|allocation in hierarchy|
A homogenous multiprocesssor is consedered. In conventional computers hierarchies have been used for communication links and memories, but not for processors.
These hierarchies have been easily understood - they are, however, more complicated in multiprocessors.
With a hierarchy is ment a number of processors communicating with one memory module being cheaper, larger and generally slower than the memories of the processors.
The access of the memory increases the communication. A nead to read the memory results in a latency time during which data must be stored. Thus there is nead for more local memory.
What data should be stored in a secondary memory? In a conventional processor data is stored in the stack, there is a natural order, that a cache memory handles pretty well. In a multiprocessor the requests are almost random and not at all suited for a cache.
One way to solve this is to add "queue calculations" - ie no execution at all but only intermediate storing. They are executed in special processors being nothing but secondary memories. If this is possible the normal resource theory could be used for a slightly modified allacation algorithm.
Allocation algorithms for such systems are studied.