Abstract: A processor includes a counter to store a cycle count that tracks a number of cycles between retirement of a first branch instruction and retirement of a second branch instruction during execution of a set of instructions. The processor further includes a stack of registers coupled to the counter, wherein the stack of registers is to store branch type information including: a first value of the counter when the first branch instruction is retired; a second value of the counter when the second branch instruction is retired; a first type information value indicating a type of the first branch instruction; and a second type information value indicating a type of the second branch instruction.

Abstract: A processor includes a counter to store a cycle count that tracks a number of cycles between retirement of a first branch instruction and retirement of a second branch instruction during execution of a set of instructions. The processor further includes a stack of registers coupled to the counter, wherein the stack of registers is to store branch type information including: a first value of the counter when the first branch instruction is retired; a second value of the counter when the second branch instruction is retired; a first type information value indicating a type of the first branch instruction; and a second type information value indicating a type of the second branch instruction.

Abstract: An example processor that includes a decoder, an execution circuit, a counter, and a last branch recorder (LBR) register. The decoder may decode a branch instruction for a program. The execution circuit may be coupled to the decoder, where the execution circuit may execute the branch instruction. The counter may be coupled to the execution circuit, where the counter may store a cycle count. The LBR register coupled to the execution circuit, where the LBR register may include a counter field to store a first value of the counter when the branch instruction is executed and a type field to store type information indicating a type of the branch instruction.

Abstract: Embodiments of an invention for a physical register table for eliminating move instructions are disclosed. In one embodiment, a processor includes a physical register file, a register allocation table, and a physical register table. The register allocation table is to store mappings of logical registers to physical registers. The physical register table is to store entries including pointers to physical registers in the mappings. The number of entry locations in the physical register table is less than the number of physical registers in the physical register file.

Abstract: Embodiments disclosed herein provide for monitoring performance of a processing device to manage non-precise events. A processing device includes a performance counter to track a non-precise event and to increment upon occurrence of the non-precise event, wherein the non-precise event comprises a first type of performance event that is not linked to an instruction in an instruction trace. The processing device also includes a first handler circuit to generate and store a first record, the first record comprising architectural metadata defining a state of the processing device at a time of generation of the first record, wherein the first handler circuit to generate records corresponding to precise events. The processing device further includes a second handler circuit communicably coupled to the first handler circuit, the second handler circuit to cause the first handler circuit to generate a second record for the non-precise event upon overflow of the performance counter.

Abstract: A processor includes a back end to execute decoded instructions and a front end. The front end includes two decode clusters and circuitry to receive data elements representing undecoded instructions, in program order, and to direct subsets of the data elements to the decode clusters. An IP generator directs one subset of data elements to the first cluster, detects a condition indicating that a load balancing action should be taken, and directs a subset of data elements immediately following the first subset in program order to the first or second decode cluster dependent on the action taken. The action may include annotating a BTB entry, inserting a fake branch in the BTB, forcing a cluster switch, or suppressing a cluster switch. The detected condition may be a predicated taken branch or an annotation thereof, or a heuristic based on a queue state, a count of uops, or a latency value.

Abstract: Apparatuses, methods, and systems relating to memory disambiguation are described. In one embodiment, a processor includes a decoder to decode an instruction into a decoded instruction, an execution unit to execute the decoded instruction, a retirement unit to retire an executed instruction in program order, and a memory disambiguation circuit to allocate an entry in a memory disambiguation table for a first load instruction that is to be flushed for a memory ordering violation, the entry comprising a counter value and an instruction pointer for the first load instruction.

Abstract: An example processor that includes a decoder, an execution circuit, a counter, and a last branch recorder (LBR) register. The decoder may decode a branch instruction for a program. The execution circuit may be coupled to the decoder, where the execution circuit may execute the branch instruction. The counter may be coupled to the execution circuit, where the counter may store a cycle count. The LBR register coupled to the execution circuit, where the LBR register may include a counter field to store a first value of the counter when the branch instruction is executed and a type field to store type information indicating a type of the branch instruction.

Abstract: A processor includes a back end to execute decoded instructions and a front end. The front end includes two decode clusters and circuitry to receive data elements representing undecoded instructions, in program order, and to direct subsets of the data elements to the decode clusters. An IP generator directs one subset of data elements to the first cluster, detects a condition indicating that a load balancing action should be taken, and directs a subset of data elements immediately following the first subset in program order to the first or second decode cluster dependent on the action taken. The action may include annotating a BTB entry, inserting a fake branch in the BTB, forcing a cluster switch, or suppressing a cluster switch. The detected condition may be a predicated taken branch or an annotation thereof, or a heuristic based on a queue state, a count of uops, or a latency value.

Abstract: Apparatuses, methods, and systems relating to memory disambiguation are described. In one embodiment, a processor includes a decoder to decode an instruction into a decoded instruction, an execution unit to execute the decoded instruction, a retirement unit to retire an executed instruction in program order, and a memory disambiguation circuit to allocate an entry in a memory disambiguation table for a first load instruction that is to be flushed for a memory ordering violation, the entry comprising a counter value and an instruction pointer for the first load instruction.

Abstract: Embodiments disclosed herein provide for monitoring performance of a processing device to manage non-precise events. A processing device includes a performance counter to track a non-precise event and to increment upon occurrence of the non-precise event, wherein the non-precise event comprises a first type of performance event that is not linked to an instruction in an instruction trace. The processing device also includes a first handler circuit to generate and store a first record, the first record comprising architectural metadata defining a state of the processing device at a time of generation of the first record, wherein the first handler circuit to generate records corresponding to precise events. The processing device further includes a second handler circuit communicably coupled to the first handler circuit, the second handler circuit to cause the first handler circuit to generate a second record for the non-precise event upon overflow of the performance counter.

Abstract: A processor includes a core to execute decoded instructions and a front end. The front end includes two decode clusters and circuitry to receive data elements representing undecoded instructions, in program order, and to direct different subsets of the data elements to the two decode clusters. A splitter begins directing data elements to the first decode cluster, detects a cluster switching trigger condition, and directs a second subset of the data elements that immediately follows the first subset of data elements in program order to the second decode cluster. The trigger condition may be a predicated taken branch. The front end also includes circuitry to merge the decoded instructions generated by the first decode cluster and the decoded instructions generated by the second decode cluster to generate a sequence of decoded instructions in program order, based on a toggle indicator, and to provide it to the core for execution.

Abstract: In one embodiment, a processor includes an instruction decoder to receive and decode an instruction having a prefix and an opcode, an execution unit to execute the instruction based on the opcode, and flag modification override logic to prevent the execution unit from modifying a flag register of the processor based on the prefix of the instruction.

Abstract: In one embodiment, a processor includes an instruction decoder to receive a first instruction having a prefix and an opcode and to generate, by an instruction decoder of the processor, a second instruction executable based on a condition determined based on the prefix, and an execution unit to conditionally execute the second instruction based on the condition determined based on the prefix.

Abstract: In accordance with embodiments disclosed herein, there is provided systems and methods for monitoring performance of a processing device to manage non-precise events. A processing device includes a performance counter to increment upon occurrence of a non-precise event in the processing device. The processing device also includes a precise event based sampling (PEBS) enable control communicably coupled to the performance counter. The processing device also includes a PEBS handler to generate and store a PEBS record including an architectural metadata defining a state of the processing device at a time of generation of the PEBS record. The processing device further includes a non-precise event based sampling (NPEBS) module communicably coupled to the PEBS control and the PEBS handler. The NPEBS module causes the PEBS handler to generate the PEBS record for the non-precise event upon overflow of the performance counter.

Abstract: In some implementations, a processor may include a data structure, such as a translation lookaside buffer, that includes an entry containing first mapping information having a virtual address and a first context associated with a first thread. Control logic may receive a request for second mapping information having the virtual address and a second context associated with a second thread. The control logic may determine whether the second mapping information associated with the second context is equivalent to the first mapping information in the entry of the data structure. If the second mapping information is equivalent to the first mapping information, the control logic may associate the second thread with the first mapping information contained in the entry of the data structure to share the entry between the first thread and the second thread.

Abstract: A processor and method are described for implementing performance monitoring using a fixed function performance counter. For example, one embodiment of an apparatus comprises: a fixed function performance counter to decrement or increment upon occurrence of an event in the processing device; a precise event based sampling (PEBS) enable control communicably coupled to the fixed function performance counter; a PEBS handler to generate and store a PEBS record comprising architectural metadata defining a state of the processing device at a time of generation of the PEBS record; and a non-precise event based sampling (NPEBS) module communicably coupled to the PEBS enable control and the PEBS handler, the NPEBS module to cause the PEBS handler to generate the PEBS record for the event upon the fixed function performance counter reaching a specified value.

Abstract: A processor includes a microcode storage comprising a plurality of microcode flows and a decode logic coupled to the microcode storage. The decode logic is configured to receive a first instruction, decode the first instruction into an entry point vector to a first microcode flow in the microcode storage, the entry point vector comprising a first indicator specifying a number of clock cycles associated with the first microcode flow, initiate the microcode storage, wherein the microcode storage inserts microinstructions of the first microcode flow into an instruction queue, count clock cycles after initiating the microcode storage, and decode a second instruction without first receiving a return from the microcode storage, wherein the second instruction is decoded at a particular clock cycle based on the number of clock cycles associated with the first microcode flow.

Abstract: A processor includes a microcode storage to store a first microcode subroutine and a microcode caller of the first microcode subroutine. The processor further includes a first microcode alias storage comprising a first plurality of microcode alias locations and a second microcode alias storage comprising a second plurality of microcode alias locations. The processor further includes a first logic, coupled to the first microcode alias storage and to the second microcode alias storage, wherein the first logic is configured to select a first one of a) the first microcode alias storage for storage of a parameter location in one of the first plurality of microcode alias locations or b) the second microcode alias storage for storage of the parameter location in one of the second plurality of microcode alias locations.

Abstract: In accordance with embodiments disclosed herein, there is provided systems and methods for monitoring performance of a processing device to manage non-precise events. A processing device includes a performance counter to increment upon occurrence of a non-precise event in the processing device. The processing device also includes a precise event based sampling (PEBS) enable control communicably coupled to the performance counter. The processing device also includes a PEBS handler to generate and store a PEBS record including an architectural metadata defining a state of the processing device at a time of generation of the PEBS record. The processing device further includes a non-precise event based sampling (NPEBS) module communicably coupled to the PEBS control and the PEBS handler. The NPEBS module causes the PEBS handler to generate the PEBS record for the non-precise event upon overflow of the performance counter.