International Business Machines Corporation

Jay Paul Kurtz

Glen Warren Nelson

Larry J Cravens

Kenneth Charles Vossen

Kenneth Gerald Linn

Donald L Ward

Naresh Nayar

William Joseph Armstrong

Henry Joseph May

Richard Karl Kirkman

Michael Brian Brutman

Edwin C Grazier

Chris Francois

John Michael Attinella

Michael James Denney

David Ferguson Legler

Kevin L Chidester

Ryan Harvey Bishop

Dennis A Towne

An apparatus, method, and program product for optimizing a multiprocessor computing system by sampling memory reference latencies and adjusting components of the system in response thereto. During execution of processes the computing system, memory reference sampling of memory locations from shared memory of the computing system referenced in the executing processes is performed. Each sampled memory reference collected from sampling is associated with a latency and a physical memory location in the shared memory. Each sampled memory reference is analyzed to identify segments of memory locations in the shared memory corresponding to a sub-optimal latency, and based on the analyzed sampled memory references, the physical location of the one or more identified segments, the processor on which one or more processes referencing the identified segments, and/or a status associated with the one or more identified segments is dynamically adjusted to thereby optimize memory access for the multiprocessor computing system.

Dynamic process/object scoped memory affinity adjuster

A method, system and computer program product are provided for implementing feedback directed Non-Uniform Memory Access (NUMA) mitigation tuning in a computer system. During a page frame memory allocation for a process, predefined monitored performance metrics are compared with stored threshold values. Responsive to the compared values, selected use of local memory is dynamically modified during the page frame memory allocation.

Implementing feedback directed NUMA mitigation tuning

A method utilizes a virtual flight recorder to harvest a subset of events being collected by an active system tracing facility during operation of a computer system. The virtual flight recorder is 'virtual' from the sense that it is not specifically instrumented into a component with which the virtual flight recorder is associated, which eliminates the burden on developers to specifically instrument components of interest, and minimizes the impact on system performance as a result of performance metric collection.

Virtual flight recorder hosted by system tracing facility

A method, apparatus and computer program product are provided for implementing feedback directed deferral on nonessential direct access storage device (DASD) operations. A kernel DASD I/O manager maintains a queue depth count value for a DASD unit and maintains a busy flag that indicates when the queue depth count value is greater than a predefined threshold. The kernel DASD I/O manager defers optional operations responsive to the busy flag being set for the DASD unit.

Implementing feedback directed deferral of nonessential DASD operations

Diagnostic data, such as a time increment corresponding to how long a thread waits to access a shared resource, is stored within a predetermined location in a data structure, such as a hash bucket in a hash table. The location is preferably correlated to the resource such that a display of the diagnostic data may be tailored to reflect a user-specified relationship between the data and resource.

Dynamic diagnostic program for determining thread wait time

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Rochester, MN, United States of America

Jay Paul Kurtz