International Business Machines Corporation

Timothy Joseph Torzewski

William Joseph Armstrong

Gregory Michael Nordstrom

Gary Ross Ricard

Michael Joseph Corrigan

Naresh Nayar

John Ronald Oberly, Iii

Sean Thomas Brownlow

Steven Mark Thurber

Mark Robert Funk

John Thomas O'Quin, Ii

James Arthur Lindeman

Robert Carl Seemann

Theresa Renee Euler

Arthur Douglas Smet

Donald Arthur Morrison

William Joseph Armstrong, Jr

Robert Anthony Petrillo

Larry Keith McMains

William J Armstrong, Jr

A method of managing memory may include selecting an object of a memory heap to be de-allocated and initiating a deferred lock configured to delay de-allocation of the object. The deferred lock may be acquired in response to a thread leaving a computing space, and the object may be de-allocated.

Iteratively de-allocating active objects associated with virtual functions of an adapter

A method of configuring system memory may include determining a plurality of memory regions supportable on an input/output adapter. The input/output adapter may include a physical function. A memory region of the plurality of memory regions may be allocated to the physical function when an address of the physical function is unknown. The method may further include determining the address of the physical function and associating the address of the physical function with the memory region.

Allocating addressable memory regions to an adapter

An apparatus, program product and method dynamically bind Message Signaled Interrupt (MSI) resources shared by a plurality of clients to an interrupt facility in an MSI-capable computer. In addition, management of such bindings may be implemented using a platform independent interrupt manager capable of managing multiple MSI bindings between MSI resources to an interrupt facility, and interfaced with an underlying hardware platform of a computer through platform-specific encapsulation program code.

Message signaled interrupt management for a computer input/output fabric incorporating platform independent interrupt manager

A soft lock mechanism controls access by multiple processes to a shared resource to make simultaneous access an unlikely event, while not necessarily preventing simultaneous access. Preferably, the soft lock contains a next_free_time field, specifying when the soft lock will next be available, and a lock_duration, specifying a sufficiently long interval for most accesses to the resource to complete. The lock is obtained by comparing the current time to next_free_time. If the current time is later than next_free_time, then the lock is obtained immediately, and next_free_time is updated to the current time plus lock_duration. If the current time is before next_free_time, then next_free_time is incremented by lock_duration, and the requesting process waits until the old next_free_time to obtain the lock. No action is required to release the lock.

Method and apparatus for reducing contention for computer system resources using soft locks

A logically-partitioned computer, program product and method utilize a flexible and adaptable communication interface between a partition and a partition manager, which permits optimal handling of partition management operations such as state change operations and the like over a wide variety of circumstances. In particular, a partition is permitted to indicate, in connection with a request to perform a partition management operation, whether an asynchronous notification should be generated or suppressed in association with the performance of the partition management operation by a partition manager. As a result, asynchronous notifications are selectively generated in association with the performance of partition management operations based upon indications in the requests made by partitions for such operations.

Selective generation of an asynchronous notification for a partition management operation in a logically-partitioned computer

Disclosed is an apparatus, method, and program product that provides atomic, multi-word load support without incurring additional memory utilization. A double-word is atomically loaded without the use of one or more additional fields and without a lock. An invalidity marker is used in connection with a cache miss time to ascertain whether a loaded double-word has been stored and loaded atomically, and is thus, valid.

Mechanism that provides efficient multi-word load atomicity

A task synchronization mechanism operates on a global lock that is shared between processors an on local locks that are not shared between processors. The local locks are processor-specific locks. Each processor-specific lock is dedicated to a particular processor in the system. When shared access to a resource is required, a processor updates its processor-specific lock to indicate the processor is sharing the resource. Because each processor-specific lock is dedicated to a particular processor, this eliminates a significant portion of the memory bus traffic associated with all processors reading and updating the same lock. When exclusive access to a resource is required, the requesting processor waits until the count of all processor-specific locks indicate that none of these processors have a lock on the resource. Once no processor has a lock on the resource, exclusive access to the resource may be granted.

Task synchronization mechanism and method

An apparatus, program product and method of handling tasks that are sleeping and waiting for the completion of I/O operations of other tasks comprises determining a second task which is to await the completion of the I/O operations of a first task, and putting the second task to sleep. A timer is created and associated with the second task. The timer expires when a predetermined wait interval is exceeded. When the timer expires, the sleeping second task is awoken so that a sleeping task is generally prevented from waiting indefinitely for the I/O operations of another task.

Computer system, program product and method for tracking asynchronous I/O with timeout support

A journal mechanism for a database allows simultaneous deposits on multiple journal arms. According to a first embodiment, a journaling system maintains the time-order of interdependent deposits on the journal, but does not necessarily maintain the time-order of deposits that are independent of each other, thereby providing multiple simultaneous deposit points on the journal. The first embodiment provides excellent scaling of journal functions as processors are added to a database computer system. According to a second embodiment, a journaling system maintains the time-order of deposits on the journal, but allows a group of deposits known as a &ldquo;bundle&rdquo; to span multiple journal arms, thereby providing multiple simultaneous deposit points on the journal. The second embodiment provides good scaling while providing compatibility with known database systems. The present invention thus relieves contention for the journal that exists as the number of processors increases in a database system.

Database journal mechanism and method that supports multiple simultaneous deposits

A method and system of journal bundling that provides improved performance. In the preferred embodiment, a journal controller starts a timer to expire at a predetermined maximum time-to-wait. The journal controller then accumulates journal records in a bundle and transmits the bundle to the journal. The journal controller determines the number-of-journal-records accumulated in the bundle based on an adjustable preferred-bundle-size, which it calculates from an average-bundle-size over a history interval. If the timer expires, the journal controller writes the bundle to the journal even if the preferred-bundle-size has not been reached. By basing the preferred-bundle-size on an average-bundle-size over a history interval, the journal controller prevents rapid changes in the journal traffic-rate, which increases journal performance.

Adaptive time-based journal bundling

According to the present invention, pool allocation and process assignment mechanisms create process nodal affinity in a NUMA multiprocessor system for enhanced performance. The multiprocessor system includes multiple interconnected multiprocessing nodes that each contain one or more processors and a local main memory, the system main storage being distributed among the local main memories of the multiprocessing nodes in a NUMA architecture. A pool reservation mechanism reserves pools of memory space within the logical main storage, and the pool allocation mechanism allocates those pools to real pages in the local main-memory of multiprocessing nodes. Processes to be created on the multiprocessor are given an attribute that indicates an associated pool. Upon creation, the process assignment mechanism will only assign a process to a multiprocessing node that has been allocated the pool indicated by the process' attribute. This process nodal affinity increases accesses by the assigned process to local main storage of that node, thereby enhancing system performance.

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Rochester, MN, United States of America

Timothy Joseph Torzewski