Abstract: Embodiments of the invention provide methods and apparatus for increasing the number of page attributes specified by a page table while minimizing an increase in size of the page table. According to embodiments of the invention, attribute index bits may be included within a page table and may be used to determine page attributes stored within an attribute index. Additionally, embodiments of the invention provide a plurality of new page attributes.

Abstract: A design structure is provided for a slotted ring network, in which a node may transmit a non-renewable slot reservation with any unreserved slot. The reservation restricts other nodes from transmitting a new packet in the slot. When the slot returns around the ring to the reserving node, the slot will be available. Preferably, reservation is made responsive to a starvation condition in the reserving node, which may be detected in any of various ways. In an optional enhancement, a reservation identifies the reserving node, and another node on the ring is free to transmit a new packet in the reserved slot if the new packet will reach its destination at or before the reserving node, and thus will not interfere with the reservation.

Abstract: A memory management mechanism requires data structures to be explicitly deallocated in the programming code, but deallocation does not immediately make the memory available for reuse. Before a deallocated memory region can be reused, memory is scanned for pointers to the deallocated region, and any such pointer is set to null. The deallocated memory is then available for reuse. Preferably, deallocated memory regions are accumulated, and an asynchronous memory cleaning process periodically scans memory to nullify the pointers. In order to prevent previously scanned memory becoming contaminated with a dangling pointer before the scan is finished, any write to a pointer is checked to verify that the applicable target address has not been deallocated.

Abstract: In a slotted ring network, a node may transmit a non-renewable slot reservation with any unreserved slot. The reservation restricts other nodes from transmitting a new packet in the slot. When the slot returns around the ring to the reserving node, the slot will be available. Preferably, reservation is made responsive to a starvation condition in the reserving node, which may be detected in any of various ways. In an optional enhancement, a reservation identifies the reserving node, and another node on the ring is free to transmit a new packet in the reserved slot if the new packet will reach its destination at or before the reserving node, and thus will not interfere with the reservation.

Abstract: Page size prediction is used to predict a page size for a page of memory being accessed by a memory access instruction such that the predicted page size can be used to access an address translation data structure. By doing so, an address translation data structure may support multiple page sizes in an efficient manner and with little additional circuitry disposed in the critical path for address translation, thereby increasing performance.

Abstract: An apparatus and method utilize compressed cache lines that incorporate embedded prefetch history data associated with such cache lines. In particular, by compressing at least a portion of the data in a cache line, additional space may be freed up in the cache line to embed prefetch history data associated with the data in the cache line. By doing so, long-lived prefetch history data may essentially be embedded in a cache line and retrieved in association with that cache line to initiate the prefetching of additional data that is likely to be accessed based upon historical data generated for that cache line, and often with no little or no additional storage overhead.