Abstract: Controlling a rate of prefetching based on bus bandwidth. A determination is made as to whether a rate of prefetching data from memory into a cache is to be changed. This determination is based on bus utilization, and includes identifying a most utilized bus of a plurality of buses used for the prefetch of data, and monitoring utilization of the most utilized bus. The determination whether the rate of prefetching is to be changed is based on the monitoring. Based on determining that the rate is to be changed, the rate of prefetching is changed.

Abstract: A method, system, and computer program product are provided for prioritizing prefetch instructions. The method includes a processor issuing a prefetch instruction and fetching elements from a cache that can include a memory or a higher level cache. The processor stores the elements in temporary storage and monitors for accesses by an instruction. The processor stores a record representing the prefetch instruction. The processor updates the record with an indicator and issues a new prefetch instruction by comparing the new prefetch instruction to the record, based on the new prefetch instruction matching the prefetch instruction, assigning the indicator to the new prefetch instruction as a priority value, based on the new prefetch instruction not matching the prefetch instruction, assigning a default value to the new prefetch instruction as the priority value, and determining whether to execute the new prefetch instruction, based on the priority value of the new prefetch instruction.

Abstract: A data processor comprising a plurality of registers, and instruction execution circuitry having an associated instruction set, wherein the instruction set includes an instruction specifying at least a mask operand, a register operand and an immediate value operand, and the instruction execution circuitry, in response to an instance of the instruction, determines a Boolean value based on the mask operand and sets a respective one of a plurality of registers specified by the register operand of the instance to a value of the immediate value operand if the Boolean value is true. The instruction execution circuitry, in response to the instance of the instruction, may set the respective one of the plurality of registers specified by the register operand of the instance to zero if the Boolean value is false.

Abstract: A method, computer program product, and system performing a method that include a processor defining a code fingerprint by obtaining parameters describing at least one of an event type or an event. The code fingerprint includes a first sequence. The processor loads the code fingerprint into a register accessible to the processor. Concurrent with executing a program, the processor obtains the code fingerprint from the register and identifies the code fingerprint in the program by comparing a second sequence in the program to the first sequence. Based on identifying the code fingerprint in the program, the processor alerts a runtime environment where the program is executing.

Abstract: Register restoration using recovery buffers. A restore request initiated by an application to restore one or more registers indicated by the restore request is obtained. The one or more registers are restored using a recovery buffer. The restoring scans the recovery buffer for the one or more registers indicated by the restore request, and restores the one or more registers using one or more values obtained from the recovery buffer.

Abstract: A method and a system detects a cache line as a potential or confirmed hot cache line based on receiving an intervention of a processor associated with a fetch of the cache line. The method and system include suppressing an action of operations associated with the hot cache line. A related method and system detect an intervention and, in response, communicates an intervention notification to another processor. An alternative method and system detect a hot data object associated with an intervention event of an application. The method and system can suppress actions of operations associated with the hot data object. An alternative method and system can detect and communicate an intervention associated with a data object.

Abstract: A method, system, and computer program product are provided for prioritizing prefetch instructions. The method includes a processor issuing a prefetch instruction and fetching elements from a cache that can include a memory or a higher level cache. The processor stores the elements in temporary storage and monitors for accesses by an instruction. The processor stores a record representing the prefetch instruction. The processor updates the record with an indicator and issues a new prefetch instruction by comparing the new prefetch instruction to the record, based on the new prefetch instruction matching the prefetch instruction, assigning the indicator to the new prefetch instruction as a priority value, based on the new prefetch instruction not matching the prefetch instruction, assigning a default value to the new prefetch instruction as the priority value, and determining whether to execute the new prefetch instruction, based on the priority value of the new prefetch instruction.

Abstract: A transaction is detected. The transaction has a begin-transaction indication and an end-transaction indication. If it is determined that the begin-transaction indication is not a no-speculation indication, then the transaction is processed.

Abstract: Processing of a storage operand request identified as restrained is selectively, temporarily suppressed. The processing includes identifying a storage operand request as restrained, where the identifying includes obtaining, by a processing unit, an access intent instruction indicating an access intent associated with an operand of a next sequential instruction. The access intent indicates usage of the storage operand request is restrained. Further, the method includes determining whether a storage operand request is to a common storage location shared by multiple processing units of a computing environment and is identified restrained, and based on determining that the storage operand request is restrained, then temporarily suppressing requesting access to the common storage location pursuant to the storage operand request.

Abstract: Processing of a storage operand request identified as restrained is selectively, temporarily suppressed. The processing includes determining whether a storage operand request to a common storage location shared by multiple processing units of a computing environment is restrained, and based on determining that the storage operand request is restrained, then temporarily suppressing requesting access to the common storage location pursuant to the storage operand request. The processing unit performing the processing may proceed with processing of the restrained storage operand request, without performing the suppressing, where the processing can be accomplished using cache private to the processing unit. Otherwise the suppressing may continue until an instruction, or operation of an instruction, associated with the storage operand request is next to complete.

Abstract: A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Abstract: Providing control over processing of a prefetch request in response to conditions in a receiver of the prefetch request and to conditions in a source of the prefetch request. A processor generates a prefetch request and a tag that dictates processing the prefect request. A processor sends the prefetch request and the tag to a second processor. A processor generates a conflict indication based on whether a concurrent processing of the prefetch request and an atomic transaction by the second processor would generate a conflict with a memory access that is associated with the atomic transaction. Based on an analysis of the conflict indication and the tag, a processor processes (i) either the prefetch request or the atomic transaction, or (ii) both the prefetch request and the atomic transaction.

Abstract: Processing prefetch memory operations and transactions. A local processor receives a write prefetch request from a remote processor. Prior to execution of a write prefetch request received from a remote processor, determining whether a priority of the write prefetch request is greater than a priority of a pending transaction of a local processor. The write prefetch request is executed in response to a determination that the priority of the write prefetch request is greater than the priority of a pending transaction. Prefetch data produced by execution of the write prefetch request is provided to the remote processor.

Abstract: In a transactional memory environment including a first processor and one or more additional processors, a computer-implemented method includes identifying a memory location and sending a probe request from the first processor to the additional processors. The probe request includes the memory location. The computer implemented method further includes generating, by each additional processor, an indication including whether the memory location is in use for a transaction by the additional processor. The computer-implemented method further includes sending the indication from each additional processor to the first processor and proceeding, by the first processor, based on the indication.

Abstract: A load request to restore a plurality of architected registers is obtained. Based on obtaining the load request, one or more architected registers of the plurality of architected registers are restored. The restoring uses a snapshot that maps architected registers to physical registers to replace one or more physical registers currently assigned to the one or more architected registers with one or more physical registers of the snapshot corresponding to the one or more architected registers.

Abstract: A computer implemented method for marking a store instruction overlap in a processor pipeline is provided. A non-limiting example of the method includes detecting a second store instruction subsequent to a first store instruction in an instruction stream, in which there is a match between the operand address information of the first store instruction and a load instruction. The operand address information of the first store instruction is compared with the operand address information of the second store instruction to determine whether there is match. In the event of a match, the second store instruction is delayed in the processor pipeline in response to determining that there is a memory image overlap between the operand address information of the second store instruction and the first store instruction.

Abstract: A reload multiple instruction is used to restore a set of architected registers saved by a spill multiple instruction. The reload multiple instruction is executed, and the executing includes determining the set of architected registers to be restored, which is specified by the reload multiple instruction. The set of architected registers is restored from a selected snapshot that maps architected registers to physical registers. The restoring replaces one or more physical registers currently assigned to one or more architected registers of the set of architected registers with one or more physical registers of the selected snapshot corresponding to the set of architected registers.

Abstract: A shared cache line is concurrently modified by multiple processors of a computing environment. The concurrent modification is performed based, at least, on receiving one or more architected instructions (Fetch due to Non-Coherent Store instructions) that permit multiple processors to concurrently update the shared cache line absent obtaining a lock or having exclusive ownership of the data.

Abstract: Transactional memory accesses are tracked using read and write sets based on actual program flow. A read and write set is associated with a range of instructions of a transaction. When execution follows a predicted branch, loads and stores are marked as being of selected read and write sets. Then, when a misprediction is processed, and execution is rewound, speculatively added read and write set indications are removed from the read and write sets.

Abstract: Transactional memory accesses are tracked using read and write sets based on actual program flow. A read and write set is associated with a range of instructions of a transaction. When execution follows a predicted branch, loads and stores are marked as being of selected read and write sets. Then, when a misprediction is processed, and execution is rewound, speculatively added read and write set indications are removed from the read and write sets.