Oracle America, Inc.

National Semiconductor Corporation

Sun Microsystems, Inc.

Ampere Computing LLC

Macom Connectivity Solutions, LLC

Richard Win Thaik

John Gregory Favor

Joseph Byron Rowlands

Matthew Ashcraft

Leonard Eric Shar

Christopher Patrick Nelson

Ivan Pavle Radivojevic

Debra J Worsley

Seungyoon Peter Song

Brian C Edem

Geetha N Rangan

Michael T Werstlein

Various aspects provide for facilitating prediction of instruction pipeline hazards in a processor system. A system comprises a fetch component and an execution component. The fetch component is configured for storing a hazard prediction associated with a group of memory access instructions in a buffer associated with branch prediction. The execution component is configured for executing a memory access instruction associated with the group of memory access instructions as a function of the hazard prediction entry. In an aspect, the hazard prediction entry is configured for predicting whether the group of memory access instructions is associated with an instruction pipeline hazard.

Hazard prediction for a group of memory access instructions using a buffer associated with branch prediction

Various aspects provide for detecting ordering violations in a memory system. A system includes a prediction component and an execution component. The prediction component predicts whether a load instruction in the system is associated with an instruction pipeline hazard. The execution component allocates the load instruction to a queue buffer in the system in response to a prediction that the load instruction is not associated with the instruction pipeline hazard.

Allocation of load instruction(s) to a queue buffer in a processor system based on prediction of an instruction pipeline hazard

A method and apparatus for optimizing a sequence of operations adapted for execution by a processor is disclosed to include associating with each register a symbolic expression selected from a set of possible symbolic expressions, locating an operation, if any, that is next within the sequence of operations and setting that operation to be a working operation, where the working operation has associated therewith a destination register and zero or more source registers, and processing the working operation when the working operation and any symbolic expressions of its source registers, if any, match at least one of a set of rules, where each rule specifies that the working operation must match a subset of the operation set, where each rule also specifies that the symbolic expressions, if any, of any source registers of the working operation must match a subset of the possible symbolic expressions, and where the rule also specifies a result, then posting the result as the symbolic expression of the destination register.

Symbolic renaming optimization of a trace

An instruction processing circuit includes a decoder circuit operable to receive a sequence of instructions and to decode the received sequence of instructions into a first type of sequence of operations, and a trace builder circuit operable to receive at least a portion of the sequence of operations of the first type and to generate, based thereon, a second type of sequence of operations, where the at least a portion of the sequence of operations of the first type represents a first portion of the sequence of instructions, where the first portion of the sequence of instructions includes at most one conditional control transfer instruction that, when present, ends the first portion of the sequence of instructions, and where the sequence of operations of the second type also represents the first portion of the sequence of instructions.

Trace unit

A method and system of ensuring coherency of a sequence of instructions to be executed by a processor having a trace unit and an execution unit includes grouping at least a portion of the sequence of instructions to form at least one trace where a status of the at least one trace is set to a verified status when the at least one trace is formed; holding in the at least one trace a coherency component that includes a pointer to a physical address of the at least one trace; receiving, based on the coherency component, the pointer to the physical address as associated with an invalidating event, and in response thereto, setting the status of the at least one trace to be an unverified status; and preventing the at least one trace from being executed when the status of the at least one trace is the unverified status.

System and method for ensuring coherency in trace execution

An instruction processing circuit for a processor is disclosed. The instruction processing circuit is adapted to provide one or more sequence of operations, based on one or more sequence of instructions, to an execution unit of the processor. The instruction processing circuit comprises at least one cache circuit and the processing circuit includes a sequencer and a page translation buffer coupled to the sequencer for trace verification and maintaining coherency between a memory and the at least one cache.

Method and system for utilizing a common structure for trace verification and maintaining coherency in an instruction processing circuit

An instruction processing circuit for a processor, where the instruction processing circuit is adapted to provide one or more sequence of operations, based on one or more sequence of instructions, to an execution circuit of the processor. The instruction processing circuit includes a cache circuit operable to store a second type of sequence of operations that represents at least a portion of a first type of sequence of operations, where the sequence of operations of the second type includes at most one control transfer that, when present, ends a first portion of a sequence of instructions, where the cache circuit is further configured to store a third type of sequence of operations that represents a set of at least two sequences of operations.

Trace unit with a decoder, a basic-block cache, a multi-block cache, and sequencer

An instruction processing circuit includes a decoder circuit, a basic block builder circuit, a multi-block builder circuit, first and second predictor circuits, and a sequencer circuit, where the sequencer circuit is operable, in a first environment, to cause the first predictor circuit to generate a prediction for a particular conditional branch op concurrently with the second predictor circuit generating a prediction for another particular conditional branch op, where the sequencer circuit is also operable, in a second environment, to cause the first predictor circuit to generate a prediction for the particular conditional branch op sequentially with the second predictor circuit generating a prediction for the another particular conditional branch operation.

Concurrent vs. low power branch prediction

An instruction processing circuit includes an instruction cache, a decoder configured to receive at least one of the instructions and to generate, based thereon, a decoder sequence of at least one operation. The circuit includes a basic block cache that includes a basic block sequence of at least one of the operations. The basic block sequence is derived from at least one of the decoder sequences and includes at most one conditional control transfer operation. The circuit includes a multi-block cache that includes a multi-block sequence consisting of at least one of the operations derived from two or more smaller op sequences. A sequencer is configured to generate a prediction for the result of a conditional control transfer operation, select the next sequence of operations, and provide an indication of the next sequence to the instructions cache, the basic block cache, and the multi-block cache.

Instruction cache, decoder circuit, basic block cache circuit and multi-block cache circuit

An instruction processing circuit for a processor includes a decoder circuit, a cache circuit, a sequencer circuit operable to select a next sequence of operations, and an operations fetch circuit operable to convey the next sequence of operations to an execution circuit, receive an indication that a sequencing action of the sequencer circuit is sequencing ahead of the execution circuit, and switch, based on the indication, a source of the operations fetch circuit between the cache circuit and the decoder circuit.

Trace unit with an op path from a decoder (bypass mode) and from a basic-block builder

An instruction processing unit includes a trace builder circuit operable to (i) receive at least a portion of a first type of sequence of operations and to generate, based thereon, a second type of sequence of operations, where the portion includes at most one control transfer instruction that, when present, ends the portion, (ii) receive sets of at least two sequences of operations and to generate, based thereon, a plurality of third type of sequences of operations, where a sequence of operations of the third type includes one or more interior control transfer instructions and is generated from the sequence of operations of the second type and another sequence of operations of the third type, and (iii) retrieve the sequence of operations of the second type and the another sequence of operations of the third type from a cache circuit.

Trace unit with a trace builder

A method and system for promoting traces in an instruction processing circuit is disclosed. The method and system comprises determining if a current trace is promotable; and adding the current trace to a sequence buffer if the current trace is promotable. The current trace is marked as promoted and the current trace is marked as a first trace of a multi-block trace. The method and system includes determining if a next trace is promotable; adding the next trace to the sequence buffer if the next trace is promotable; and repeating the above until the next trace is not promotable and then adding the next trace to the sequence buffer if the next trace is not promotable.

Method and system for promoting traces in an instruction processing circuit

A method and apparatus for optimizing a sequence of operations adapted for execution by a processor is disclosed to include associating a symbolic expression with each of at least a subset of the registers, holding a set of dependency indications that specify for each particular symbolic expression which, if any, of the other symbolic expressions must be emitted as operations prior to emitting the particular symbolic expression, locating an operation, if any, that is next within the sequence of operations and setting that operation to be a working operation and processing the working operation. Processing is performed by handling the working operation by a combination of updating zero or more of the symbolic expressions and emitting zero or more of the symbolic expressions as operations, identifying which, if any, of the symbolic expressions that were updated in process were updated such that they must be emitted prior to which other, if any, of the symbolic expressions, and then updating the dependency indicators to include any such dependencies, and identifying which, if any, of the symbolic expressions that were updated in process were updated such that they no longer need to be emitted prior to which other, if any, of the symbolic expressions, and then updating the dependency indicators to remove any such dependencies.

Emit vector optimization of a trace

A method of determining a reason for a trace to be aborted includes receiving at least two incoming indications of occurrences of abort triggers stemming from the execution of at least two of the operations that are different from each other, where each of the abort triggers has an associated abort priority level, and where the trace represents multiple instructions. The method further includes prioritizing among the abort triggers for the trace based on the abort priority level of each abort trigger, where the prioritizing does not take into account a correspondence between operations and instructions and where the prioritizing selects as a pending abort reason one or more of the abort triggers that have the same abort priority level, and where that abort priority level is the highest among the abort priority levels of the abort triggers for the trace.

Abort prioritization in a trace-based processor

A method and apparatus for optimizing a sequence of operations adapted for execution by a processor is disclosed to include locating an operation, if any, that is next within the sequence of operations and setting a current operation to be that operation. The current operation is processed as follows: a) de-activating, if not already de-activated, a consumed indicator associated with the current operation; and b) when the current operation is of the producer type, then activating, if not already activated, a producer indicator associated with the current operation, and locating a first set of operations, if any, that i) are earlier in the sequence of operations than the current operation, ii) have their associated producer indicator activated, and iii) have their associated consumed indicator de-activated, and then de-activating the producer indicator associated with each operation in the first set. When the current operation is of the consumer type, then locating a second set of operations, if any, that are earlier in the sequence of operations than the current operation, and then activating, if not already activated, the consumed indicator associated with each operation in the second set.

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San Jose, CA, United States of America

Richard Win Thaik