cp.c

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

int main() {
    int nloop = 1024, i;
    LARGE_INTEGER freq, t0, t1;

    QueryPerformanceFrequency(&freq);

    QueryPerformanceCounter(&t0);
    for (i=0; i<nloop; i++) {

        STARTUPINFO sp = {0};
        PROCESS_INFORMATION pi;

        sp.cb = sizeof(sp);

        CreateProcess(TEXT("exit2.exe"),
                      TEXT(""),
                      NULL,
                      NULL,
                      FALSE,
                      0,
                      NULL,
                      NULL,
                      &sp,
                      &pi);

        CloseHandle(pi.hThread);
        WaitForSingleObject(pi.hProcess, INFINITE);

        CloseHandle(pi.hProcess);
    }
    QueryPerformanceCounter(&t1);

    printf("%f\n", (t1.QuadPart-t0.QuadPart) / ((double)(freq.QuadPart)*nloop));

    return 0;
}