Abstract: Apparatus for a garbage collection is disclosed herein. The apparatus includes a processor that includes a load-monitored region register. A memory stores program code, which, when executed on the processor performs an operation for garbage collection, the operation includes specifying a load-monitored region within a memory managed by a runtime environment; enabling a load-monitored event-based branch configured to occur responsive to executing a first type of CPU instruction to load a pointer that points to a first location in the load-monitored region; performing a garbage collection process in background without pausing executing in the runtime environment; executing a CPU instruction of the first type to load a pointer that points to the first location in the load-monitored region; responsive to triggering a load-monitored event-based branch, moving an object pointed to by the pointer with a handler from the first location in memory to a second location in memory.

Abstract: Modifying prefetch request processing. A prefetch request is received by a local computer from a remote computer. The local computer responds to a determination that execution of the prefetch request is predicted to cause an address conflict during an execution of a transaction of the local processor by determining an evaluation of the prefetch request prior to execution of the program instructions included in the prefetch request. The evaluation is based, at least in part, on (i) a comparison of a priority of the prefetch request with a priority of the transaction and (ii) a condition that exists in one or both of the local processor and the remote processor. Based on the evaluation, the local computer modifies program instructions that govern execution of the program instructions included in the prefetch request.

Abstract: Techniques relate to handling outstanding cache miss prefetches. A processor pipeline recognizes that a prefetch canceling instruction is being executed. In response to recognizing that the prefetch canceling instruction is being executed, all outstanding prefetches are evaluated according to a criterion as set forth by the prefetch canceling instruction in order to select qualified prefetches. In response to evaluating, a cache subsystem is communicated with to cause canceling of the qualified prefetches that fit the criterion. In response to successful canceling of the qualified prefetches, a local cache is prevented from being updated from the qualified prefetches.

Abstract: An apparatus includes a processor and a virtual address transformation unit coupled with the processor. The virtual address transformation unit includes a register. The virtual address transformation unit is configured to receive an indication of a virtual address and read, from the register, a current page size of a plurality of available page sizes. The virtual address transformation unit is also configured to determine a shift amount based, at least in part, on the current page size and perform a bit shift of the virtual address, wherein the virtual address is bit shifted by, at least, the determined shift amount.

Abstract: A method and associated computer program product are disclosed for generating an executable file from an object file comprising a function that references a table of contents (TOC) pointer register. The method comprises identifying, based on at least one first annotation included in the object file, at least one instruction of the function having an eliminable reference to the TOC pointer register, and determining, during a linking of the object file and based on the at least one first annotation, whether to eliminate the eliminable reference.

Abstract: Embodiments relate to using a local entry point with an indirect call function. More specifically, an indirect call function configuration comprises a first application module having a target function of the indirect function call, a second application module with a symbolic reference to the target function of the indirect function call, and a third application module to originate an indirect function call. A compiler determines and indicates, in the program code, that the function pointer value resulting from a non-call reference of a function symbol is solely used to perform indirect calls in the same module, e.g. local-use-only. A linker or loader can read the indication the compiler made in the program code. The linker or loader use the local entry point associated with the target function if the target function is defined in the same module as the reference and is local-use-only.

Abstract: When executed, a transaction-hint instruction specifies a transaction-count-to-completion (CTC) value for a transaction. The CTC value indicates how far a transaction is from completion. The CTC may be a number of instructions to completion or an amount of time to completion. The CTC value is adjusted as the transaction progresses. When a disruptive event associated with inducing transactional aborts, such as an interrupt or a conflicting memory access, is identified while processing the transaction, processing of the disruptive event is deferred if the adjusted CTC value satisfies deferral criteria. If the adjusted CTC value does not satisfy deferral criteria, the transaction is aborted and the disruptive event is processed.

Abstract: Autonomous recovery from a transient hardware failure by executing portions of a stream of program instructions as a transaction. A start of a transaction is created in a stream of program instructions executing on a first processor of a multi-processor computer. A snapshot of a system state information is saved when the transaction begins. When the transaction ends, store data of the transaction is committed. If a transient hardware failure occurs, the transaction is aborted without notifying the computer software application that initiated the stream of program instructions. The transaction is re-executed on a second processor of the multi-processors, based on the saved snapshot of the system state information.

Abstract: Autonomous recovery from a transient hardware failure by executing portions of a stream of program instructions as a transaction. A start of a transaction is created in a stream of executing program instructions. A snapshot of a system state information is saved when the transaction begins. When a predefined number of program instructions in the stream are executed, the transaction ends, and store data of the transaction is committed. A new transaction then begins. If a transient hardware failure occurs, the transaction is aborted without notifying the computer software application that initiated the stream of program instructions. The transaction is re-executed, based on the saved snapshot of the system state information.

Abstract: A method and associated computer program product are disclosed for generating an object file for subsequent linking by a linker. The object file comprises a function that references a table of contents (TOC) pointer register. The method comprises generating, in the object file, at least one first annotation that identifies at least one instruction of the function. The at least one instruction has an eliminable reference to the TOC pointer register. The first annotation configures the linker to determine, during the subsequent linking of the object file and based on the at least one first annotation, whether to eliminate the eliminable reference.

Abstract: An optimizing compiler includes a vector optimization mechanism that optimizes vector operations that are reformatting-resistant, such as source instructions that do not have a corresponding reformatting operation, sink instructions that do not have a corresponding reformatting operation, a source instruction that is a scalar value, a sink instruction that may produce a scalar value, and an internal operation that depends on lanes being in a specified order. The ability to optimize vector instructions that are reformatting-resistant reduces the number of operations to improve the run-time performance of the code.

Abstract: In an approach for resolving terminated transactions in a transactional memory environment, a processor initiates a hardware transaction in a computing environment, wherein the hardware transaction accesses a memory location, and wherein the hardware transaction includes a transaction begin indicator and a transaction end indicator. A processor detects a conflicting access of the memory location while executing the hardware transaction. A processor aborts the hardware transaction based on the conflicting access of the memory location. Hardware determines that the conflicting access of the memory location is a transient condition. A processor reinitiates the hardware transaction.

Abstract: A compiler includes a vector instruction processing mechanism that generates instructions for vector instructions in a way that assures correct operation in a bi-endian environment, wherein the processor architecture contains instructions with an inherent endian bias, along with at least one memory access instruction with a contrary endian bias. The compiler uses a code generation endian preference that matches the inherent computer system endian bias. The compiler generates instructions for vector instructions by determining whether the vector instruction has an endian bias that matches the code generation endian preference. When the endian bias of the vector instruction matches the code generation endian preference, the compiler generates one or more instructions for the vector instruction as normal.

Abstract: A computer can manage an interruption while a processor is executing a transaction in a transactional-execution (TX) mode. Execution, in a program context, of the transaction is begun by a processor in TX mode. An interruption request is detected for an interruption, by the processor, in TX mode. The interruption is accepted by the processor to execute a TX compatible routine in a supervisor context for changing supervisor resources. The TX compatible routine is executed within the TX mode. The processor returns to the program context to complete the execution of the transaction. Based on the transaction aborting, the processor does not commit changes to the supervisor resources.

Abstract: Embodiments relate to using a local entry point with an indirect call function. More specifically, an indirect call function configuration comprises a first application module having a target function of the indirect function call, a second application module with a symbolic reference to the target function of the indirect function call, and a third application module to originate an indirect function call. A compiler is provided to determine and indicate in the program code that the function pointer value resulting from a non-call reference of a function symbol is solely used to perform indirect calls in the same module, e.g. local-use-only. A linker or loader can read the indication the compiler made in the program code. The linker or loader use the local entry point associated with the target function if the target function is defined in the same module as the reference and is local-use-only.

Abstract: The embodiments relate to a method for managing a garbage collection process. The method includes executing a garbage collection process on a memory block of user address space. A load instruction is run. Running the load instruction includes loading content of a storage location into a processor. The loaded content corresponds to a memory address. It is determined if the garbage collection process is being executed at the memory address. The load instruction is diverted to a process to move an object at the memory address to a location outside of the memory block in response to determining that the garbage collection process is being executed at the first memory address. The load instruction is continued in response to determining that the garbage collection process is not being executed at the memory address.

Abstract: Embodiments relate to using a local entry point with an indirect call function. More specifically, an indirect call function configuration comprises a first application module having a target function of the indirect function call, a second application module with a symbolic reference to the target function of the indirect function call, and a third application module to originate an indirect function call. A compiler is provided to determine and indicate in the program code that the function pointer value resulting from a non-call reference of a function symbol is solely used to perform indirect calls in the same module or comparisons against function pointers. A linker or loader can read the indication the compiler made in the program code. The linker or loader use the local entry point associated with the target function if the target function is defined in the same module as the reference and is local-use-only.

Abstract: Prevention of a prefetch memory operation from causing a transaction to abort. A local processor receives a prefetch request from a remote processor. Prior to execution of the prefetch request, a processor determines whether the prefetch request conflicts with a transaction of the local processor. A processor responds to a determination that the priority of the remote processor is greater than priority of the local processor by (i) aborting the transaction (ii) executing the prefetch request, and (iii) providing requested prefetch data to the remote processor.

Abstract: Prevention of a prefetch memory operation from causing a transaction to abort. A local processor receives a prefetch request from a remote processor. Prior to execution of the prefetch request, a processor determines whether the prefetch request conflicts with a transaction of the local processor. A processor responds to a determination that the priority of the prefetch request is greater than priority of the transaction, by (i) aborting the transaction (ii) executing the prefetch request, and (iii) providing requested prefetch data to the remote processor.

Abstract: Embodiments relate to application-level processor parameter management. An aspect includes granting, by a hypervisor of a computer system, access to an operating parameter of a processor of the computer system to an application that is running on the computer system. Another aspect includes, based on the granting of access to the operating parameter, receiving, by an optimization function in the computer system from the application, a request to adjust the operating parameter. Another aspect includes determining an adjusted value for the operating parameter during execution of the application. Another aspect includes setting the operating parameter to the adjusted value in a parameter register of the processor. Another aspect includes executing the application according to the parameter register by the processor.