Fastest way to check if an array is sorted

Question

Considering there is an array returned from a function which is of very large size.

What will be the fastest approach to test if the array is sorted?

Answer 1

The only improvement i can think of is check both ends of the array at the same time, this little change will do it in half time...

public static bool IsSorted(int[] arr)
{
int l = arr.Length;
for (int i = 1; i < l/2 + 1 ; i++)
{
    if (arr[i - 1] > arr[i] || arr[l-i] < arr[l-i-1])
    {
    return false;
    }
}
return true;
}