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: Predicting a Table of Contents (TOC) pointer value responsive to branching to a subroutine. A subroutine is called from a calling module executing on a processor. Based on calling the subroutine, a value of a pointer to a reference data structure, such as a TOC, is predicted. The predicting is performed prior to executing a sequence of one or more instructions in the subroutine to compute the value. The value that is predicted is used to access the reference data structure to obtain a variable value for a variable of the subroutine.

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. Based on determining that the rate is to be changed, the rate of prefetching is changed.

Abstract: One or more architected registers are restored from a snapshot previously taken of the one or more architected registers. The snapshot indicates one or more physical registers previously assigned to the one or more architected registers. The restoring replaces the one or more physical registers currently assigned to the one or more architected registers with the one or more physical registers previously assigned to the one or more architected registers as indicated by the snapshot. A determination is made as to the validity of the one or more architected registers restored using the snapshot. The determining validity includes checking memory locations associated with the one or more architected registers to determine whether contents of the one or more architected registers have changed since the snapshot was taken. If the contents of the one or more architected registers have not changed, the one or more architected registers are valid.

Abstract: Single hypervisor call to perform pin and unpin operations. A hypervisor call relating to the pinning of units of memory is obtained. The hypervisor call specifies an unpin operation for a first memory address and a pin operation for a second memory address. Based on obtaining the hypervisor call, at least one of the unpin operation for the first memory address and the pin operation for the second memory address is performed.

Abstract: Corruption of program stacks is detected by using guard words placed in the program stacks. A called routine executing on a processor checks a guard word in a stack of a calling routine. The checking determines whether the guard word has an expected value. Based on determining the guard word has an unexpected value, an indication of corruption of the stack is provided. Some routines, however, may not support use of guard words. Thus, routines that are interlinked may have differing protection capabilities. A determination is made as to the differing protection capabilities, an indication of the same is provided, and the routines are executed without failing due to the differing protection capabilities.

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. Based on determining that the rate is to be changed, the rate of prefetching is changed.

Abstract: Address translation of a base address prior to receiving a storage reference to use the address. A determination is made that an address has been obtained that is to be used as a base address for a memory location at which one or more in-memory configuration state registers are stored. Based on the determining, the address is translated into another address, and the translating is performed prior to receiving a storage reference to use the base address.

Abstract: Sharing snapshots between restoration and recovery. A snapshot to be used for recovery and restoration is obtained. The snapshot includes restoration state for a plurality of architected registers. The plurality of architected registers includes one or more architected registers associated with an instruction to alter an execution path and one or more architected registers associated with a save request. At least one architected register of the plurality of architected registers is restored, based on a request. The request is a recovery request to recover at least one architected register associated with the instruction to alter the execution path or a restoration request to restore at least one architected register associated with the save request.

Abstract: A determination is made that a unit of memory that provides storage for one or more in-memory configuration state registers is to be pinned in a system that includes a guest operating system and one or more hosts at one or more host levels. Based on determining that the unit of memory is to be pinned, at least one host of the one or more hosts is notified that the unit of memory is to be pinned.

Abstract: Processing of prefetched data based on cache residency. Data to be used in future processing is prefetched. A block of data being prefetched is selected for processing, and a check is made as to whether the block of data is resident in a selected cache (e.g., L1 cache). If the block of data is resident in the selected cache, it is processed; otherwise, processing is bypassed until a later time when it is resident in the selected cache.

Abstract: Predicting a Table of Contents (TOC) pointer value responsive to branching to a subroutine. A subroutine is called from a calling module executing on a processor. Based on calling the subroutine, a value of a pointer to a reference data structure, such as a TOC, is predicted. The predicting is performed prior to executing a sequence of one or more instructions in the subroutine to compute the value. The value that is predicted is used to access the reference data structure to obtain a variable value for a variable of the subroutine.

Abstract: A Set Boolean machine instruction is provided that has associated therewith a result location to be used for a set Boolean operation and a mask. The mask is configured to test a plurality of types of conditions, including simple conditions and composite conditions. The machine instruction is executed, and the executing includes performing a first logical operation between the mask and contents of a selected field to obtain an output. The mask indicates a condition to be tested, and the condition is one type of condition of the plurality of types of conditions. The executing further includes performing a second logical operation on the output to obtain a first value represented as one data type, and placing a result in the result location based on the first value. The result including a second a value of another data type, the other data type being different from the one data type.

Abstract: An instruction defined to be a looping instruction that repeats a plurality of times to perform an operation on a defined amount of data is obtained. The looping instruction is expanded into a sequence of operations. The sequence of operations is a non-looping sequence of operations to perform the operation on the defined amount of data.

Abstract: An instruction architecturally defined to be a looping instruction, in which a loop is configured to repeat a plurality of times to perform an operation on up to a defined number of units of data, is to be processed. The processing includes replicating a selected character a number of times to provide a replicated selected character, and using a sequence of operations to perform the operation, the sequence of operations replacing the loop and providing a non-looping sequence to perform the operation on up to the defined number of units of data. The sequence of operations is configured to repeat one or more times, and to terminate based on the replicated selected character.

Abstract: A Set Boolean machine instruction is provided that has associated therewith a result location to be used for a set Boolean operation and a mask. The mask is configured to test a plurality of types of conditions, including simple conditions and composite conditions. The machine instruction is executed, and the executing includes performing a first logical operation between the mask and contents of a selected field to obtain an output. The mask indicates a condition to be tested, and the condition is one type of condition of the plurality of types of conditions. The executing further includes performing a second logical operation on the output to obtain a first value represented as one data type, and placing a result in the result location based on the first value. The result including a second a value of another data type, the other data type being different from the one data type.

Abstract: Transient mode for an application is toggled. Transient mode for an application executing in the computing environment is activated. Based on activating transient mode for the application, a plurality of memory accesses are processed as transient accesses. Based on processing the plurality of memory accesses, transient mode for the application is deactivated.

Abstract: Register restoration using transactional memory register snapshots. An indication that a transaction is to be initiated is obtained. Based on obtaining the indication, a determination is made as to whether register restoration is in active use. Based on obtaining the indication and determining register restoration is in active use, register restoration is deactivated. To recover one or more architected registers of the transaction, a transactional rollback snapshot is created.

Abstract: Short pointer mode applications are able to execute in long pointer mode environments. A plurality of actions is performed to prepare a short pointer mode application for execution in the long pointer mode environment. These actions include allocating memory for one or more in-memory short pointers of the application. The memory being allocated for an in-memory short pointer is of a size corresponding to a size of the in-memory short pointer. Further, a register is allocated for an in-register short pointer of the application. The register is allocated at a size corresponding to a long pointer mode. The size corresponding to the long pointer mode is different from the size of the in-memory short pointer.

Abstract: Portions of configuration state registers in-memory. An instruction is obtained, and a determination is made that the instruction accesses a configuration state register. A portion of the configuration state register is in-memory and another portion of the configuration state register is in-processor. Processing associated with the configuration state register is performed. The performing processing is based on a type of access and whether the portion or the other portion is being accessed.