Apple Inc.

James Vash

Gaurav Garg

Harshavardhan Kaushikkar

Per Hakan Hammarlund

Steven R Hutsell

Brian P Lilly

Sergio Kolor

Lital Levy-Rubin

Ramesh B Gunna

Lior Zimet

Sagi Lahav

Jeff Gonion

Richard F Russo

Derek R Kumar

Mridul Agarwal

Pradeep Kanapathipillai

Aditya Kesiraju

Tyler J Huberty

Jonathan M Redshaw

Shawn Munetoshi Fukami

Eran Tamari

Sergio V Tota

Farid Nemati

Steven John Fishwick

Gerard Richard Williams

Sandeep Kumar Gupta

Gregory S Mathews

Bernard Joseph Semeria

Gideon N Levinsky

Andrew J Beaumont-Smith

Srinivasa Rangan Sridharan

John H Kelm

Jason M Kassoff

Christopher M Tsay

Ran A Chachick

Charles E Tucker

Krishna C Potnuru

Rajdeep L Bhuyar

Era K Nangia

Jeffry E Gonion

Manu Gulati

Tal Kuzi

Benjamin K Dodge

Prashant Jain

Michael Bekerman

Tzach Zemer

Dany Davidov

Samer Nassar

Nir Leshem

Mark Pilip

Peter A Lisherness

Zhaoming Hu

Dennis R Bradford

Techniques are disclosed relating to performing remote cache invalidations. In some embodiments, primary processor circuitry is configured to, based on execution of a remote invalidate instruction (e.g., an ISA-defined instruction), send a cache invalidate command to coprocessor circuitry. The coprocessor circuitry includes coprocessor cache circuitry and cache invalidation control circuitry configured to, in response to the cache invalidate command sent by the primary processor, invalidate one or more cache lines in the coprocessor cache circuitry without executing any instructions on the coprocessor circuitry.

Remote cache invalidation

Techniques are disclosed relating to performing remote invalidation of memory access permission information. In some embodiments, primary processor circuitry is configured to, based on execution of a remote permission table invalidate instruction (e.g., an ISA-defined instruction), send a remote invalidate command to secondary processor circuitry. The secondary processor circuitry includes secondary processor permission circuitry and is configured to, in response to the remote invalidate command sent by the primary processor, invalidate one or more entries in the secondary processor permission circuitry. In some embodiments, the secondary processor performs the invalidate without executing any instructions on the secondary processor circuitry.

Invalidation of permission information stored by another processor

A system including a plurality of processor cores, a plurality of graphics processing units, a plurality of peripheral circuits, and a plurality of memory controllers is configured to support scaling of the system using a unified memory architecture.

Scalable system on a chip

A system may include multiple coherent agents, where a given coherent agent includes one or more caches configured to cache data. Memory controller circuitry may control one or more memory circuits from which the one or more caches are configured to cache data and maintain a directory that tracks which of the multiple coherent agent circuits is caching copies of a plurality of cache blocks and states of the cached copies in the multiple coherent agent circuits. A first agent may transmit a first request for a first cache block. The first agent may store, in request buffer circuitry, information corresponding to the first request then detect a second snoop from a second agent circuit to the first cache block. The first agent may absorb the second snoop, including to store information corresponding to the second snoop with the information corresponding to the first request in the request buffer circuitry.

Scalable cache coherency protocol

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

Techniques are disclosed pertaining to utilizing a communication fabric via multiple ports. An agent circuit includes a plurality of command-and-data ports that couple the agent circuit to a communication fabric coupled to a plurality of hardware components that includes a plurality of memory controller circuits that facilitate access to a memory. The agent circuit can execute an instruction that involves issuing a command for data stored at the memory. The agent circuit may perform a hash operation on a memory address associated with the command to determine which one of the plurality of memory controller circuits to which to issue the command. The agent circuit issues the command to the determined memory controller circuit on a particular one of the plurality of command-and-data ports that is designated to the memory controller circuit. The agent circuit may issue all commands destined to that memory controller circuit on that port.

Mechanisms to utilize communication fabric via multi-port architecture

Techniques are disclosed relating to memory error tracking and logging. In some embodiments, a memory cache controller circuitry is configured to track, using multiple circuit entries, numbers of detected correctable errors associated with multiple respective locations, and in response to detecting a threshold number of correctable errors for a particular location, generate a signal to the one or more processors that identifies the particular location. In some embodiments, the memory cache controller circuitry includes multiple circuit entries for tracking uncorrectable errors.

Memory error tracking and logging

A scalable cache coherency protocol for system including a plurality of coherent agents coupled to one or more memory controllers is described. The memory controller may implement a precise directory for cache blocks from the memory to which the memory controller is coupled. Multiple requests to a cache block may be outstanding, and snoops and completions for requests may include an expected cache state at the receiving agent, as indicated by a directory in the memory controller when the request was processed, to allow the receiving agent to detect race conditions. In an embodiment, the cache states may include a primary shared and a secondary shared state. The primary shared state may apply to a coherent agent that bears responsibility for transmitting a copy of the cache block to a requesting agent. In an embodiment, at least two types of snoops may be supported: snoop forward and snoop back.

An integrated circuit (IC) including a plurality of processor cores, a plurality of graphics processing units, a plurality of peripheral circuits, and a plurality of memory controllers is configured to support scaling of the system using a unified memory architecture. For example, the IC may include an interconnect fabric configured to provide communication between the one or more memory controller circuits and the processor cores, graphics processing units, and peripheral devices; and an off-chip interconnect coupled to the interconnect fabric and configured to couple the interconnect fabric to a corresponding interconnect fabric on another instance of the integrated circuit, wherein the interconnect fabric and the off-chip interconnect provide an interface that transparently connects the one or more memory controller circuits, the processor cores, graphics processing units, and peripheral devices in either a single instance of the integrated circuit or two or more instances of the integrated circuit.

A system may include a plurality of processors and a coprocessor. A plurality of coprocessor context priority registers corresponding to a plurality of contexts supported by the coprocessor may be included. The plurality of processors may use the plurality of contexts, and may program the coprocessor context priority register corresponding to a context with a value specifying a priority of the context relative to other contexts. An arbiter may arbitrate among instructions issued by the plurality of processors based on the priorities in the plurality of coprocessor context priority registers. In one embodiment, real-time threads may be assigned higher priorities than bulk processing tasks, improving bandwidth allocated to the real-time threads as compared to the bulk tasks.

Coprocessor context priority

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San Ramon, CA, United States of America

James Vash