FlushProcessWriteBuffers Test

#include <windows.h>
#include <process.h>
#include <stdio.h>
#include <intrin.h>

#define DO_FLUSH

unsigned __stdcall thread(void* p)
{
   unsigned __int64 t1 = __rdtsc();
   volatile __int64 data = 0;
   unsigned __int64 const count = 1000000000;
   for (unsigned __int64 i = 0; i != count; ++i)
   {
       data *= data;
   }
   unsigned __int64 t2 = __rdtsc();
   printf("time=%u\n", (unsigned)((t2-t1)*1000/count));
   return 0;

}

int main()
{
   HANDLE t = (HANDLE)_beginthreadex(0, 0, thread, 0,CREATE_SUSPENDED, 0);
   SetThreadAffinityMask(t, 2);
   SetThreadAffinityMask(GetCurrentThread(), 1);
   ResumeThread(t);
   unsigned __int64 tmin = 1000000000;
   unsigned __int64 tmax = 0;
   unsigned __int64 tsum = 0;
   unsigned __int64 tcount = 0;
   while (WAIT_TIMEOUT == WaitForSingleObject(t, 0))
   {
#ifdef DO_FLUSH
       unsigned __int64 t1 = __rdtsc();
       FlushProcessWriteBuffers();
       unsigned __int64 t2 = __rdtsc() - t1;
       if (t2 < tmin)
           tmin = t2;
       if (t2 > tmax)
           tmax = t2;
       tsum += t2;
       tcount += 1;
#endif
   }
   printf("min=%u, max=%u, mean=%d, count=%d\n", (unsigned)tmin,
(unsigned)tmax, tcount ? (unsigned)(tsum / tcount) : 0,
(unsigned)tcount);

}