International Business Machines Corporation

Richard Lindsley

Wayne Alan Downer

Steven R Carbonari

Tasks are assigned to processors of a system. The resident set size of each task is determined, specifying the amount of physical information allocated thereto, and locational information of this memory with respect to the processors is determined. Each task is assigned one processor, based on the task's resident set size, and the locational information of the task's allocated physical memory. Each task is attempted to be assigned to the processor closest to the largest portion of the physical memory allocated thereto. A number of the tasks may be determined as best suited to run on a given processor, but the given processor may be unable to run them all. The processor may be thus assigned only those tasks that have a greatest amount of physical memory allocated that is closest to the processor, such as the greatest amount or percentage of physical memory allocated that is local to the processor.

Assigning tasks to processors based at least on resident set sizes of the tasks

Computer-based devices, whether initiators or targets, are assured access to a bus having a fixed priority arbitration scheme (such as a SCSI bus) by assigning to each initiator a &ldquo;fair share&rdquo; of the bus bandwidth. This share is defined as a number of bytes per a unit of time such as a time period. The shares together total a fraction of the total bus bandwidth, with a margin of bus bandwidth left unassigned. To prevent initiator starvation, each initiator monitors its bus requests to determine if it is being prevented by higher-priority initiators from using its assigned share of the bandwidth. If not, the initiator periodically pings each higher-priority initiator to indicate that it is not being starved. So long as a higher-priority initiator continues to receive pings from all lower-priority initiators, the higher-priority initiator can continue to use as much bandwidth as it needs. If the higher-priority initiator fails to receive a ping from a lower-priority initiator, it stops sending new bus requests to the SCSI bus, making the bandwidth available to the lower-priority initiator. To prevent target starvation, each initiator monitors its outstanding bus requests to targets. If a request does not complete in an appropriate time, the initiator pings all other initiators with notification of target starvation. In response, all initiators limit their new bus requests to their share of the bandwidth. This limiting makes the unassigned margin of bus bandwidth available to the targets.

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Aloha, OR, United States of America

Richard Lindsley