Fastest way to sort a list of number and their index

Question

I have a question that could seem very basic, but it is in a context where \"every CPU tick counts\" (this is a part of a larger algorithm that will be used on supercomputers).<

Answer 1

This will be used on supercomputers?

In that case you may want to look into parallel sorting algorithms. That will only make sense for sorting large data sets, but the win if you need it is substantial.