Abstract: Aspects of the invention include defining one or more processor units having a plurality of caches, each processor unit comprising a processor having at least one cache, and wherein each of the one or more processor units are coupled together by an interconnect fabric, for each of the plurality of caches, arranging a plurality of cache lines into one or more congruence classes, each congruence class comprises a chronology vector, arranging each cache in the plurality of caches into a cluster of caches based on a plurality of scope domains, determining a first cache line to evict based on the chronology vector, and determining a target cache for installing the first cache line based on a scope of the first cache line and a saturation metric associated with the target cache, wherein the scope of the first cache line is determined based on lateral persistence tag bits.

Abstract: Aspects of the invention include computer-implemented methods, systems, and computer program products that access a multi-copy scope directory state of a cache memory that indicates a scope of sharing of a cache line in a cache memory system and determine a scope of sharing of the cache line in the cache memory system based on the multi-copy scope directory state, where the multi-copy scope directory state enumerates a plurality of scopes within the cache memory system. The scope of sharing is used to reduce a number of queries to one or more cache memories having a larger scope than a shared scope identified in the scope of sharing. The multi-copy scope directory state of the cache memory is updated based on detecting a change in shared scope of the cache line within the cache memory system.

Abstract: A method of performing instruction scheduling during execution in a processor includes receiving, at an execution unit of the processor, an initial assignment of an assigned execution resource among two or more execution resources to execute an operation. An instruction includes two or more operations. Based on determining that the assigned execution resource is not available, the method also includes determining, at the execution unit, whether another execution resource among the two or more execution resources is available to execute the operation. Based on determining that the other execution resource is available, the method further includes executing the operation with the other execution resource.

Abstract: A computer-implemented method for detecting vulnerabilities in microarchitectures. A non-limiting example of the computer-implemented method includes creating a simulation for execution on a model of a microarchitecture, the simulation including a set of instructions and a placeholder for holding a piece of secret data. The computer-implemented method executes the simulation a first time on the model of the microarchitecture with a first piece of secret data stored in the placeholder and stores a first output of the first executed simulation. The computer-implemented method executes the simulation a second time on the model of the microarchitecture with a second piece of secret data stored in the placeholder and stores a second output of the second executed simulation. The computer-implemented method compares the first output with the second output and provides an indication of a microarchitecture vulnerability when there is a difference between the first output and the second output.

Abstract: A computer data processing system includes an instruction pipeline having a front end and a back end, a decoding and dispatch unit to dispatch a current instruction; and a pipeline by-pass unit to invoke an out-of-order pipeline by-pass operation. The pipeline by-pass unit by-passes a section of the instruction pipeline such that the current instruction architecturally completes before initiating instruction execution. The computer data processing system further includes a post-completion execution unit that executes the current instruction after the current instruction architecturally completes.

Abstract: Methods and systems for controlling writing to register files in a processing system having at least two execution pipelines are provided. Aspects include obtaining a micro operation for execution by an execution unit of a first pipeline in the processing system, wherein the micro operation includes writing data to a register file. Aspects also include determining whether the data will be accessed by an execution unit of a second pipeline in the processing system. Based on a determination that the data will only be accessed by the execution unit of the first pipeline, aspects include blocking writing of the data to a register file of the second pipeline.

Abstract: Examples of techniques for store hit multiple load side register for operand store compare are described herein. An aspect includes, based on detecting a store hit multiple load condition in the processor, updating a register of the processor to hold information corresponding to a first store instruction that triggered the detected store hit multiple load condition. Another aspect includes, based on issuing a second store instruction in the processor, determining whether the second store instruction corresponds to the information in the register. Another aspect includes, based on determining that the second store instruction corresponds to the information in the register, tagging the second store instruction with an operand store compare mark.

Abstract: A computer implemented method for marking a store instruction overlap in a processor pipeline is provided. A non-limiting example of the method includes detecting a second store instruction subsequent to a first store instruction in an instruction stream, in which there is a match between the operand address information of the first store instruction and a load instruction. The operand address information of the first store instruction is compared with the operand address information of the second store instruction to determine whether there is match. In the event of a match, the second store instruction is delayed in the processor pipeline in response to determining that there is a memory image overlap between the operand address information of the second store instruction and the first store instruction.

Abstract: A computer-implemented method is provided and includes allocating, by a processor, an instruction to a first thread, decoding, by the processor, the instruction, determining, by the processor, a type of the instruction based on information obtained by decoding the instruction, and based on determining that the instruction is a disruptive complex instruction, changing a mode of allocating hardware resources to an instruction-based allocation mode. In the instruction-based allocation mode, the processor adjusts allocation of the hardware resources among a first thread and a second thread based on types of instructions allocated to the first and second threads.

Abstract: A computer data processing system includes an instruction pipeline having a front end and a back end, a decoding and dispatch unit to dispatch a current instruction; and a pipeline by-pass unit to invoke an out-of-order pipeline by-pass operation. The pipeline by-pass unit by-passes a section of the instruction pipeline such that the current instruction architecturally completes before initiating instruction execution. The computer data processing system further includes a post-completion execution unit that executes the current instruction after the current instruction architecturally completes.

Abstract: A method includes allocating a first entry in a global completion table (GCT) on a processor, responsive to a first instruction group being dispatched, where the first entry corresponds to the first instruction group. A data value applicable to the first instruction group is identified. An offset value applicable to the first instruction group is calculated by subtracting, from the data value, a base value previously written to a second entry of the GCT for a second instruction group. The offset value is written in the first entry of the GCT in lieu of the data value.

Abstract: Implementing processor instrumentation in a processor pipeline includes determining a pipeline depth of each micro-operator for an instruction group used in an execution phase of the processor pipeline. The pipeline depth corresponds with a duration of execution, each micro-operator performs a type of functional operation in the execution phase, and the instruction group includes all the micro-operators required for the execution phase. A targeted micro-operator is identified for which the processor instrumentation is being performed, and the pipeline depth corresponding with the targeted micro-operator is used to determine and report a performance of the targeted micro-operator as part of the processor instrumentation. Problems indicated by the processor instrumentation are diagnosed and addressed based on the performance of the targeted micro-operator.

Abstract: A computer-implemented method for detecting vulnerabilities in microarchitectures. A non-limiting example of the computer-implemented method includes creating a simulation for execution on a model of a microarchitecture, the simulation including a set of instructions and a placeholder for holding a piece of secret data. The computer-implemented method executes the simulation a first time on the model of the microarchitecture with a first piece of secret data stored in the placeholder and stores a first output of the first executed simulation. The computer-implemented method executes the simulation a second time on the model of the microarchitecture with a second piece of secret data stored in the placeholder and stores a second output of the second executed simulation. The computer-implemented method compares the first output with the second output and provides an indication of a microarchitecture vulnerability when there is a difference between the first output and the second output.

Abstract: A computer data processing system includes an instruction pipeline having a front end and a back end, a decoding and dispatch unit to dispatch a current instruction; and a pipeline by-pass unit to invoke an out-of-order pipeline by-pass operation. The pipeline by-pass unit by-passes a section of the instruction pipeline such that the current instruction architecturally completes before initiating instruction execution. The computer data processing system further includes a post-completion execution unit that executes the current instruction after the current instruction architecturally completes.

Abstract: Provided are embodiments including a computer-implemented method, system and computer program product for determining precise operand-store-compare (OSC) predictions to avoid false dependencies. Some embodiments include detecting an instruction causing an OSC event, wherein the OSC event is at least one of a store-hit-load event or a load-hit-store event, marking an entry in a queue for the instruction based on the detected OSC event, wherein marking the entry comprises setting a bit and saving a tag in the entry in the queue. Some embodiments also include installing an address for the instruction and the tag in the history table responsive to completing the instruction.

Abstract: Implementing processor instrumentation in a processor pipeline includes determining a pipeline depth of each micro-operator for an instruction group used in an execution phase of the processor pipeline. The pipeline depth corresponds with a duration of execution, each micro-operator performs a type of functional operation in the execution phase, and the instruction group includes all the micro-operators required for the execution phase. A targeted micro-operator is identified for which the processor instrumentation is being performed, and the pipeline depth corresponding with the targeted micro-operator is used to determine and report a performance of the targeted micro-operator as part of the processor instrumentation. Problems indicated by the processor instrumentation are diagnosed and addressed based on the performance of the targeted micro-operator.

Abstract: A method of performing instruction scheduling during execution in a processor includes receiving, at an execution unit of the processor, an initial assignment of an assigned execution resource among two or more execution resources to execute an operation. An instruction includes two or more operations. Based on determining that the assigned execution resource is not available, the method also includes determining, at the execution unit, whether another execution resource among the two or more execution resources is available to execute the operation. Based on determining that the other execution resource is available, the method further includes executing the operation with the other execution resource.

Abstract: A computer data processing system includes a plurality of logical registers, each including multiple storage sections. A processor writes data a storage section based on a dispatched first instruction, and sets a valid bit corresponding to the storage section that receives the data. In response to each subsequent instruction, the processor sets an evictor valid bit indicating a subsequent instruction has written new data to a storage section written by the first instruction, and updates the valid bit to indicate the storage section containing the new written data. A register combination unit generates a combined evictor tag to identify a most recent subsequent instruction. The processor determines the most recent subsequent instruction based on the combined evictor tag in response to a flush event, and unsets all the evictor tag valid bits set by the most the most recent subsequent instruction along with all previous subsequent instructions.

Abstract: Provided are embodiments including a computer-implemented method, system and computer program product for determining precise operand-store-compare (OSC) predictions to avoid false dependencies. Some embodiments include detecting an instruction causing an OSC event, wherein the OSC event is at least one of a store-hit-load event or a load-hit-store event, marking an entry in a queue for the instruction based on the detected OSC event, wherein marking the entry comprises setting a bit and saving a tag in the entry in the queue. Some embodiments also include installing an address for the instruction and the tag in the history table responsive to completing the instruction.

Abstract: A computer implemented method for marking a store instruction overlap in a processor pipeline is provided. A non-limiting example of the method includes detecting a second store instruction subsequent to a first store instruction in an instruction stream, in which there is a match between the operand address information of the first store instruction and a load instruction. The operand address information of the first store instruction is compared with the operand address information of the second store instruction to determine whether there is match. In the event of a match, the second store instruction is delayed in the processor pipeline in response to determining that there is a memory image overlap between the operand address information of the second store instruction and the first store instruction.