Apple Inc.

Oracle International Corporation

Oracle America, Inc.

Sun Microsystems, Inc.

Gideon N Levinsky

Mridul Agarwal

Manish K Shah

Brian Robert Mestan

Richard F Russo

Christopher M Tsay

Paul Caprioli

Michael Lance Karm

Shailender Chaudhry

Lior Zimet

Tal Kuzi

Shih-Chieh Wen

Martin Karlsson

Charles E Tucker

Jeffrey E Gonion

Pradeep Kanapathipillai

Sherman H Yip

James Vash

John D Pape

Nikhil Gupta

John H Kelm

Francesco Spadini

Jeff Gonion

Deepak Limaye

Jared Smolens

Robert T Golla

Yuan C Chou

Stephan G Meier

Tyler J Huberty

Matthew B Smittle

Kulin N Kothari

Murali Krishna Inaganti

Jiejun Lu

Khondakar Ahmed Mujtaba

Pankaj Lnu

Samson S Wong

Kandasamy Aravinthan

Shahar Dor

Richard T Van

Techniques are disclosed relating to data synchronization barrier operations. A system includes a first processor that may receive a data barrier operation request from a second processor include in the system. Based on receiving that data barrier operation request from the second processor, the first processor may ensure that outstanding load/store operations executed by the first processor that are directed to addresses outside of an exclusion region have been completed. The first processor may respond to the second processor that the data barrier operation request is complete at the first processor, even in the case that one or more load/store operations that are directed to addresses within the exclusion region are outstanding and not complete when the first processor responds that the data barrier operation request is complete.

DSB operation with excluded region

An interrupt delivery mechanism for a system includes and interrupt controller and a plurality of cluster interrupt controllers coupled to respective pluralities of processors in an embodiment. The interrupt controller may serially transmit an interrupt request to respective cluster interrupt controllers, which may acknowledge (Ack) or non-acknowledge (Nack) the interrupt based on attempting to deliver the interrupt to processors to which the cluster interrupt controller is coupled. In a soft iteration, the cluster interrupt controller may attempt to deliver the interrupt to processors that are powered on, without attempting to power on processors that are powered off. If the soft iteration does not result in an Ack response from one of the plurality of cluster interrupt controllers, a hard iteration may be performed in which the powered-off processors may be powered on.

Scalable interrupts

An apparatus includes a cache memory circuit, and a hierarchal store queue circuit that further includes a primary queue and a secondary queue. The hierarchal store queue circuit may be configured to write incoming store requests to the primary queue in response to the primary queue currently having capacity, and to write incoming store requests to the secondary queue in response to the primary queue currently not having capacity. The hierarchal store queue circuit may be further configured to commit store requests to the cache memory circuit from the primary queue but not from the secondary queue. In response to a determination that the primary queue currently has capacity, the hierarchal store queue circuit may perform a transfer of at least one store request from the secondary queue to the primary queue.

Hierarchical store queue circuit

In an embodiment, a processor comprises an atomic predictor circuit to predict whether or not an atomic operation will complete successfully. The prediction may be used when a subsequent load operation to the same memory location as the atomic operation is executed, to determine whether or not to forward store data from the atomic operation to the subsequent load operation. If the prediction is successful, the store data may be forwarded. If the prediction is unsuccessful, the store data may not be forwarded. In cases where an atomic operation has been failing (not successfully performing the store operation), the prediction may prevent the forwarding of the store data and thus may prevent a subsequent flush of the load.

Atomic operation predictor to predict whether an atomic operation will complete successfully

In an embodiment, a processor implements a different atomicity size (for memory consistency order) than the operation size. More particularly, the processor may implement a smaller atomicity size than the operation size. For example, for multiple register loads, the atomicity size may be the register size. In another example, the vector element size may be the atomicity size for vector load instructions. In yet another example, multiple contiguous vector elements, but fewer than all the vector elements in a vector register, may be the atomicity size for vector load instructions.

Decoupling atomicity from operation size

Techniques are disclosed relating to filtering access to a content-addressable memory (CAM). In some embodiments, a processor monitors for certain microarchitectural states and filters access to the CAM in states where there cannot be a match in the CAM or where matching entries will not be used even if there is a match. In some embodiments, toggle control circuitry prevents toggling of input lines when filtering CAM access, which may reduce dynamic power consumption. In some example embodiments, the CAM is used to access a load queue to validate that out-of-order execution for a set of instructions matches in-order execution, and situations where ordering should be checked are relatively rare.

Content-addressable memory filtering based on microarchitectural state

In one embodiment, a processor includes a write combining buffer that includes a memory having a plurality of entries. The entries may be allocated to committed store operations transmitted by a load/store unit in the processor, and subsequent committed store operations may merge data with previous store memory operations in the buffer if the subsequent committed store operations are to addresses that match addresses of the previous committed store operations within a predefined granularity (e.g. the width of a cache port). The write combining buffer may be configured to retain up to N entries of committed store operations, but may also be configured to write one or more of the entries to the data cache responsive to receiving more than a threshold amount of non-merging committed store operations in the write combining buffer.

Dynamic adaptive drain for write combining buffer

Atomic operation predictor to predict if an atomic operation will successfully complete and a store queue to selectively forward data based on the predictor

A system and method for efficiently forwarding cache misses to another level of the cache hierarchy. Logic in a cache controller receives a first non-cacheable load miss request and stores it in a miss queue. When the logic determines the target address of the first load miss request is within a target address range of an older pending second load miss request stored in the miss queue with an open merge window, the logic merges the two requests into a single merged miss request. Additional requests may be similarly merged. The logic issues the merged miss requests based on determining the merge window has closed. The logic further prevents any other load miss requests, which were not previously merged in the merged miss request before it was issued, from obtaining a copy of data from the returned fill data. Such prevention in a non-coherent memory computing system supports memory ordering.

Managing serial miss requests for load operations in a non-coherent memory system

A system for generating predictions for a hardware table walk to find a map of a given virtual address to a corresponding physical address is disclosed. The system includes a plurality of memories, which each includes respective plurality of entries, each of which includes a prediction of a particular one of a plurality of buffers which includes a portion of a virtual to physical address translation map. A first circuit may generate a plurality of hash values to retrieve a plurality of predictions from the plurality of memories, where each has value depends on a respective address and information associated with a respective thread. A second circuit may select a particular prediction of the retrieved predictions to use based on a history of previous predictions.

Adaptive tablewalk translation storage buffer predictor

An apparatus includes a buffer configured to store a plurality of instructions previously fetched from a memory, wherein each instruction of the plurality of instructions may be included in a respective thread of a plurality of threads. The apparatus also includes control circuitry configured to select a given thread of the plurality of threads dependent upon a number of instructions in the buffer that are included in the given thread. The control circuitry is also configured to fetch a respective instruction corresponding to the given thread from the memory, and to store the respective instruction in the buffer.

Optimizing thread selection at fetch, select, and commit stages of processor core pipeline

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Cedar Park, TX, United States of America

Gideon N Levinsky