Abstract: Memory Access Coloring provides architecture support that allows software to classify memory accesses into different congruence classes by specifying a color for each memory access operation. The color information is received and recorded by the underlying system with appropriate granularity. This allows hardware to monitor color-based cache monitoring information and provide such feedback to the software to enable various runtime optimizations. It also enables enforcement of different memory consistency models for memory regions with different colors at the same time.

Abstract: A virtual tape server (VTS) and a method for managing shared first level storage, such as a disk cache, among multiple virtual tape servers are provided. Such a system and method manage first level storage to accommodate two or more host processing systems by maintaining adequate free space in the cache for each host and by preventing one host, such as a mainframe, from taking over free space from another host, such as a Linux system.

Abstract: A method for performing refresh operations is disclosed. In response to a completion of a memory operation, a determination is made whether or not a refresh backlog count is greater than a first predetermined value. In a determination that the refresh backlog count is greater than the first predetermined value, a refresh operation is performed as soon as possible. In a determination that the refresh backlog count is not greater than the first predetermined value, a refresh operation is performed after a delay of an idle count value.

Abstract: A customizable cache discard policy is provided which reduces adverse consequences of conventional discard policies. In a data processing system, a cache controller invokes a cache data discard policy as the cache approaches its capacity. Using one possible policy, data having the shortest retrieval (fetch) time is discarded before data having longer retrieval times. In an alternative policy, data may be discarded based upon its source. Weightings may be applied based upon the distance from each source to the cache, may be based upon priorities assigned to each source, or may be based upon the type of each source.

Abstract: A method, system and processing device for retiring data entries held within a store queue (STQ). The STQ of a processor cache is modified to receive and process several types of data entries including: non-synchronized (non-sync), thread of execution synchronized (thread-sync), and all thread of execution synchronized (all-thread-sync). The task of storing data entries, from the STQ out to memory or an input/output device, is modified to increase the effectiveness of the cache. The modified STQ allows non-sync, thread-sync, and all-thread-sync instructions to coexist in the STQ regardless of the thread of execution. Stored data entries, or stores are deterministically selected for retirement, according to the data entry type.

Abstract: The present invention relates to a method for processing data entities by a data processing system, wherein: a first and a second set of data entities are stored in a main memory and associated with a respective first and second set of points of a domain; the first set of data entities is loaded into a local storage; one or more first calculations are performed using the first set of data entities to generate first calculated data; the second set of data entities is determined according to at least some of the first calculated data; the determined second set of data entities is loaded into the local storage; and one or more second calculations are performed using the second set of data entities resulting in second calculated data.

Abstract: A method for preserving memory affinity in a computer system is disclosed. The method reduces and sometimes eliminates memory affinity loss due to process migration by restoring the proper memory affinity through dynamic page migration. The memory affinity access patterns of individual pages are tracked continuously. If a particular page is found almost always to be accessed from a particular remote access affinity domain for a certain number of times, and without any intervening requests from other access affinity domain, the page will migrate to that particular remote affinity domain so that the subsequent memory access becomes local memory access. As a result, the proper pages are migrated to increase memory affinity.

Abstract: In a computer system supporting memory compression and wherein data is stored on a disk in a different compressed format, and wherein an IOA (input/output adaptor)/IOP (input/output processor) selectively reads from and writes to a main memory through a direct memory access (DMA) operation, a method for transmitting compressed data from the IOA/IOP to the main memory includes reserving a set of free memory sectors to contain the data in said main memory, sending to the IOA/IOP addresses of said memory sectors, copying the data from the IOA/IOP to said memory sectors using said DMA operation, constructing at the IOA/IOP compressed memory directory information defining how and where the data is stored in memory, sending the memory directory information to a memory controller, and storing the memory directory information in the compressed memory directory structure.

Abstract: An information handling system includes a processor with an array power management controller. The array power management controller gates off a memory array, such as a cache, to conserve power whenever a group of instructions in a branch instruction queue together as a group exhibits a confidence in the accuracy of branch predictions of branch instructions therein that is less than a first predetermined threshold confidence threshold. In one embodiment of the information handling system, the array power management controller speculatively inhibits the gating off of the memory array when confidence in the accuracy of a branch prediction for a particular currently issued branch instruction exhibits less than a second predetermined threshold confidence threshold. In this manner, the array power management controller again allows access to the memory array in the event a branch redirect is likely.

Abstract: Method, system and computer program product are provided for detecting and correcting dropped writes in a storage system. Data and a checksum are written to a storage device, such as a RAID array. The state of the data is classified as being in a “new data, unconfirmed” state. The state of written data is periodically checked, such as with a timer. If the data is in the “new data, unconfirmed” state, it is checked for a dropped write. If a dropped write has occurred, the state of the data is changed to a “single dropped write confirmed” state and the dropped write error is preferably corrected. If no dropped write is detected, the state is changed to a “confirmed good” state. If the data was updated through a read-modified-write prior to being checked for a dropped write event, its state is changed to an “unquantifiable” state.

Abstract: Management of a UNIX-style storage pools is enhanced by specially managing one or more memory management inodes associated with pinned and allocated pages of data storage by providing indirect access to the pinned and allocated pages by one or more user processes via a handle, while preventing direct access of the pinned and allocated pages by the user processes without use of the handles; scanning periodically hardware status bits in the inodes to determine which of the pinned and allocated pages have been recently accessed within a pre-determined period of time; requesting via a callback communication to each user process to determine which of the least-recently accessed pinned and allocated pages can be either deallocated or defragmented and compacted; and responsive to receiving one or more page indicators of pages unpinned by the user processes, compacting or deallocating one or more pages corresponding to the page indicators.

Abstract: A method, data processing system and computer program product enables efficient transfer of a virtual machine from a first data processing system (DPS) to a second DPS using a combination of Transmission Control Protocol (TCP) and Uniform Data Protocol (UDP). A virtual machine migration (VMM) utility identifies all memory pages of the first virtual machine. The VMM utility notifies the second DPS via TCP of the scheduled transfer of the virtual machine. The VMM utility copies and transfers the memory pages of the virtual machine to the second DPS via UDP. When all expected components of the virtual machine are not received by the second DPS and/or memory data is modified within the memory pages during the migration, the VMM utility combines the missing data and the modified data and transfers the final components of the virtual machine using TCP. Execution of the virtual machine resumes on the second DPS.

Abstract: A memory system and data processing system for controlling memory refresh operations in dynamic random access memories. The memory controller comprises logic that: tracks a time remaining before a scheduled time for performing a high priority, high latency operation a first memory rank of the memory system; responsive to the time remaining reaching a pre-established early notification time before the schedule time for performing the high priority, high latency operation, biases the re-order queue containing memory access operations targeting the plurality of ranks to prioritize scheduling of any first memory access operations that target the first memory rank. The logic further: schedules the first memory access operations to the first memory rank for early completion relative to other memory access operations in the re-order queue that target other memory ranks; and performs the high priority, high latency operation at the first memory rank at the scheduled time.

Abstract: A method, system, and computer program product provide a shared virtual memory space via a cluster-aware virtual input/output (I/O) server (VIOS). The VIOS receives a paging file request from a first LPAR and thin-provisions a logical unit (LU) within the virtual memory space as a shared paging file of the same storage amount as the minimum required capacity. The VIOS also autonomously maintains a logical redundancy LU (redundant LU) as a real-time copy of the provisioned/allocated LU, where the redundant LU is a dynamic copy of the allocated LU that is autonomously updated responsive to any changes within the allocated LU. Responsive to a second VIOS attempting to read a LU currently utilized by a first VIOS, the read request is autonomously redirected to the logical redundancy LU. The redundant LU can be utilized to facilitate migration of a client LPAR to a different computing electronic complex (CEC).

Abstract: An information handling system (IHS) includes a processor with a cache memory system. The processor includes a processor core with an L1 cache memory that couples to an L2 cache memory. The processor includes an arbitration mechanism that controls load and store requests to the L2 cache memory. The arbitration mechanism includes control logic that enables a load request to interrupt a store request that the L2 cache memory is currently servicing. When the L2 cache memory finishes servicing the interrupting load request, the L2 cache memory may return to servicing the interrupted store request at the point of interruption. The control logic determines the size requirement of each load operation or store operation. When the cache memory system performs a store operation or load operation, the memory system accesses the portion of a cache line it needs to perform the operation instead of accessing an entire cache line.