Abstract: In a decode stage of hardware processor pipeline, one particular instruction of a plurality of instructions is decoded. It is determined that the particular instruction requires a memory access. Responsive to such determination, it is predicted whether the memory access will result in a cache miss. The predicting in turn includes accessing one of a plurality of entries in a pattern history table stored as a hardware table in the decode stage. The accessing is based, at least in part, upon at least a most recent entry in a global history buffer. The pattern history table stores a plurality of predictions. The global history buffer stores actual results of previous memory accesses as one of cache hits and cache misses.

Abstract: Examples of techniques for distance-based branch prediction are disclosed. In one example implementation according to aspects of the present disclosure, a computer-implemented method includes: determining, by a processing system, a potential return instruction address (IA) by determining whether a relationship is satisfied between a first target IA and a first branch IA; storing a second branch IA as a return when a target IA of a second branch matches a potential return IA for the second branch; and applying the potential return IA for the second branch as a predicted target IA of a predicted branch IA stored as a return.

Abstract: Embodiments are directed to a method for optimizing performance of a microprocessor. The method includes monitoring the performance of the microprocessor in each of a plurality of performance modes. The method further includes choosing a performance mode based on the monitoring. Thereafter, using the performance mode for a predetermined amount of time. Each of the plurality of performance modes is a branch prediction mode.

Abstract: Examples of techniques for constructing a spatial map of a physical space are disclosed. In one example implementation according to aspects of the present disclosure, a computer-implemented method includes collecting, by a processing device, signal strength data about a plurality of user devices as the plurality of user devices move throughout the physical space, the signal strength data being indicative of a signal strength of a wireless signal between at least one of the plurality of user devices and at least one of a plurality of access points associated with the physical space. The method further includes generating, by the processing device, a signal space map based at least in part on the signal strength data. The method further includes transforming, by the processing device, the signal space map of the physical space into the spatial map of the physical space to construct the spatial map of the physical space.

Abstract: A method includes a processor providing at least one line entry address tag in each line of a branch predictor; indexing into the branch predictor with a current line address to predict a taken branch's target address and a next line address; re-indexing into the branch predictor with one of a predicted next line address or a sequential next line address when the at least one line entry address tag does not match the current line address; using branch prediction content compared against a search address to predict a direction and targets of branches and determining when a new line address is generated; and re-indexing into the branch predictor with a corrected next line address when it is determined that one of the predicted next line address or the sequential next line address differs from the new line address.

Abstract: Embodiments are directed to a computer implemented method for executing machine instructions in a central processing unit. The method includes obtaining, by a processor system, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture. The method further includes executing the machine instruction, wherein the executing includes loading a multiplicand into a multiplicand register, and loading a multiplier into a multiplier register. The executing further generates an intermediate product having least significant bits by multiplying the multiplicand and the multiplier. The executing further includes generating a rounded product by performing a probability analysis on the least significant bits of the intermediate product, and initiating a rounding operation on the intermediate product to produce the rounded product based at least in part on the probability analysis.

Abstract: Embodiments relate to branch prediction using a pattern history table (PHT) that is indexed using a global path vector (GPV). An aspect includes receiving a search address by a branch prediction logic that is in communication with the PHT and the GPV. Another aspect includes starting with the search address, simultaneously determining a plurality of branch predictions by the branch prediction logic based on the PHT, wherein the plurality of branch predictions comprises one of: (i) at least one not taken prediction and a single taken prediction, and (ii) a plurality of not taken predictions. Another aspect includes updating the GPV by shifting an instruction identifier of a branch instruction associated with a taken prediction into the GPV, wherein the GPV is not updated based on any not taken prediction.

Abstract: A method for implementing a programmable linear feedback shift register instruction, the method includes obtaining, by a processor, the machine instruction for execution, the machine instruction includes a first input operand indicating the current value of a shift register, wherein the shift register includes a data bit for each of a plurality of cells, a second input operand indicating a first sub-set of cells from the plurality of cells, and a logical operation specifier field indicating a logical operation to perform on the first and second input operands. Additionally, executing the machine instruction includes performing the logical operation based on the first input operand, the second input operand, and the logical operation specifier field, and generating an output operand by shifting the current value of the shift register to vacate a cell of the shift register and inserting an output value of the logical operation into the vacated cell of the shift register.

Abstract: Examples of techniques for constructing a spatial map of a physical space are disclosed. In one example implementation according to aspects of the present disclosure, a computer-implemented method includes collecting, by a processing device, signal strength data about a plurality of user devices as the plurality of user devices move throughout the physical space, the signal strength data being indicative of a signal strength of a wireless signal between at least one of the plurality of user devices and at least one of a plurality of access points associated with the physical space. The method further includes generating, by the processing device, a signal space map based at least in part on the signal strength data. The method further includes transforming, by the processing device, the signal space map of the physical space into the spatial map of the physical space to construct the spatial map of the physical space.

Abstract: As disclosed herein a method, executed by a processor, for accelerated instruction execution includes retrieving an execute instruction including a register reference and a reference to a target instruction, retrieving the target instruction, decoding the execute instruction using an instruction pipeline, decoding the target instruction using the instruction pipeline, associating the register reference to the target instruction, and executing the target instruction using the register reference as a source operand modifier. The instruction pipeline is configured such that it allows the target instruction to continue processing without waiting for the register reference to be resolved. The contents of the referenced register may be retrieved in a later stage of the instruction pipeline, and the target instruction may be modified and executed. An apparatus corresponding to the described method is also disclosed herein.

Abstract: Embodiments relate to branch prediction using a pattern history table (PHT) that is indexed using a global path vector (GPV). An aspect includes receiving a search address by a branch prediction logic that is in communication with the PHT and the GPV. Another aspect includes starting with the search address, simultaneously determining a plurality of branch predictions by the branch prediction logic based on the PHT, wherein the plurality of branch predictions comprises one of: (i) at least one not taken prediction and a single taken prediction, and (ii) a plurality of not taken predictions. Another aspect includes updating the GPV by shifting an instruction identifier of a branch instruction associated with a taken prediction into the GPV, wherein the GPV is not updated based on any not taken prediction.

Abstract: Embodiments are directed to a computer implemented method for executing machine instructions in a central processing unit. The executing includes loading a first operand into a first operand register, and loading a second operand into a second operand register. The executing further includes shifting either the first operand or the second operand to form a shifted operand. The executing further includes adding or subtracting the first operand and the second operand to obtain a sum or a difference, and loading the sum or the difference having a least significant bit into a third register or a memory. The executing further includes performing a probability analysis on least significant bits of the shifted operand or the non-shifted operand, and initiating a rounding operation on the least significant bit of the sum or the difference based at least in part on the probability analysis.

Abstract: Resources in a computing environment are managed, for example, by a hardware controller controlling dispatching of resources from one or more pools of resources to be used in execution of threads. The controlling includes conditionally dispatching resources from the pool(s) to one or more low-priority threads of the computing environment based on current usage of resources in the pool(s) relative to an associated resource usage threshold. The management further includes monitoring resource dispatching from the pool(s) to one or more high-priority threads of the computing environment, and based on the monitoring, dynamically adjusting the resource usage threshold used in the conditionally dispatching of resources from the pool(s) to the low-priority thread(s).

Abstract: Embodiments are directed to a computer implemented method for executing machine instructions in a central processing unit. The executing includes loading a first operand into a first operand register, and loading a second operand into a second operand register. The executing further includes shifting either the first operand or the second operand to form a shifted operand. The executing further includes adding or subtracting the first operand and the second operand to obtain a sum or a difference, and loading the sum or the difference having a least significant bit into a third register or a memory. The executing further includes performing a probability analysis on least significant bits of the shifted operand or the non-shifted operand, and initiating a rounding operation on the least significant bit of the sum or the difference based at least in part on the probability analysis.

Abstract: Embodiments include method, systems and computer program products for variable branch target buffer line size for compression. In some embodiments, a branch target buffer (BTB) congruence class for a line of a first parent array of a BTB may be determined. A threshold indicative of a maximum number branches to be stored in the line may be set. A branch may be received to store in the line of the first parent array. A determination may be made that storing the branch in the line would exceed the threshold and the line can be responsively split into an even half line and an odd half line.

Abstract: Embodiments are directed to a computer implemented method for executing machine instructions in a central processing unit. The method includes obtaining, by a processor system, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture. The method further includes executing the machine instruction, wherein the executing includes loading a multiplicand into a multiplicand register, and loading a multiplier into a multiplier register. The executing further generates an intermediate product having least significant bits by multiplying the multiplicand and the multiplier. The executing further includes generating a rounded product by performing a probability analysis on the least significant bits of the intermediate product, and initiating a rounding operation on the intermediate product to produce the rounded product based at least in part on the probability analysis.

Abstract: A method, system, and computer program product of utilizing branch prediction logic in a system that processes instructions that include a branch are described. The method includes identifying the branch as conventionally predictable or not conventionally predictable, and based on the branch being identified as not conventionally predictable according to the identifying, either foregoing branch prediction and reallocating, using a processor, the branch prediction logic to another thread of the instructions or performing, using the processor, the branch prediction and speculative execution of one or more of the instructions following the branch to obtain prediction information. Based on the performing the branch prediction and the speculative execution, the method also includes verifying a match between a branch end according to the instructions and a branch end according to the branch prediction prior to providing the prediction information to a second processor processing the instructions.

Abstract: Embodiments include a technique for caching of perceptron branch patterns using ternary content addressable memory. The technique includes defining a table of perceptrons, each perceptron having a plurality of weights with each weight being associated with a bit location in a history vector, and defining a TCAM, the TCAM having a number of entries, wherein each entry includes a number of bit pairs, the number of bit pairs being equal to a number of weights for each associated perceptron. The technique also includes associating the TCAM with an array of x-bit saturating counters, and performing a branch prediction for a history vector of a given branch, the branch prediction indicating a perceptron prediction. The technique includes determining a most influential bit location in the history vector, the most influential bit location having a greatest weight of an associated perceptron.

Abstract: A method for branch prediction, the method comprising, receiving a branch wrong guess instruction having a branch wrong guess instruction address and data including an opcode and a branch target address, determining whether the branch wrong guess instruction was predicted by a branch prediction mechanism, sending the branch wrong guess instruction to an execution unit responsive to determining that the branch wrong guess instruction was predicted by the branch prediction mechanism, and receiving and decoding instructions at the branch target address.

Abstract: A method for implementing a programmable linear feedback shift register instruction, the method includes obtaining, by a processor, the machine instruction for execution, the machine instruction includes a first input operand indicating the current value of a shift register, wherein the shift register includes a data bit for each of a plurality of cells, a second input operand indicating a first sub-set of cells from the plurality of cells, and a logical operation specifier field indicating a logical operation to perform on the first and second input operands. Additionally, executing the machine instruction includes performing the logical operation based on the first input operand, the second input operand, and the logical operation specifier field, and generating an output operand by shifting the current value of the shift register to vacate a cell of the shift register and inserting an output value of the logical operation into the vacated cell of the shift register.