result = result<<32;
  result = result|lower;

  return(result);
}

#endif

#define N (1024*64)

int main(int argc, char* argv[])
{
  unsigned long long a,b;
  unsigned long long min,max;
  char* p;
  int i;

  p = (char*)malloc(N);
  assert( p!=(char*)0 );

  max = 0;
  min = UINT64_MAX;

  for(i=0; i<N; i++ ) {
    a = rdtsc();
    p[i] = 0;
    b = rdtsc() - a;
    //if(i%(1024) == 0) 
            printf("%d\t%llu\n", i, b);
    if( b > max ) max = b;
    else if( b < min ) min = b;
  }
  printf("min=%llu\n", min);
  printf("max=%llu\n", max);
  free(p);
  return 0;
}