Abstract: A cluster of processing elements has a split mode in which the processing elements are configured to process independent processing workloads, and a lock mode in which the processing elements comprise at least one primary processing element and at least one redundant processing element, each redundant processing element configured to perform a redundant processing workload for checking an outcome of a primary processing workload performed by a corresponding primary processing element. A shared cache is provided, having a predetermined cache capacity accessible to each of the processing elements when in the split mode. In the lock mode, the predetermined cache capacity of the shared cache is fully accessible to the at least one primary processing element.

Abstract: A cluster of processing elements has a split mode in which the processing elements are configured to process independent processing workloads, and a lock mode in which the processing elements comprise at least one primary processing element and at least one redundant processing element, each redundant processing element configured to perform a redundant processing workload for checking an outcome of a primary processing workload performed by a corresponding primary processing element. A shared cache is provided, having a predetermined cache capacity accessible to each of the processing elements when in the split mode. In the lock mode, the predetermined cache capacity of the shared cache is fully accessible to the at least one primary processing element.

Abstract: Systems and techniques relating to hardware alias detection and management in caches are described. A cache controller can receive a cache request that specifies a virtual address, which includes a virtual page number (VPN) and a page offset; access, concurrently, one or more primary tags in a slot of the cache corresponding to a primary cache index that is based on a portion of the page offset and a portion of the VPN and one or more secondary tags in one or more slots corresponding to one or more secondary cache indices that are based on the portion of the page offset and one or more variations of the portion of the VPN; and determine whether there are any primary or secondary matching ways. The controller can write store data to a primary matching way if it exists and perform an alias management operation if any secondary matching ways exist.

Abstract: A method can include executing a store instruction that instructs storing of data at an address and, in response to the store instruction, inserting a preloading instruction after the store instruction but before a dependent load instruction to the address. Executing the store instruction can include invalidating a data entry of a cache array at an address of the cache array corresponding to the address and writing the data to a backing memory at an address of the backing memory corresponding to the address. The preloading instruction can cause filling the data entry of the cache array, at the address of the cache array corresponding to the address, with the data from the backing memory at the address of the backing memory corresponding to the address and validating the data entry of the cache array.

Abstract: A circuit includes a Virtually Indexed Physically Tagged (VIPT) cache and a cache coherency circuit. The VIPT cache includes a plurality of sets and performs a memory operation by selecting, using a Virtual Set Address (VSA), a first tag of a first set. The cache coherency circuit is to detect cache aliasing during memory operations of the VIPT cache when a second tag maps a physical address to a second set of the VIPT cache, the second set being different than the first set. A method of managing a VIPT cache includes performing, by the VIPT cache, a memory operation and determining, using a cache coherency protocol, that cache aliasing has occurred during the memory operation.

Abstract: A microprocessor includes a front end module and a schedule queue module. The front end module is configured to retrieve first instructions, corresponding to a first thread, from an instruction cache, and retrieve second instructions, corresponding to a second thread, from the instruction cache. The front end module is also configured to decode the first instructions into first decoded instructions, and decode the second instructions into second decoded instructions. The schedule queue module is configured to selectively store the first decoded instructions and the second decoded instructions from the front end module and, for each stored decoded instruction, selectively issue the stored decoded instruction to an execution module. The schedule queue is further configured to reject storing an additional one of the first decoded instructions from the front end module in response to a count of the stored first decoded instructions in the schedule queue module exceeding a threshold.

Abstract: Apparatus having corresponding methods and computer-readable media comprise: a speculative store buffer memory; and a speculative store buffer controller comprising a store address comparator to compare an address of a received store instruction with addresses of store instructions allocated in the speculative store buffer memory, and a store age comparator to compare an age of the received store instruction with an age of a matching store instruction allocated in the speculative store buffer memory, wherein the speculative store buffer controller replaces the store instruction allocated in the speculative store buffer memory with the received store instruction responsive to the store instruction allocated in the speculative store buffer memory being younger than the received store instruction.

Abstract: A cache management unit manages allocation and configuration of a cache memory that is utilized by a multi-threaded processor. In some implementations, the cache management unit is configured to determine a number of active threads being executed by the multi-threaded processor, assign a separate cache unit to each active thread when the number of active threads is equal to a maximum number of active threads supported by the multi-threaded processor, and assign more than one cache unit to an active thread when the number of active threads is less than the maximum number of active threads.

Abstract: Systems and methods for writing data from a caching agent to a main memory in a computer system are provided. In systems and methods for writing data from a caching agent to a main memory in a computer system, a notice of an occurrence of a triggering event is received. In response to the receipt of the notice, data is retrieved from a storage array of the caching agent in accordance with a pre-clean criterion. The pre-clean criterion identifies the data that is being retrieved from the storage array prior to receiving a command on the data. The data is written to the main memory, where the writing of the data causes a memory address associated with the data to have identical contents in the storage array and in the main memory.

Abstract: Systems, methods, and other embodiments associated with reducing interrupt latency are described. According to one embodiment, an apparatus includes a buffer storing instructions awaiting execution by an execution device. The apparatus also includes an interrupt logic that, in response to receiving an interrupt, classifies instructions as either safe or unsafe. An unsafe instruction will cause the instructions to execute in a manner inconsistent with an instruction set architecture. The interrupt logic also establishes an interrupt boundary between safe and unsafe instructions, and causes the interrupt to be processed at the interrupt boundary such that the interrupt is processed before processing of the unsafe instructions.

Abstract: A system and method of tracking multiple non-identification tagged requests in a system with multiple responders are disclosed. In one embodiment, an electronic memory system comprises a memory configured to implement a plurality of response queues, wherein one response queue is associated with one responder from a plurality of responders, and wherein a responder is a device capable of resolving the memory request. A tracking module is configured to assign identification information to a memory request that is received and store the identification information in one or more queues of the plurality of response queues; and to transmit the memory request to each responder that is associated with the one or more queues. A response module is configured to associate the identification information in the one or more queues with a response upon receiving the response from the one or more responders.

Abstract: A processor for processing loop instructions can include an instruction reorder structure and a loop processing controller. The instruction reorder structure is configured to store decoded instructions according to program order and issue the decoded instructions for execution out of program order. The loop processing controller is configured to detect a loop in the decoded instructions stored in the instruction reorder structure and cause the instruction reorder structure to reissue the decoded instructions that form the loop for re-execution.

Abstract: Devices, systems, methods, and other embodiments associated with a cache memory are described. In one embodiment, a cache tag array includes tag banks. The cache memory further includes a bank selector configured to receive an address and to apply a hash function that maps the address to one of the tag banks.

Abstract: Aspects of the disclosure provide methods for cache efficiency. A method for cache efficiency can include storing data in a buffer entry in association with a cache array in response to a first store instruction that hits the cache array before the first store instruction is committed. Further, when a dependent load instruction is subsequent to the first store instruction, the method can include providing the data from the buffer entry in response to the first dependent load instruction. When a second store instruction overlaps an address of the first store instruction, the method can include coalescing data of the second store instruction in the buffer entry before the second store instruction is committed. When the second store instruction is followed by a second dependent load instruction, the method can include providing the coalesced data from the buffer entry in response to the second dependent load instruction.

Abstract: A processor that executes instructions out of program order is described. In some implementations, a processor detects whether a second memory operation is dependent on a first memory operation prior to memory address calculation. If the processor detects that the second memory operation is not dependent on the first memory operation, the processor is configured to allow the second memory operation to be scheduled. If the processor detects that the second memory operation is dependent on the first memory operation, the processor is configured to prevent the second memory operation from being scheduled until the first memory operation has been scheduled to reduce the likelihood of having to reexecute the second memory operation.

Abstract: According to some embodiments, an apparatus having corresponding methods includes a storage module configured to store data and instructions; a first processor pipeline configured to process the data and instructions when the first processor pipeline is selected; a second processor pipeline configured to process the data and instructions when the second processor pipeline is selected; and a selection module configured to select either the first processor pipeline or the second processor pipeline.

Abstract: A programmable cache and cache access protocol that can be dynamically optimized with respect to either power consumption or performance based on a monitored performance of the cache. A monitoring unit monitors cache misses, load use penalty, and/or other performance parameter, and compares the monitored values against a set of one or more predetermined thresholds. Based on the comparison results, a cache controller configures the programmable cache to operate in a parallel mode, to increase cache performance at the cost of greater power consumption, or in a serial mode, to conserve power at the cost of unnecessary performance. A banked cache memory that supports aligned and unaligned instruction fetches using a banked access strategy, and a cache access controller that includes a prefetch capability are also described.

Abstract: A system and method of tracking multiple non-identification tagged requests in a system with multiple responders using one or more tracking queues. In some embodiments, the system and method may be implemented in a snoop filter covering multiple caches. In some embodiments, a data-less bus query may be used to update the status of a requested line.

Abstract: Set-associative caches having corresponding methods and computer programs comprise: a data cache to provide a plurality of cache lines based on a set index of a virtual address, wherein each of the cache lines corresponds to one of a plurality of ways of the set-associative cache; a translation lookaside buffer to provide one of a plurality of way selections based on the set index of the virtual address and a virtual tag of the virtual address, wherein each of the way selections corresponds to one of the ways of the set-associative cache; and a way multiplexer to select one of the cache lines provided by the data cache based on the one of the plurality of way selections.

Abstract: Non-processor agents, such as bus agents, may directly access processor caches. A coherency protocol ensures that cache coherency is maintained.