Abstract: Embodiments of the invention relate to enabling and disabling execution of a run-time instrumentation facility. An instruction for execution by the processor in a lesser privileged state is fetched by the processor. It is determined, by the processor, that the run-time instrumentation facility permits execution of the instruction in the lesser-privileged state and that controls associated with the run-time instrumentation facility are valid. The run-time instrumentation facility is disabled based on the instruction being a run-time instrumentation facility off (RIOFF) instruction. The disabling includes updating a bit in a program status word (PSW) of the processor to indicate that run-time instrumentation data should not be captured by the processor. The run-time instrumentation facility is enabled based on the instruction being a run-time instrumentation facility on (RION) instruction.

Abstract: Embodiments of the invention relate to performing run-time instrumentation. Run-time instrumentation is captured, by a processor, based on an instruction stream of instructions of an application program executing on the processor. The capturing includes storing the run-time instrumentation data in a collection buffer of the processor. A run-time instrumentation sample point trigger is detected by the processor. Contents of the collection buffer are copied into a program buffer as a reporting group based on detecting the run-time instrumentation sample point trigger. The program buffer is located in main storage in an address space that is accessible by the application program.

Abstract: Embodiments of the invention relate to executing a run-time-instrumentation EMIT (RIEMIT) instruction. A processor is configured to capture the run-time-instrumentation information of a stream of instructions. The RIEMIT instruction is fetched and executed. It is determined if the current run-time-instrumentation controls are configured to permit capturing and storing of run-time-instrumentation information in a run-time-instrumentation program buffer. If the controls are configured to store run-time-instrumentation instructions, then a RIEMIT instruction specified value is stored as an emit record of a reporting group in the run-time-instrumentation program buffer.

Abstract: Embodiments of the invention relate to performing run-time instrumentation. Run-time instrumentation is captured, by a processor, based on an instruction stream of instructions of an application program executing on the processor. The capturing includes storing the run-time instrumentation data in a collection buffer of the processor. A run-time instrumentation sample point trigger is detected by the processor. Contents of the collection buffer are copied into a program buffer as a reporting group based on detecting the run-time instrumentation sample point trigger. The program buffer is located in main storage in an address space that is accessible by the application program.

Abstract: Optimizing a program having a plurality of functions using an optimization technique that requires breaking a calling convention. A first function of the plurality of functions is modified as a result of optimizing. A name of the first function is mangled to form a unique first mangled name changing the name of the first function to include, as a result of mangling, first information conveying at least in part how the first function was modified. A second function of the plurality of functions, being a caller of the first function, is also modified to correctly invoke the first function using the unique first mangled name to apply the optimization technique. A compilation tool can, after optimizing, use the first information to take a first action with respect to the first procedure, wherein the compilation tool otherwise would require the calling convention to remain unbroken to take the first action.

Abstract: A mechanism is provided for operating a computing system, in which an inner virtual machine translates first instructions, which are supported by the inner virtual machine, into second instructions, which are supported by an outer virtual machine. The mechanism encodes, in the inner virtual machine, third instructions into the second instructions into which the first instructions are translated, the third instructions including hints for facilitating an execution of the second instructions, and, in an event the hints are supported by the outer virtual machine, initiating the execution of the second instructions while utilizing the hints by the outer virtual machine to achieve an increased efficiency of the execution of the second instructions.

Abstract: Embodiments of the present invention address deficiencies of the art in respect to pattern matcher generation and provide a method, system and computer program product for automatic pattern matching and generation of intermediate language patterns. In one embodiment of the invention, a pattern matcher generation method can be provided. The method can include identifying input elements from intermediate language code, reducing the identified input elements from the intermediate language code to inputs of common and unique use, creating a unifiable form for each of the input elements of common and unique use, and generating a pattern matcher for each of the input elements of common and unique use in the intermediate language code using a corresponding unifiable form in place of each of the input elements of common and unique use. In particular, the generated pattern matcher can be expression matching and transformation programming framework (EMTF) conformant.

Abstract: Under the present invention, program code is examined (statically or dynamically) for characteristics indicative of a potential to generate multiple threads. If none are found, single threaded optimization(s) such as desynchronization, optimization of globals, etc., can be implemented. In addition, if the program code is later revealed to have the potential to generate multiple threads, the single threaded optimization(s) can be corrected to avoid incorrect execution.

Abstract: A method for combined static and dynamic compilation of program code to remove delinquent loads can include statically compiling source code into executable code with instrumented sections each being suspected of including a delinquent load, and also into a separate intermediate language representation with annotated portions each corresponding to one of the instrumented sections. The method also can include executing the instrumented sections repeatedly and monitoring cache misses for each execution. Finally, the method can include dynamically recompiling selected ones of the instrumented sections using corresponding ones of the annotated portions of the separate intermediate language representation only after a threshold number of executions of the selected ones of the instrumented sections, each recompilation include a pre-fetch directive at a pre-fetch distances tuned to avoid the delinquent load.

Abstract: A system for translating software in a first format into a second format includes a memory containing the software in the first format and an emulator coupled to the memory configured to translate the software from the first format to the second format. The system also includes a host engine coupled to the emulator and configured to perform instructions in the second format. The emulator is configured to determine whether a store command in the first format stores information to a memory page that includes instructions and to convert the store instruction to a special store instruction in the event that the target of the store instruction does not contain an instruction.

Abstract: A computer-implemented method, computer program product and data processing system to improve runtime performance of executable program code when executed on the data-processing system. During execution, data is collected and analyzed to identify runtime behavior of the program code. Heuristic models are applied to select region(s) of the program code where application of a performance improvement algorithm is expected to improve runtime performance. Each selected region is recompiled using selected performance improvement algorithm(s) for that region to generate corresponding recompiled region(s), and the program code is modified to replace invocations of each selected region with invocations of the corresponding recompiled region. Alternatively or additionally, the program code may be recompiled to be adapted to characteristics of the execution environment of the data processing system.

Abstract: Optimizations are programmatically applied by a compiler (preferably, a just-in-time or “JIT” compiler), and enable achieving improved performance while a variable acts as a global constant, yet also allow code to execute correctly if the global constant's run-time value changes from the value on which the optimization was originally based. Code snippets that dynamically patch executable code are described, where these code snippets take corrective actions to enable correct program execution following a run-time change to the value of a glacial constant. A backup recovery path may also be maintained, where this path provides code that is executed in the event of a change to a glacial constant and that treats the glacial constant as a variable. Recompilation may also be used after a change to a glacial constant, where the originally-compiled code has made an assumption about the glacial constant's value that is no longer accurate. Combinations of these approaches may be used.

Abstract: A system for translating software in a first format into a second format includes a memory containing the software in the first format and an emulator coupled to the memory configured to translate the software from the first format to the second format. The system also includes a host engine coupled to the emulator and configured to perform instructions in the second format. The emulator is configured to determine whether a store command in the first format stores information to a memory page that includes instructions and to convert the store instruction to a special store instruction in the event that the target of the store instruction does not contain an instruction.

Abstract: Under the present invention, a locking primitive associated with a shared data object is automatically transformed to allow multiple read-only locks if certain conditions are met. To this extent, when a read-only lock on a shared data object is desired, a thread identifier of an object header lock word (hereinafter “lock word”) associated with the shared data object is examined to determine if a read-write lock on the shared data object already exists. If not, then the thread identifier is set to a predetermined value indicative of read-only locks, and a thread count in the lock word is incremented. If another thread attempts a read-only lock, the thread identifier will be examined for the predetermined value. If it is present, the thread count will be incremented again, and a second read-only lock will be simultaneously established.

Abstract: A computer readable storage medium is provided having executable instructions stored thereon for executing a method of operating a computing system, in which an inner virtual machine translates first instructions, which are supported by the inner virtual machine, into second instructions, which are supported by an outer virtual machine. The method includes encoding, in the inner virtual machine, third instructions into the second instructions into which the first instructions are translated, the third instructions including hints for facilitating an execution of the second instructions, and, in an event the hints are supported by the outer virtual machine, initiating the execution of the second instructions while utilizing the hints by the outer virtual machine to achieve an increased efficiency of the execution of the second instructions.

Abstract: Optimizing a program having a plurality of functions. The program is optimized using an optimization technique that requires breaking a calling convention. The first function of the plurality of functions is modified as a result of optimizing. A name of the first function is mangled to form a unique first mangled name. Mangling comprises changing the name. The unique first mangled name includes, as a result of mangling, first information conveying at least in part how the first function was modified. A second function of the plurality of functions, being a caller of the first function, is also modified to correctly invoke first function using the unique first mangled name to apply the optimization technique. A compilation tool can, after optimizing, use the first information to take a first action with respect to the first procedure, wherein the compilation tool otherwise would require the calling convention to remain unbroken in order to take the first action.

Abstract: A method for combined static and dynamic compilation of program code to remove delinquent loads can include statically compiling source code into executable code with instrumented sections each being suspected of including a delinquent load, and also into a separate intermediate language representation with annotated portions each corresponding to one of the instrumented sections. The method also can include executing the instrumented sections repeatedly and monitoring cache misses for each execution. Finally, the method can include dynamically recompiling selected ones of the instrumented sections using corresponding ones of the annotated portions of the separate intermediate language representation only after a threshold number of executions of the selected ones of the instrumented sections, each recompilation include a pre-fetch directive at a pre-fetch distances tuned to avoid the delinquent load.

Abstract: Embodiments of the present invention address deficiencies of the art in respect to pattern matcher generation and provide a method, system and computer program product for automatic pattern matching and generation of intermediate language patterns. In one embodiment of the invention, a pattern matcher generation method can be provided. The method can include identifying input elements from intermediate language code, reducing the identified input elements from the intermediate language code to inputs of common and unique use, creating a unifiable form for each of the input elements of common and unique use, and generating a pattern matcher for each of the input elements of common and unique use in the intermediate language code using a corresponding unifiable form in place of each of the input elements of common and unique use. In particular, the generated pattern matcher can be EMTF conformant.

Abstract: Under the present invention, program code is examined (statically or dynamically) for characteristics indicative of a potential to generate multiple threads. If none are found, single threaded optimization(s) such as desynchronization, optimization of globals, etc., can be implemented. In addition, if the program code is later revealed to have the potential to generate multiple threads, the single threaded optimization(s) can be corrected to avoid incorrect execution.

Abstract: The problem of handling exceptionally executed code portions is improved through the practice of embedding handling instructions within other instructions, such as within their “immediate” fields. Such instructions are chosen to have short execution times. Most of the time these instructions are executed quickly without having to include jumps around them. Only rarely are the other portions of these specialized computer instruction needed or used.