International Business Machines Corporation

Lynn Keat Chung

Richard Karl Kirkman

Don Darrell Reed

Kenneth Charles Vossen

Henry Joseph May

Patrick Joseph McCarthy

Mark Robert Funk

Christopher Francois

Chistopher Francois

Angela Mae Newton

Michael Joseph Corrigan

Edwin C Grazier

Mark Gregory Manges

Mark Philip Piazza

Arlys Jean Leitzen

Shiun Lee

Disclosed is an apparatus, method, and program product for identifying and grouping threads that have interdependent data access needs. The preferred embodiment of the present invention utilizes two different constructs to accomplish this grouping. A Memory Affinity Group (MAG) is disclosed. The MAG construct enables multiple threads to be associated with the same node without any foreknowledge of which threads will be involved in the association, and without any control over the particular node with which they are associated. A Logical Node construct is also disclosed. The Logical Node construct enables multiple threads to be associated with the same specified node without any foreknowledge of which threads will be involved in the association. While logical nodes do not explicitly identify the underlying physical nodes comprising the system, they provide a means of associating particular threads with the same node and other threads with other node(s).

Reducing remote memory accesses to shared data in a multi-nodal computer system

An apparatus, program product and method in which application program-specified resource allocation and allocation strength preferences are used to allocate hardware resources from a computer for that application program. The resource allocation preference is used to allocate hardware resources for the application program, while the allocation strength preference is used to determine whether to allocate alternate hardware resources when the resource allocation preference specified by the application program cannot be met.

Resource allocation in a NUMA architecture based on application specified resource and strength preferences for processor and memory resources

Resource allocation in a NUMA architecture based on separate application specified resource and strength preferences for processor and memory resources

Mechanism for reducing remote memory accesses to shared data in a multi-nodal computer system

Disclosed is an apparatus, method, and program product that enables distribution of operating system resources on a nodal basis in the same proportions as the expected system workload. The preferred embodiment of the present invention accomplishes this by assigning various types of weights to each node to represent their proportion of the overall balance within the system. Target Weights represent the desired distribution of the workload based on the existing proportions of processor and memory resources on each node. The actual workload balance on the system is represented by Current Weights, which the operating system strives to keep as close to the Target Weights as possible, on an ongoing basis. When the system is started, operating system services distribute their resources nodally in the same proportions as the Target Weights, and can request to be notified if the Target Weights ever change. If processors and/or memory are subsequently added or removed, new Target Weights are calculated at that time, and all services which requested notification are notified so they can redistribute their resources according to the new Target Weights or a stepwise refinement thereof.

Mechanism for enabling the distribution of operating system resources in a multi-node computer system

Disclosed is an apparatus, method, and program product for observing the nodal workload balance of the system on an ongoing basis, and for dynamically changing the preferred nodes of existing threads in order to improve nodal balance. Workload balance is ascertained on a nodal basis and then thread-based workload information is collected. If the detected imbalance persists, the thread-based information is used to change the assignment of preferred nodes to threads to improve nodal workload balance.

Mechanism for dynamic workload rebalancing in a multi-nodal computer system

When a computer system is upgraded, such as by adding a more advanced processor chip and/or a new operating system, a different page size may be employed. The page size is altered for data previously stored in a storage medium such as a hard disk in the computer system, without removing all of the data from the medium and rewriting it. Data is stored in the medium in blocks or sectors which have headers defining the block. Also, tables define memory objects and segments, and locate virtual memory addresses in physical memory. The headers and/or tables can be changed without rewriting all of the data in the sectors or pages in physical memory, so the page size is changed to accommodate the new system components, without excessive burden on system hardware or undue expenditure of time. In an example, in changing from a CISC processor with a 512-byte page size to a RISC system with a 4K-byte page size, the segments are changed to always be of a size of an integral multiple of 4K, and 'extents' or subdivisions within a segment are changed to be multiples of 4K. Any excess space generated by these changes is zeroed. After alteration, the media (such as disks) can be accessed by either the CISC system or the new upgraded RISC system.

Changing page size in storage media of computer system

Growing community of inventors

Rochester, MN, United States of America

Lynn Keat Chung