Abstract: Embodiments include methods, computing systems and computer program products for identifying and tracking frequently accessed registers in a processor of a computing system. Aspects include: creating a list of top accessed registers of certain registers in processor, each register having a corresponding register usage counter, initializing each register usage counter, starting a register usage monitoring mode, examining each register usage counter, and updating list of top accessed registers, stopping register usage monitoring mode, and updating a register file partition assignment when the list of top accessed registers is identified. Once the list of top accessed registers is identified, stopping the programs and bring its threads of execution to quiescent, moving registers between register file partitions until all registers on the list of top accessed registers are in the fully-ported register file partition, and resuming executions of the program and its threads.

Abstract: There are provided a system, a method and a computer program product for selecting an active data stream (a lane) while running Single Program Multiple Data code on a Single Instruction Multiple Data machine. The machine runs an instruction stream over input data streams and machine increments lane depth counters of all active lanes upon the thread-PC reaching a branch operation and updates the lane-PC of each active lane according to targets of the branch operation. An instruction of the instruction stream includes a barrier indicating a convergence point for all lanes to join. In response to a lane reaching a barrier: evaluating whether all lane-PCs are set to a same thread-PC; and if the lane-PCs are not set to the same thread-PC, selecting an active lane from the plurality of lanes; otherwise, incrementing the lane-PCs of all the lanes, and then selecting an active lane from the plurality of lanes.

Abstract: Embodiments include methods, computing systems and computer program products for identifying and tracking frequently accessed registers in a processor of a computing system. Aspects include: creating a list of top accessed registers of certain registers in processor, each register having a corresponding register usage counter, initializing each register usage counter, starting a register usage monitoring mode, examining each register usage counter, and updating list of top accessed registers, stopping register usage monitoring mode, and updating a register file partition assignment when the list of top accessed registers is identified. Once the list of top accessed registers is identified, stopping the programs and bring its threads of execution to quiescent, moving registers between register file partitions until all registers on the list of top accessed registers are in the fully-ported register file partition, and resuming executions of the program and its threads.

Abstract: There are provided a system, a method and a computer program product for selecting an active data stream (a lane) while running Single Program Multiple Data code on a Single Instruction Multiple Data machine. The machine runs an instruction stream over input data streams and machine increments lane depth counters of all active lanes upon the thread-PC reaching a branch operation and updates the lane-PC of each active lane according to targets of the branch operation. An instruction of the instruction stream includes a barrier indicating a convergence point for all lanes to join. In response to a lane reaching a barrier: evaluating whether all lane-PCs are set to a same thread-PC; and if the lane-PCs are not set to the same thread-PC, selecting an active lane from the plurality of lanes; otherwise, incrementing the lane-PCs of all the lanes, and then selecting an active lane from the plurality of lanes.

Abstract: There are provided a system, a method and a computer program product for selecting an active data stream (a lane) while running SPMD (Single Program Multiple Data) code on SIMD (Single Instruction Multiple Data) machine. The machine runs an instruction stream over input data streams. The machine increments lane depth counters of all active lanes upon the thread-PC reaching a branch operation. The machine updates the lane-PC of each active lane according to targets of the branch operation. The machine selects an active lane and activates only lanes whose lane-PCs match the thread-PC. The machine decrements the lane depth counters of the selected active lanes and updates the lane-PC of each active lane upon the instruction stream reaching a first instruction. The machine assigns the lane-PC of a lane with a largest lane depth counter value to the thread-PC and activates all lanes whose lane-PCs match the thread-PC.

Abstract: There are provided a system, a method and a computer program product for selecting an active data stream (a lane) while running SPMD (Single Program Multiple Data) code on SIMD (Single Instruction Multiple Data) machine. The machine runs an instruction stream over input data streams. The machine increments lane depth counters of all active lanes upon the thread-PC reaching a branch operation. The machine updates the lane-PC of each active lane according to targets of the branch operation. The machine selects an active lane and activates only lanes whose lane-PCs match the thread-PC. The machine decrements the lane depth counters of the selected active lanes and updates the lane-PC of each active lane upon the instruction stream reaching a first instruction. The machine assigns the lane-PC of a lane with a largest lane depth counter value to the thread-PC and activates all lanes whose lane-PCs match the thread-PC.

Abstract: Embodiments include methods, computing systems and computer program products for identifying and tracking frequently accessed registers in a processor of a computing system. Aspects include: creating a list of top accessed registers of certain registers in processor, each register having a corresponding register usage counter, initializing each register usage counter, starting a register usage monitoring mode, examining each register usage counter, and updating list of top accessed registers, stopping register usage monitoring mode, and updating a register file partition assignment when the list of top accessed registers is identified. Once the list of top accessed registers is identified, stopping the programs and bring its threads of execution to quiescent, moving registers between register file partitions until all registers on the list of top accessed registers are in the fully-ported register file partition, and resuming executions of the program and its threads.

Abstract: There are provided a system, a method and a computer program product for selecting an active data stream (a lane) while running SPMD (Single Program Multiple Data) code on SIMD (Single Instruction Multiple Data) machine. The machine runs an instruction stream over input data streams. The machine increments lane depth counters of all active lanes upon the thread-PC reaching a branch operation. The machine updates the lane-PC of each active lane according to targets of the branch operation. The machine selects an active lane and activates only lanes whose lane-PCs match the thread-PC. The machine decrements the lane depth counters of the selected active lanes and updates the lane-PC of each active lane upon the instruction stream reaching a first instruction. The machine assigns the lane-PC of a lane with a largest lane depth counter value to the thread-PC and activates all lanes whose lane-PCs match the thread-PC.

Abstract: Embodiments include methods, computing systems and computer program products for identifying and tracking frequently accessed registers in a processor of a computing system. Aspects include: creating a list of top accessed registers of certain registers in processor, each register having a corresponding register usage counter, initializing each register usage counter, starting a register usage monitoring mode, examining each register usage counter, and updating list of top accessed registers, stopping register usage monitoring mode, and updating a register file partition assignment when the list of top accessed registers is identified. Once the list of top accessed registers is identified, stopping the programs and bring its threads of execution to quiescent, moving registers between register file partitions until all registers on the list of top accessed registers are in the fully-ported register file partition, and resuming executions of the program and its threads.

Abstract: Techniques for increasing vector processing utilization and efficiency through use of unmasked lanes of predicated vector instructions for executing non-conflicting instructions are provided. In one aspect, a method of vector lane predication for a processor is provided which includes the steps of: fetching predicated vector instructions from a memory; decoding the predicated vector instructions; determining if a mask value of the predicated vector instructions is available and, if the mask value of the predicated vector instructions is not available, predicting the mask value of the predicated vector instructions; and dispatching the predicated vector instructions to only masked vector lanes.

Abstract: Techniques for switching between two (thread and lane) modes of execution in a dual execution mode processor are provided. In one aspect, a method for executing a single instruction stream having alternating serial regions and parallel regions in a same processor is provided. The method includes the steps of: creating a processor architecture having, for each architected thread of the single instruction stream, one set of thread registers, and N sets of lane registers across N lanes; executing instructions in the serial regions of the single instruction stream in a thread mode against the thread registers; executing instructions in the parallel regions of the single instruction stream in a lane mode against the lane registers; and transitioning execution of the single instruction stream from the thread mode to the lane mode or from the lane mode to the thread mode.

Abstract: Techniques for switching between two (thread and lane) modes of execution in a dual execution mode processor are provided. In one aspect, a method for executing a single instruction stream having alternating serial regions and parallel regions in a same processor is provided. The method includes the steps of: creating a processor architecture having, for each architected thread of the single instruction stream, one set of thread registers, and N sets of lane registers across N lanes; executing instructions in the serial regions of the single instruction stream in a thread mode against the thread registers; executing instructions in the parallel regions of the single instruction stream in a lane mode against the lane registers; and transitioning execution of the single instruction stream from the thread mode to the lane mode or from the lane mode to the thread mode.

Abstract: There are provided a system, a method and a computer program product for selecting an active data stream (a lane) while running SPMD (Single Program Multiple Data) code on SIMD (Single Instruction Multiple Data) machine. The machine runs an instruction stream over input data streams. The machine increments lane depth counters of all active lanes upon the thread-PC reaching a branch operation. The machine updates the lane-PC of each active lane according to targets of the branch operation. The machine selects an active lane and activates only lanes whose lane-PCs match the thread-PC. The machine decrements the lane depth counters of the selected active lanes and updates the lane-PC of each active lane upon the instruction stream reaching a first instruction. The machine assigns the lane-PC of a lane with a largest lane depth counter value to the thread-PC and activates all lanes whose lane-PCs match the thread-PC.

Abstract: Techniques for increasing vector processing utilization and efficiency through use of unmasked lanes of predicated vector instructions for executing non-conflicting instructions are provided. In one aspect, a method of vector lane predication for a processor is provided which includes the steps of: fetching predicated vector instructions from a memory; decoding the predicated vector instructions; determining if a mask value of the predicated vector instructions is available and, if the mask value of the predicated vector instructions is not available, predicting the mask value of the predicated vector instructions; and dispatching the predicated vector instructions to only masked vector lanes.

Abstract: Aspects of the present invention provide a solution for maximizing server site resources in a server network. In an embodiment, an application signature is collected for an application. This application signature includes a representation of operating characteristics of the application. The application signature is compared with application signatures collected from other applications in the server network. Based on the comparison, the application is assigned for execution to a server site that hosts a group of applications that have similar application signatures to that of the application.

Abstract: Aspects of the present invention provide a solution for maximizing server site resources in a server network. In an embodiment, an application signature is collected for an application. This application signature includes a representation of operating characteristics of the application. The application signature is compared with application signatures collected from other applications in the server network. Based on the comparison, the application is assigned for execution to a server site that hosts a group of applications that have similar application signatures to that of the application.