Abstract: A computer system and corresponding method for supporting a compressed main memory includes a processor, a processor cache in signal communication with the processor, a memory controller in signal communication with the processor cache, a compression translation table entry register in signal communication with the processor cache and the memory controller, a compression translation table directory in signal communication with the compression translation table entry register, and a compressed main memory in signal communication with the memory controller wherein the memory controller manages the compressed main memory by storing entries of the compression translation table directory into the processor cache from the compression translation table entry register; where the corresponding method includes receiving a real address for a processor cache miss, finding a compression translation table address for the cache miss within the processor cache, if the cache miss is a cache write miss: decompressing the memor

Abstract: A compressed memory system includes a cache, and compressed memory including fixed size storage blocks for storing both compressed data segments and fixed size storage blocks defining a virtual uncompressed cache (VUC) for storing uncompressed data segments to enable reduced data access latency. The compressed memory system implements a system and method for controlling the size of the VUC so as to optimize system performance in a manner which permits the avoidance of operating system intervention which is required in certain circumstances for correct system operation. The system solves-these problems by implementing one or more thresholds, which may be set by the operating system, but which, after being sets control the size of the VUC independently of the operating system or other system software.

Abstract: A computer system and a method for enhancing the cache prefetch behavior. A computer system including a processor, a main memory, a prefetch controller, a cache memory, a prefetch buffer, and a main memory, wherein each page in the main memory has associated with it a tag, which is used for controling the prefetching of a variable subset of lines from this page as well as lines from at least one other page. And, coupled to the processor is a prefetch controller, wherein the prefetch controller responds to the processor determining a fault (or miss) occurred to a line of data by fetching a corresponding line of data with the corresponding tag, with the corresponding tag to be stored in the prefetch buffer, and sending the corresponding line of data to the cache memory.

Abstract: A computing system and method employing a processor device for generating real addresses associated with memory locations of a real memory system for reading and writing of data thereto, the system comprising: a plurality of memory blocks in the real memory system for storing data, a physical memory storage for storing the pages of data comprising one or more real memory blocks, each real memory block partitioned into one or more sectors, each comprising contiguous bytes of physical memory; a translation table structure in the physical memory storage having entries for associating a real address with sectors of the physical memory, each translation table entry including one or more pointers for pointing to a corresponding sector in its associated real memory block, the table accessed for storing data in one or more allocated sectors for memory read and write operations initiated by the processor; and, a control device for directly manipulating entries in the translation table structure for performing page ope

Abstract: A computer system having a main memory for storing data in a compressed format and a processor cache for storing decompressed data, a method for converting the data of said main memory from compressed to uncompressed state, comprising the steps of reducing used portions of said main memory to a target value; disabling a compressor used for compressing the uncompressed data; decompressing said compressed data of said main memory; moving said decompressed data to physical addresses equal to real addresses; and releasing the memory occupied by a compressed memory director and data structures used in steps a. to d.

Abstract: A method (and system) of storing information, includes storing main memory compressed information onto a memory compressed disk, where pages are stored and retrieved individually, without decompressing the main memory compressed information.

Abstract: A method and structure is disclosed for constraining cache line replacement that processes a cache miss in a computer system. The invention contains a K-way set associative cache that selects lines in the cache for replacement. The invention constrains the selecting process so that only a predetermined subset of each set of cache lines is selected for replacement. The subset has at least a single cache line and the set size is at least two cache lines. The invention may further select between at least two cache lines based upon which of the cache lines was accessed least recently. A selective enablement of the constraining process is based on a free space memory condition of a memory associated with the cache memory. The invention may further constrain cache line replacement based upon whether the cache miss is from a non-local node in a nonuniform-memory-access system. The invention may also process cache writes so that a predetermined subset of each set is known to be in an unmodified state.

Abstract: A computing system and method employing a processor device for generating real addresses associated with memory locations of a real memory system for reading and writing of data thereto, the system comprising: a plurality of memory blocks in the real memory system for storing data, a physical memory storage for storing the pages of data comprising one or more real memory blocks, each real memory block partitioned into one or more sectors, each comprising contiguous bytes of physical memory; a translation table structure in the physical memory storage having entries for associating a real address with sectors of the physical memory, each translation table entry including one or more pointers for pointing to a corresponding sector in its associated real memory block, the table accessed for storing data in one or more allocated sectors for memory read and write operations initiated by the processor; and, a control device for directly manipulating entries in the translation table structure for performing page ope

Abstract: In a computer system in which a plurality of hosts is connected through an interconnection network, an apparatus coupled to the interconnection network for allowing the plurality of hosts to share a collection of memory sectors, the memory sectors storing compressed data, is provided. The apparatus includes a network adapter for coupling the apparatus to the interconnection network; a memory for storing the collection of memory sectors; and control logic for managing the memory, the control logic including a memory compressor/decompressor. The memory further includes a directory for translating real addresses of at least one host to an address in the apparatus. A method for managing a number of memory sectors used by each host and a method for translating a real address specified by at least one host into a real address of the apparatus is also provided.

Abstract: A computer system and corresponding method for supporting a compressed main memory includes a processor, a processor cache in signal communication with the processor, a memory controller in signal communication with the processor cache, a compression translation table entry register in signal communication with the processor cache and the memory controller, a compression translation table directory in signal communication with the compression translation table entry register, and a compressed main memory in signal communication with the memory controller wherein the memory controller manages the compressed main memory by storing entries of the compression translation table directory into the processor cache from the compression translation table entry register; where the corresponding method includes receiving a real address for a processor cache miss, finding a compression translation table address for the cache miss within the processor cache, if the cache miss is a cache write miss: decompressing the memor

Abstract: In a computer system having a processor, a memory system including multiple levels of caches L1, L2, . . . , Ln−1 and including main memory Ln, and in which the cache Li−1 includes lines of size s and the cache Li includes lines of size t with t>s, a dual line size cache directory mechanism, in which the contents of a cache Li−1 may be accessed at line size granularity s (in which case it is determined whether a line corresponding to a given memory address is stored in Li−1, and if so its location and status), and in which the contents of Li−1 may also be accessed at line size granularity t (in which case it is determined whether any of the t/s lines of size s residing in the larger line of size t corresponding to a given memory address are stored in Li−1, and if so their locations and status) without multiple sequential accesses to a cache Li−1 directory structure.

Abstract: A computing system includes a storage server having a memory organization that includes a compressed memory device for storing sectors, each sector having a sector data portion and associated header and trailers, either attached by the hosts or by components of the computing system. The compressed memory device comprises a memory directory and a plurality of fixed-size blocks. The system implements a methodology for detaching headers and trailers from sectors before storing the sectors in the memory, and storing the headers and trailers in the memory disk cache, separate from the sector data portion; and, reattaching headers and trailers to sector data portions when the sectors are sent from the memory to a host or to a mass storage device. The header and trailer data are managed through the same memory directory used to manage the compressed main memory.

Abstract: A method for predicting a subsequent resource utilization in a computer system having a plurality of devices includes the step of monitoring, over a period of time, a contemporaneous resource utilization and a number of active devices to obtain monitored values of the contemporaneous resource utilization and the number of active devices. The subsequent resource utilization is predicted, based upon the monitored values of the contemporaneous resource utilization and the number of active devices. Additionally, methods are described herein for identifying resource saturation and predicting the effects of adding a new device in a computer system.

Abstract: Disclosed is a method of managing memory to prevent an operating system from writing into user memory space, the method comprising providing a translation look-aside buffer (TLB) for storing TLB entries, each said TLB entry comprising a virtual address of a page in system memory space, a real address of said page, a flag entry for storing a value F indicating whether said page is a user page in said user memory space, providing a space recovery mode register comprising a mode entry for storing a value E indicating whether the system is in a normal mode or in a space recovery mode, said value of E set to said space recovery mode when available free user space fall below a predetermined threshold value, and for each said TLB entry, designating said page in system memory space as read-only when F=0 and E=0. An alternative embodiment is also disclosed wherein no modifications to memory structures are required.

Abstract: A computing system includes a storage server having a memory organization that includes a compressed memory device for storing sectors, each sector having a sector data portion and associated header and trailers, either attached by the hosts or by components of the computing system. The compressed memory device comprises a memory directory and a plurality of fixed-size blocks. The system implements a methodology for detaching headers and trailers from sectors before storing the sectors in the memory, and storing the headers and trailers in the memory disk cache, separate from the sector data portion; and, reattaching headers and trailers to sector data portions when the sectors are sent from the memory to a host or to a mass storage device. The header and trailer data are managed through the same memory directory used to manage the compressed main memory.

Abstract: In a computer system, a system and methodology for dynamically allocating available physical memory to addressable memory space on an as needed basis, and to recover unused physical memory space when it is no longer needed. Physical memory is assigned to addressable memory space when that memory space is first written. When the system software determines it has no further need of a memory space, the physical memory is recovered and made available for reuse.

Abstract: A system including a CPU, memory, and compression controller hardware, and implementing a first directory structure included in a first memory wherein CPU generated real memory addresses are translated into one or more physical memory locations using the first directory structure, further includes a second directory cache structure having entries corresponding to directory entries included in the first directory structure. In a first embodiment, the second directory cache structure is implemented as part of compression controller hardware. In a second embodiment, a common directory and cache memory structure is provided for storing a subset of directory entries in the directory structure together with a subset of the memory contents.

Abstract: System and method for reducing data access latency for cache miss operations in a computer system implementing main memory compression in which the unit of compression is a memory segment. The method includes steps of providing common memory area in main memory for storing compressed and uncompressed data segments; accessing directory structure formed in the main memory having entries for locating both uncompressed data segments and compressed data segments for cache miss operations, each directory entry including index for locating data segments in the main memory and further indicating status of the data segment; and, checking a status indication of a data segment to be accessed for a cache miss operation, and processing either a compressed or uncompressed data segment from the common memory area according to the status.

Abstract: A system for accessing contents of the directory structure in a computing system having a CPU and implementing indirectly addressable main memory via a first directory structure included in the memory. In this system, CPU generated real memory addresses are translated to one or more physical memory locations using the directory structure. A second directory structure is provided in main memory that includes one or more entries with each entry formatted to provide addressability to a predetermined number of entries in the first directory structure. The second directory structure alternately may access all contents of main memory, and is adaptable as main memory capacity varies. The second directory structure may alternately be implemented as a hardware device which computes the addresses for accessing data in main memory.

Abstract: A system for accessing contents of the directory structure in a computing system having a CPU and implementing indirectly addressable main memory via a first directory structure included in the memory. In this system, CPU generated real memory addresses are translated to one or more physical memory locations using the directory structure. A second directory structure is provided in main memory that includes one or more entries with each entry formatted to provide addressability to a predetermined number of entries in the first directory structure. The second directory structure alternately may access all contents of main memory, and is adaptable as main memory capacity varies. The second directory structure may alternately be implemented as a hardware device which computes the addresses for accessing data in main memory.