1. A method for mapping threads or tasks to CPUs in a parallel computer, wherein at least one parallel program is running in said parallel computer which starts tasks or threads, said method comprising the steps of: providing a mapping description at runtime, wherein said mapping description specifies at least one mapping strategy of tasks or threads to CPUs; distributing said mapping description to all tasks; determining for each task or thread its assigned CPU based on said specified mapping strategy; and calling a function for binding each of said tasks or threads to its assigned CPU.