Hewlett-packard Development Company, L.p.

Compaq Computer Corporation, Inc.

Compaq Information Technologies Group, L.p.

James R Kauffman

Andrew Halstead Mason

Karen Lee Noel

Paul Karl Harter, Jr

Gregory H Jordan

Stephen H Zalewski

Thomas R Benson

Stephen F Shirron

Frederick G Kleinsorge

Richard A Bishop

A method and system for ordering equitable access to a limited resource (such as a spinlock) by a plurality of contenders (such as processors) where each of the contenders contends for access more than one time. The method classifies one or more contenders that have failed to gain access to the limited resource after at least a predetermined number of attempts as abused contenders. The abused contenders attempt among themselves to gain access to the limited resource. The method repeats the above until all of the abused contenders have gained access to the limited resource.

Ensuring fairness in a multiprocessor environment using historical abuse recognition in spinlock acquisition

Multiple instances of operating systems execute cooperatively in a single multiprocessor computer wherein all processors and resources are electrically connected together. The single physical machine with multiple physical processors and resources is subdivided by software into multiple partitions, each with the ability to run a distinct copy, or instance, of an operating system. At different times, different operating system instances may be loaded on a given partition. Resources, such as CPUs and memory, can be dynamically assigned to different partitions and used by instances of operating systems running within the machine by modifying the configuration. The partitions themselves can also be changed without rebooting the system by modifying the configuration tree.

Multiprocessor computer architecture with multiple operating system instances and software controlled resource allocation

Multiple instances of operating systems execute cooperatively in a single multiprocessor computer wherein all processors and resources are electrically connected together. The single physical machine with multiple physical processors and resources is subdivided by software into multiple partitions, each with the ability to run a distinct copy, or instance, of an operating system. At different times, different operating system instances may be loaded on a given partition. Resources, such as CPUs and memory, can be dynamically assigned to different partitions and used by instances of operating systems running within the machine by modifying the configuration. The partitions themselves can also be changed without rebooting the system by modifying the configuration tree. Each instance keeps track of the CPUs in the system and their respective operational statuses relative to the instance, such as compatibility with the instance, control by the instance, and availability to the instance for SMP processing. Using separate bitvectors for the different categories, a single bit in each bitvector may be used to represent the membership of a given CPU in that particular set, and therefore in the category represented by that set.

Method and apparatus for virtual resource handling in a multi-processor computer system

Multiple instances of operating systems execute cooperatively in a single multiprocessor computer wherein all processors and resources are electrically connected together. The single physical machine with multiple physical processors and resources is subdivided by software into multiple partitions, each with the ability to run a distinct copy, or instance, of an operating system. At different times, different operating system instances may be loaded on a given partition. Resources, such as CPUs and memory, can be dynamically assigned to different partitions and used by instances of operating systems running within the machine by modifying the configuration. The partitions themselves can also be changed without rebooting the system by modifying the configuration tree. Inter-instance communication can occur in at least two different ways. In a first communication method, a single bit, which is part of a bitvector in shared memory, is modified by a first instance to indicate to a second instance that a predetermined event associated with that bit has occurred. In a second method, packetized data from the first instance is stored in shared memory, and the first instance notifies the second instance of the presence of the data. The second instance then retrieves the data and acts upon it accordingly.

Method and apparatus for communication in a multi-processor computer system

Multiple instances of operating systems execute cooperatively in a single multi-processor computer wherein a single physical machine is subdivided by software into multiple partitions, each with the ability to run a distinct copy, or instance, of an operating system. Each individual instance has the resources it needs to execute independently, but instances cooperate to migrate resources from one partition to another. The migration can be initiated and carried out under control of the operating system instances &ldquo;on the fly&rdquo; without intervention of the system administrator. Alternatively, a system administrator can reconfigure the system. Resource migration is carried out under a &ldquo;push&rdquo; model in which resources are controlled by an owning partition and must be released by that partition before they can be migrated to another partition. In accordance with this model, a first operating system instance which requires a resource must first request the resource from a second instance. In response to this request, the second instance determines whether it can spare the resource, and if so, begins to bring the resource into an idle state. The resource is actually transferred when the second instance stops using the resource.

Method and apparatus for migrating resources in a multi-processor computer system

Multiple instances of operating systems execute cooperatively in a single multiprocessor computer wherein all processors and resources are electrically connected together. The single physical machine with multiple physical processors and resources is subdivided by software into multiple partitions, each with the ability to run a distinct copy, or instance, of an operating system. At different times, different operating system instances may be loaded on a given partition. Resources, such as CPUs and memory, can be dynamically assigned to different partitions and used by instances of operating systems running within the machine by modifying the configuration. The partitions themselves can also be changed without rebooting the system by modifying the configuration tree. The system makes use of a failure protocol that results in the transfer of processing resources controlled by an instance that experiences a failure to new destination instances on other partitions. For CPUs, destination instance IDs are stored in an array which is accessed upon occurrence of a failure to determine where the CPUs will be assigned. The secondary CPUs then dump their processing contexts, and each invoke a migration routine to transfer their control to the new instances. A destination instance may be a backup instance for the instance experiencing the failure, having no processing functions prior to the failure. Thus, the processing activities of the failed instance may be resumed quickly by the backup instance.

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Nashua, NH, United States of America

James R Kauffman