摘要:
Embodiments of the present invention execute an anti-prefetch instruction. These embodiments start by decoding instructions in a decode unit in a processor to prepare the instructions for execution. Upon decoding an anti-prefetch instruction, these embodiments stall the decode unit to prevent decoding subsequent instructions. These embodiments then execute the anti-prefetch instruction, wherein executing the anti-prefetch instruction involves: (1) sending a prefetch request for a cache line in an L1 cache; (2) determining if the prefetch request hits in the L1 cache; (3) if the prefetch request hits in the L1 cache, determining if the cache line contains a predetermined value; and (4) conditionally performing subsequent operations based on whether the prefetch request hits in the L1 cache or the value of the data in the cache line.
摘要:
A method for determining whether to store binary information in a fast way or a slow way of a cache is disclosed. The method includes receiving a block of binary information to be stored in a cache memory having a plurality of ways. The plurality of ways includes a first subset of ways and a second subset of ways, wherein a cache access by a first execution core from one of the first subset of ways has a lower latency time than a cache access from one of the second subset of ways. The method further includes determining, based on a predetermined access latency and one or more parameters associated with the block of binary information, whether to store the block of binary information into one of the first set of ways or one of the second set of ways.
摘要:
A method for determining whether to store binary information in a fast way or a slow way of a cache is disclosed. The method includes receiving a block of binary information to be stored in a cache memory having a plurality of ways. The plurality of ways includes a first subset of ways and a second subset of ways, wherein a cache access by a first execution core from one of the first subset of ways has a lower latency time than a cache access from one of the second subset of ways. The method further includes determining, based on a predetermined access latency and one or more parameters associated with the block of binary information, whether to store the block of binary information into one of the first set of ways or one of the second set of ways.
摘要:
Embodiments of the present invention provide a system that replaces an entry in a least-recently-used way in a skewed-associative cache. The system starts by receiving a cache line address. The system then generates two or more indices using the cache line address. Next, the system generates two or more intermediate indices using the two or more indices. The system then uses at least one of the two or more indices or the two or more intermediate indices to perform a lookup in one or more lookup tables, wherein the lookup returns a value which identifies a least-recently-used way. Next, the system replaces the entry in the least-recently-used way.
摘要:
One embodiment of the present invention provides a system that samples instructions on a processor that supports speculative-execution. The system starts by selecting an instruction, wherein selecting an instruction involves selecting an instruction that is received from an instruction fetch unit or a deferred queue, wherein the deferred queue holds deferred instructions which are deferred because of an unresolved data dependency. The system then records information about the selected instruction during execution of the selected instruction, whereby the recorded information can be used to determine the performance of the processor.
摘要:
One embodiment of the present invention provides a system for measuring processor performance during speculative-execution. The system starts by executing instructions in a normal-execution mode. The system then enters a speculative-execution episode wherein instructions are speculatively executed without being committed to the architectural state of the processor. While entering the speculative-execution episode the system enables a speculative execution monitor. The system then uses the speculative execution monitor to monitor instructions during the speculative-execution episode to record data values relating to the speculative-execution episode. Upon returning to normal-execution mode, the system disables the speculative execution monitor. The data values recorded by the speculative execution monitor facilitate measuring processor performance during speculative execution.
摘要:
A technique maintains return address stack (RAS) content and alignment of a RAS top-of-stack (TOS) pointer upon detection of a tail-call elimination of a return-type instruction. In at least one embodiment of the invention, an apparatus includes a processor pipeline and at least a first return address stack for maintaining a stack of return addresses associated with instruction flow at a first stage of the processor pipeline. The processor pipeline is configured to maintain the first return address stack unchanged in response to detection of a tail-call elimination sequence of one or more instructions associated with a first call-type instruction encountered by the first stage. The processor pipeline is configured to push a return address associated with the first call-type instruction onto the first return address stack otherwise.
摘要:
Embodiments of the present invention provide a system that executes a transaction on a simultaneous speculative threading (SST) processor. In these embodiments, the processor includes a primary strand and a subordinate strand. Upon encountering a transaction with the primary strand while executing instructions non-transactionally, the processor checkpoints the primary strand and executes the transaction with the primary strand while continuing to non-transactionally execute deferred instructions with the subordinate strand. When the subordinate strand non-transactionally accesses a cache line during the transaction, the processor updates a record for the cache line to indicate the first strand ID. When the primary strand transactionally accesses a cache line during the transaction, the processor updates a record for the cache line to indicate a second strand ID.
摘要:
A mask is first generated in a general-purpose integer register. The mask is generated by executing a single instruction multiple data (SIMD) instruction on a plurality of operands stored in a plurality of registers and by writing the result to the general-purpose integer register. Next, a conditional-move mask is generated in a register using the mask, and then the conditional-move mask is used in selecting operands from the plurality of operands to generate a result in another register.
摘要:
A circuit for accessing an associative cache is provided. The circuit includes data selection circuitry and an outcome parallel processing circuit both in communication with the associative cache. The outcome parallel processing circuit is configured to determine whether an accessing of data from the associative cache is one of a cache hit, a cache miss, or a cache mispredict. The circuit further includes a memory in communication with the data selection circuitry and the outcome parallel processing circuit. The memory is configured to store a bank select table, whereby the bank select table is configured to include entries that define a selection of one of a plurality of banks of the associative cache from which to output data. Methods for accessing the associative cache are also described.