Abstract: Methods, systems and software for inserting prefetches into software applications or programs are described. A baseline program is analyzed to identify target instructions for which prefetching may be beneficial using various pattern analyses. Optionally, a cost/benefit analysis can be performed to determine if it is worthwhile to insert prefetches for the target instructions.

Abstract: One or more of the present techniques provide a compute engine buffer configured to maneuver data and increase the efficiency of a compute engine. One such compute engine buffer is connected to a compute engine which performs operations on operands retrieved from the buffer, and stores results of the operations to the buffer. Such a compute engine buffer includes a compute buffer having storage units which may be electrically connected or isolated, based on the size of the operands to be stored and the configuration of the compute engine. The compute engine buffer further includes a data buffer, which may be a simple buffer. Operands may be copied to the data buffer before being copied to the compute buffer, which may save additional clock cycles for the compute engine, further increasing the compute engine efficiency.

Abstract: The invention may be embodied in a cache memory volume windows data storage system to enable cache memory rebuilds in response to power-on-reset (POR) events. To handle POR events occurring while a flush from the cache memory to the permanent memory is taking place, the storage controller maintains duplicate copy of a volume window bitmap and a volume mark register while a portion of the cache memory unavailable due to the flush event. The second copy of the volume bit map and volume mark register concatenation are used to account for the case where a POR event occurs while the flush is in process. The firmware uses the peer drives and the applicable cache rebuild protocol (e.g., RAID) to rebuild the data for all volume windows that contain data that may have become corrupted due to a POR event occurring during cache memory flush events are in progress.

Abstract: A multiprocessor system includes nodes. Each node includes a data path that includes a core, a TLB, and a first level cache implementing disambiguation. The system also includes at least one second level cache and a main memory. For thread memory access requests, the core uses an address associated with an instruction format of the core. The first level cache uses an address format related to the size of the main memory plus an offset corresponding to hardware thread meta data. The second level cache uses a physical main memory address plus software thread meta data to store the memory access request. The second level cache accesses the main memory using the physical address with neither the offset nor the thread meta data after resolving speculation. In short, this system includes mapping of a virtual address to a different physical addresses for value disambiguation for different threads.

Abstract: Technologies are generally described herein for determining a profitability of direct fetching in a multicore processor. The multicore processor may include a first and a second tile. The first tile may include a first core and a first cache. The second tile may include a second core, a second cache, and a fetch location pointer register (FLPR). The multicore processor may migrate a thread executing on the first core to the second core. The multicore processor may store a location of the first cache in the FLPR. The multicore processor may execute the thread on the second core. The multicore processor may identify a cache miss for a block in the second cache. The multicore processor may determine whether a profitability of direct fetching of the block indicates direct fetching or directory-based fetching. The multicore processor may perform direct fetching or directory-based fetching based on the determination.

Abstract: Information is maintained on strides configured in a second cache and occupancy counts for the strides indicating an extent to which the strides are populated with valid tracks and invalid tracks. A determination is made of tracks to demote from a first cache. A first stride is formed including the determined tracks to demote. The tracks from the first stride are to a second stride in the second cache having an occupancy count indicating the stride is empty. A determination is made of a target stride in the second cache based on the occupancy counts of the strides in the second cache. A determination is made of at least two source strides in the second cache having valid tracks based on the occupancy counts of the strides in the second cache. The target stride is populated with the valid tracks from the source strides.

Abstract: Information on strides configured in the second cache includes information indicating a number of valid tracks in the strides, wherein a stride has at least one of valid tracks and free tracks not including valid data. A determination is made of tracks to demote from the first cache. A first stride is formed including the determined tracks to demote. The tracks from the first stride are added to a second stride in the second cache that has no valid tracks. A target stride in the second cache is selected based on a stride most recently used to consolidate strides from at least two strides into one stride. Data from the valid tracks is copied from at least two source strides in the second cache to the target stride.

Abstract: Provided are a computer program product, system, and method for handling high priority requests in a sequential access storage device. Received modified tracks for write requests are cached in a non-volatile storage device integrated with the sequential access storage device. A destage request is added to a request queue for a received write request having modified tracks for the sequential access storage medium cached in the non-volatile storage device. A read request indicting a priority is received. A determination is made of a priority of the read request as having a first priority or a second priority. The read request is added to the request queue in response to determining that the determined priority is the first priority. The read request is processed at a higher priority than the read and destage requests in the request queue in response to determining that the determined priority is the second priority.

Abstract: Information on strides configured in the second cache includes information indicating a number of valid tracks in the strides, wherein a stride has at least one of valid tracks and free tracks not including valid data. A determination is made of tracks to demote from the first cache. A first stride is formed including the determined tracks to demote. The tracks from the first stride are added to a second stride in the second cache that has no valid tracks. A target stride in the second cache is selected based on a stride most recently used to consolidate strides from at least two strides into one stride. Data from the valid tracks is copied from at least two source strides in the second cache to the target stride.

Abstract: Information is maintained on strides configured in a second cache and occupancy counts for the strides indicating an extent to which the strides are populated with valid tracks and invalid tracks. A determination is made of tracks to demote from a first cache. A first stride is formed including the determined tracks to demote. The tracks from the first stride are to a second stride in the second cache having an occupancy count indicating the stride is empty. A determination is made of a target stride in the second cache based on the occupancy counts of the strides in the second cache. A determination is made of at least two source strides in the second cache having valid tracks based on the occupancy counts of the strides in the second cache. The target stride is populated with the valid tracks from the source strides.

Abstract: Technologies are generally described for methods, systems, and devices effective to implement one-cacheable multi-core architectures. In one example, a multi-core processor that includes a first and second tile may be configured to implement a one-cacheable architecture. The second tile may be configured to generate a request for a data block. The first tile may be configured to receive the request for the data block, and determine that the requested data block is part of a group of data blocks identified as one-cacheable. The first tile may further determine that the requested data block is stored in a first cache in the first tile. The first tile may send the data block from the first cache in the first tile to the second tile, and invalidate the data blocks of the group of data blocks in the first cache in the first tile.

Abstract: A memory subsystem includes a volatile memory, a nonvolatile memory, and a controller including logic to interface the volatile memory to an external system. The volatile memory is addressable for reading and writing by the external system. The memory subsystem includes a power controller with logic to detect when power from the external system to at least one of the volatile and nonvolatile memories and to the controller fails. When external system power fails, backup power is provided to at least one of the volatile and nonvolatile memories and to the controller for long enough to enable the controller to back up data from the volatile memory to the nonvolatile memory.

Abstract: Provided are a computer program product, system, and method for managing track discard requests to include in discard track messages. A backup copy of a track in a cache is maintained in the cache backup device. A track discard request is generated to discard tracks in the cache backup device removed from the cache. Track discard requests are queued in a discard track queue. In response to detecting that a predetermined number of track discard requests are queued in the discard track queue while processing in a discard multi-track mode, one discard multiple tracks message is sent indicating the tracks indicated in the queued predetermined number of track discard requests to the cache backup device instructing the cache backup device to discard the tracks indicated in the discard multiple tracks message. In response to determining a predetermined number of periods of inactivity while processing in the discard multi-track mode, processing the track discard requests is switched to a discard single track mode.

Abstract: Private or shared read-only memory regions. One embodiment may be practiced in a computing environment including a plurality of agents. A method includes acts for declaring one or more memory regions private to a particular agent or shared read only amongst agents by having software utilize processor level instructions to specify to hardware the private or shared read only memory address regions. The method includes an agent executing a processor level instruction to specify one or more memory regions as private to the agent or shared read-only amongst a plurality of agents. As a result of an agent executing a processor level instruction to specify one or more memory regions as private to the agent or shared read-only amongst a plurality of agents, a hardware component monitoring the one or more memory regions for conflicting accesses or prevents conflicting accesses on the one or more memory regions.

Abstract: System and techniques for rebuilding a redundant secondary storage cache including a first storage device and a second storage device are described. A metadata entry indicative of a validity of a portion of information stored by a first storage cache device and associated with a region of a primary storage device is received. When the validity of the portion of information associated with the region of the primary storage device is established, a region lock is requested on the region of the primary storage device associated with the portion of information stored by the first storage cache device. Then, the portion of information and the corresponding metadata entry associated with the region of the primary storage device is copied from the first cache storage device to a second storage cache device to rebuild the second storage cache device.

Abstract: Data values are cached by dynamically determining the dependencies of computation nodes on input parameters and on other results of computation nodes. Cache data structures are maintained for computation nodes. When a node accesses a parameter, the parameter and its current value are added to the node's cache data structure. The cache data structure stores the result value of the computation node. When one computation node calls another node, the parameters and parameter values accessed by the second computation node may be added to the first and second computation nodes' cache data structures. When a computation node is called with parameter values, the cache data structure of the computation node is searched for a cached result value corresponding to at least a portion of the parameter values. If a cached result value is not found, the computation node is executed to determine and optionally cache the result value.

Abstract: Protecting computers against cache poisoning, including a cache-entity table configured to maintain a plurality of associations between a plurality of data caches and a plurality of entities, where each of the caches is associated with a different one of the entities, and a cache manager configured to receive data that is associated with any of the entities and store the received data in any of the caches that the cache-entity table indicates is associated with the entity, and receive a data request that is associated with any of the entities and retrieve the requested data from any of the caches that the cache-entity table indicates is associated with the requesting entity, where any of the cache-entity table and cache manager are implemented in either of computer hardware and computer software embodied in a computer-readable medium.

Abstract: A data storage system includes two tiers of caching memory. Cached data is organized into cache windows, and the cache windows are organized into a plurality of priority queues. Cache windows are moved between priority queues on the basis of a threshold data access frequency; only when both a cache window is flagged for promotion and a cache window is flagged for demotion will a swap occur.

Abstract: Provided are a computer program product, system, and method for managing unmodified tracks maintained in both a first cache and a second cache. The first cache has unmodified tracks in the storage subject to Input/Output (I/O) requests. Unmodified tracks are demoted from the first cache to a second cache. An inclusive list indicates unmodified tracks maintained in both the first cache and a second cache. An exclusive list indicates unmodified tracks maintained in the second cache but not the first cache. The inclusive list and the exclusive list are used to determine whether to promote to the second cache an unmodified track demoted from the first cache.

Abstract: A method and central processing unit supporting atomic access of shared data by a sequence of memory access operations. A processor status flag is reset. A processor executes, subsequent to the setting of the processor status flag, a sequence of program instructions with instructions accessing a subset of shared data contained within its local cache. During execution of the sequence of program instructions and in response to a modification by another processor of the subset of shared data, the processor status flag is set. Subsequent to the executing the sequence of program instructions and based upon the state of the processor status flag, either a first program processing or a second program processing is executed. In some examples the first program processing includes storing results data into the local cache and the second program processing includes discarding the results data.

Abstract: Various method and system embodiments for facilitating catalog sharing in multiprocessor systems use multiple ECS cache structures to which catalogs are assigned based on an attribute such as SMS storage class or a high level qualifier (HLQ) (e.g. an N-to-1 mapping) or each individual catalog (e.g. a 1-to-1 mapping). When maintenance is performed on an ECS shared catalog, the multiple ECS cache structure requires only those catalogs associated with a particular ECS cache structure be disconnected. Any catalogs in the structure that are not involved in or affected by the maintenance may be temporarily or permanently moved to a different ECS cache structure. As a result, VVDS sharing is only required for those catalogs on which maintenance is being performed or that remain associated with that ECS cache structure during maintenance. This reduces I/O activity to the DASD, and results in a significant overall performance improvement.

Abstract: Network cache systems are used to improve network performance and reduce network traffic. An improved network cache system that uses a centralized shared cache system is disclosed. Each cache device that shares the centralized shared cache system maintains its own catalog, database or metadata index of the content stored on the centralized shared cache system. When one of the cache devices that shares the centralized shared cache system stores a new content resource to the centralized shared cache system, that cache device transmits a broadcast message to all of the peer cache devices. The other cache devices that receive the broadcast message will then update their own local catalog, database or metadata index of the centralized share cache system with the information about the new content resource.

Abstract: Provided are a prioritized dual caching method and apparatus. The dual caching apparatus includes a content cache unit configured to store a content cache separated into a first (premium) cache and a second (general) cache, a pointer storage unit configured to store a pointer for variably separating the first and second caches, a threshold value storage unit configured to store a first threshold value and a second threshold value that is less than the first threshold value, and a cache policy execution unit configured to receive a request for content, manage a request count value for the content, and execute a cache policy based on results of comparing the request count value to the first threshold value and the second threshold value and whether there is requested content in the content cache.

Abstract: Provided a computer program product, system, and method for cache management of tracks in a first cache and a second cache for a storage. The first cache maintains modified and unmodified tracks in the storage subject to Input/Output (I/O) requests. Modified and unmodified tracks are demoted from the first cache. The modified and the unmodified tracks demoted from the first cache are promoted to the second cache. The unmodified tracks demoted from the second cache are discarded. The modified tracks in the second cache that are at proximate physical locations on the storage device are grouped and the grouped modified tracks are destaged from the second cache to the storage device.

Abstract: A cache memory system using temporal locality information and a data storage method are provided. The cache memory system including: a main cache which stores data accessed by a central processing unit; an extended cache which stores the data if the data is evicted from the main cache; and a separation cache which stores the data of the extended cache when the data of the extended cache is evicted from the extended cache and temporal locality information corresponding to the data of the extended cache satisfies a predetermined condition.

Abstract: For data processing in a computing storage environment by a processor device, the computing storage environment incorporating at least high-speed and lower-speed caches, and managed tiered levels of storage, a Solid State Device (SSD) tier is variably shared between the lower-speed cache and the managed tiered levels of storage such that the managed tiered levels of storage are operational on large data segments, and the lower-speed cache is allocated with the large data segments, yet operates with data segments of a smaller size than the large data segments and within the large data segments.

Abstract: An information processing apparatus including a plurality of mutually connected system boards, wherein each of the system boards includes: a plurality of processors; and a plurality of memories each of which stores data and directory information corresponding to the data, and corresponds to any one of the processors, and wherein each of the plurality of processors, upon receiving a read request for data stored in a memory corresponding to the own processor from another processor, performs an exclusive logical sum operation on identification information included in the read request and identifying the another processor and a check bit included in the directory information and identifying a processor which holds target data of the read request, increments a count value included in the directory information and indicating the number of processors which hold the target data, and sets presence information included in the directory information and indicating a system board which includes the another processor.

Abstract: For data processing in a computing storage environment by a processor device, the computing storage environment incorporating at least high-speed and lower-speed caches, and tiered levels of storage, and at a time in which at least one data segment is to be migrated from one level to another level of the tiered levels of storage, a data migration mechanism is initiated by copying data resident in the lower-speed cache corresponding to the at least one data segment to be migrated to a target on the another level, and reading remaining data, not previously copied from the lower-speed cache, from a source on the one level, and writing the remaining data to the target.

Abstract: For data processing in a computing storage environment by a processor device, the computing storage environment incorporating at least high-speed and lower-speed caches, and managed tiered levels of storage, groups of data segments are migrated between the tiered levels of storage such that uniformly hot ones of the groups of data segments are migrated to use a Solid State Drive (SSD) portion of the tiered levels of storage, clumped hot ones of the groups of data segments are migrated to use the SSD portion while using the lower-speed cache for a remaining portion of the clumped hot ones, and sparsely hot ones of the groups of data segments are migrated to use the lower-speed cache while using a lower one of the tiered levels of storage for a remaining portion of the sparsely hot ones.

Abstract: For data processing in a computing storage environment by a processor device, the computing storage environment incorporating at least high-speed and lower-speed caches, and managed tiered levels of storage, a Solid State Device (SSD) tier is variably shared between the lower-speed cache and the managed tiered levels of storage such that the managed tiered levels of storage are operational on large data segments, and the lower-speed cache is allocated with the large data segments, yet operates with data segments of a smaller size than the large data segments and within the large data segments.

Abstract: For data processing in a computing storage environment by a processor device, the computing storage environment incorporating at least high-speed and lower-speed caches, and tiered levels of storage, groups of data segments are migrated between the tiered levels of storage such that uniformly hot ones of the groups of data segments are migrated to utilize a Solid State Drive (SSD) portion of the tiered levels of storage, while sparsely hot ones of the groups of data segments are migrated to utilize the lower-speed cache.

Abstract: Provided are a computer program product, system, and method for using an attribute of a write request to determine where to cache data in a storage system having multiple caches including non-volatile storage cache in a sequential access storage device. Received modified tracks are cached in the non-volatile storage device integrated with the sequential access storage device in response to determining to cache the modified tracks. A write request having modified tracks is received. A determination is made as to whether an attribute of the received write request satisfies a condition. The received modified tracks for the write request are cached in the non-volatile storage device in response to determining that the determined attribute does not satisfy the condition. A destage request is added to a request queue for the received write request having the determined attribute not satisfying the condition.

Abstract: In various embodiments, the present disclosure provides a system comprising a first plurality of processing cores, ones of the first plurality of processing cores coupled to a respective core interface module among a first plurality of core interface modules, the first plurality of core interface modules configured to be coupled to form in a first ring network of processing cores; a second plurality of processing cores, ones of the second plurality of processing cores coupled to a respective core interface module among a second plurality of core interface modules, the second plurality of core interface modules configured to be coupled to form a second ring network of processing cores; a first global interface module to form an interface between the first ring network and a third ring network; and a second global interface module to form an interface between the second ring network and the third ring network.

Abstract: In various embodiments, the present disclosure provides a system comprising a first plurality of processing cores, ones of the first plurality of processing cores coupled to a respective core interface module among a first plurality of core interface modules, the first plurality of core interface modules configured to be coupled to form in a first ring network of processing cores; a second plurality of processing cores, ones of the second plurality of processing cores coupled to a respective core interface module among a second plurality of core interface modules, the second plurality of core interface modules configured to be coupled to form a second ring network of processing cores; a first global interface module to form an interface between the first ring network and a third ring network; and a second global interface module to form an interface between the second ring network and the third ring network.

Abstract: Systems and techniques for continuously writing to a secondary storage cache are described. A data storage region of a secondary storage cache is divided into a first cache region and a second cache region. A data storage threshold for the first cache region is determined. Data is stored in the first cache region until the data storage threshold is met. Then, additional data is stored in the second cache region while the data stored in the first cache region is written back to a primary storage device.

Abstract: In various embodiments, the present disclosure provides a system comprising a first plurality of processing cores, ones of the first plurality of processing cores coupled to a respective core interface module among a first plurality of core interface modules, the first plurality of core interface modules configured to be coupled to form in a first ring network of processing cores; a second plurality of processing cores, ones of the second plurality of processing cores coupled to a respective core interface module among a second plurality of core interface modules, the second plurality of core interface modules configured to be coupled to form a second ring network of processing cores; a first global interface module to form an interface between the first ring network and a third ring network; and a second global interface module to form an interface between the second ring network and the third ring network.

Abstract: Subject matter disclosed herein relates to sub-block accessible cache memory.

Abstract: A processor comprising: an instruction processing pipeline, configured to receive a sequence of instructions for execution, said sequence comprising at least one instruction including a flow control instruction which terminates the sequence; a hash generator, configured to generate a hash associated with execution of the sequence of instructions; a memory configured to securely receive a reference signature corresponding to a hash of a verified corresponding sequence of instructions; verification logic configured to determine a correspondence between the hash and the reference signature; and authorization logic configured to selectively produce a signal, in dependence on a degree of correspondence of the hash with the reference signature.

Abstract: A pipelined processor comprising a cache memory system, fetching instructions for execution from a portion of said cache memory system, an instruction commencing processing before a digital signature of the cache line that contained the instruction is verified against a reference signature of the cache line, the verification being done at the point of decoding, dispatching, or committing execution of the instruction, the reference signature being stored in an encrypted form in the processor's memory, and the key for decrypting the said reference signature being stored in a secure storage location. The instruction processing proceeds when the two signatures exactly match and, where further instruction processing is suspended or processing modified on a mismatch of the two said signatures.

Abstract: A method for minimizing soft error rates within caches by configuring a cache with certain sections to correspond to bitcell topologies that are more resistant to soft errors and then using these sections to store modified data.

Abstract: Techniques are disclosed related to flushing one or more data caches. In one embodiment an apparatus includes a processing element, a first cache associated with the processing element, and a circuit configured to copy modified data from the first cache to a second cache in response to determining an activity level of the processing element. In this embodiment, the apparatus is configured to alter a power state of the first cache after the circuit copies the modified data. The first cache may be at a lower level in a memory hierarchy relative to the second cache. In one embodiment, the circuit is also configured to copy data from the second cache to a third cache or a memory after a particular time interval. In some embodiments, the circuit is configured to copy data while one or more pipeline elements of the apparatus are in a low-power state.

Abstract: A virtually tagged cache may be configured to index virtual address entries in the cache into lockable sets based on a page offset value. When a memory operation misses on the virtually tagged cache, only the one set of virtual address entries with the same page offset may be locked. Thereafter, this general lock may be released and only an address stored in the physical tag array matching the physical address and a virtual address in the virtual tag array corresponding to the matching address stored in the physical tag array may be locked to reduce the amount and duration of locked addresses. The machine may be stalled only if a particular memory address request hits and/or tries to access one or more entries in a locked set. Devices, systems, methods, and computer readable media are provided.

Abstract: An information processing apparatus comprises a plurality types of cache memories having different characteristics, decides on a type of cache memory to be used as a data cache destination based on the access characteristics of cache-target data, and caches the data in the cache memory of the decided type.

Abstract: Data caching methods and systems are provided. The data cache method loads data into an installation cache and a cache (simultaneously or serially) and returns data from the installation cache when the data has not completely loaded into the cache. The data cache system includes a processor, a memory coupled to the processor, a cache coupled to the processor and the memory and an installation cache coupled to the processor and the memory. The system is configured to load data from the memory into the installation cache and the cache (simultaneously or serially) and return data from the installation cache to the processor when the data has not completely loaded into the cache.

Abstract: A method and apparatus for replicating instances of cache nodes in a cluster is described. In one embodiment, the number of available cache nodes in the cluster is determined. Available cache nodes from the cluster are selected based on a parameter. An instance of a cache node is replicated to only one of the selected cache nodes in the cluster.

Abstract: According to one embodiment, a multicore processor system includes: a memory region, and a multicore processor that includes plural cores, a first cache, and a second cache shared between the plural cores. The memory region permits first state in which exclusive use by using the first and second cache is granted to one core, second state in which exclusive use by using the second cache is granted to one core group, and third state in which use by using neither the first cache nor the second cache is granted to all core groups. A kernel unit writes back a first cache to the second cache when a transition of the memory region from the first state to the second state is made, and writes back a second cache to the memory region when a transition of the memory region from the second state to the third state is made.

Abstract: An embodiment provides a virtual address cache memory including: a TLB virtual page memory configured to, when a rewrite to a TLB occurs, rewrite entry data; a data memory configured to hold cache data using a virtual page tag or a page offset as a cache index; a cache state memory configured to hold a cache state for the cache data stored in the data memory, in association with the cache index; a first physical address memory configured to, when the rewrite to the TLB occurs, rewrite a held physical address; and a second physical address memory configured to, when the cache data is written to the data memory after the occurrence of the rewrite to the TLB, rewrite a held physical address.

Abstract: Disclosed is a computer system (100) comprising a processor unit (110) adapted to run a virtual machine in a first operating mode; a cache (120) accessible to the processor unit, said cache including a cache controller (122); and a memory (140) accessible to the cache controller for storing an image of said virtual machine; wherein the processor unit is adapted to create a log (200) in the memory prior to running the virtual machine in said first operating mode; the cache controller is adapted to transfer a modified cache line from the cache to the memory; and write only the memory address of the transferred modified cache line in the log; and the processor unit is further adapted to update a further image of the virtual machine in a different memory location, e.g. on another computer system, by retrieving the memory addresses stored in the log, retrieve the modified cache lines from the memory addresses and update the further image with said modifications.

Abstract: A system and method of detecting cache inconsistencies among distributed data centers is described. Key-based sampling captures a complete history of a key for comparing cache values across data centers. In one phase of a cache inconsistency detection algorithm, a log of operations performed on a sampled key is compared in reverse chronological order for inconsistent cache values. In another phase, a log of operations performed on a candidate key having inconsistent cache values as identified in the previous phase is evaluated in near real time in forward chronological order for inconsistent cache values. In a confirmation phase, a real time comparison of actual cache values stored in the data centers is performed on the candidate keys identified by both the previous phases as having inconsistent cache values. An alert is issued that identifies the data centers in which the inconsistent cache values were reported.

Abstract: A method and apparatus for state encoding of cache lines is described. Some embodiments of the method and apparatus support probing, in response to a first probe of a cache line in a first cache, a copy of the cache line in a second cache when the cache line is stale and the cache line is associated with a copy of the cache line stored in the second cache that can bypass notification of the first cache in response to modifying the copy of the cache line.