Abstract: An operating system for a non-uniform memory access (NUMA) multiprocessor system that utilizes a software abstraction of the NUMA system hardware representing a hierarchical tree structure to maintain the most efficient level of affinity and to maintain balanced processor and memory loads. The hierarchical tree structure includes leaf nodes representing the job processors, a root node representing at least one system resource shared by all the job processors, and a plurality of intermediate level nodes representing resources shared by different combinations of the job processors. The operating system includes a medium term scheduler for monitoring the progress of active thread groups distributed throughout the system and for assisting languishing thread groups, and a plurality of dispatchers each associated with one of the job processors for monitoring the status of the associated job processor and for obtaining thread groups for the associated job processor to execute.

Abstract: A method for handling attempts by multiple processing threads to access a shared system resource is disclosed. When a thread attempts to access a locked resource, the thread creates a description of the operation it intended to perform and stores the description on a deferred operation list associated with that resource. The deferred operation list is monitored by the thread which has control of the resource. If one or more entries is detected, the entries are removed from the list and processed by the controlling thread.