Apple Inc.

Tellabs San Jose, Inc.

Vivek Venkatraman

Sandeep Kumar Gupta

Tyler J Huberty

Eric Jason Furbish

Srinivasa Rangan Sridharan

Stephan G Meier

Balaji Rajagopalan

Stephen G Meier

Ilya Granovsky

Mridul Agarwal

Peter G Soderquist

Ravindra Sunkad

Chandan Shantharaj

Sanjay Khanna

Ramkumar Krishnamoorthy

David S Curry

Tom Greenshtein

Yanran Yang

Man-Tung T Hsiao

Sahil Kapoor

Amanvir Singh Sidana

Ajay Virginkar

An apparatus includes a plurality of coherent agents, and a coherence directory that includes directory ways for storing coherency information. The coherence directory may be configured to determine that a cache block that is not currently cached among the coherent agents, is stored in a first coherent agent. The coherence directory may be further configured to, in response to this determination, create a particular entry in a selected one of the directory ways. The coherence directory may also be configured to send, to the first coherent agent, an indicator identifying a directory way that includes the entry. In response to a second coherent agent caching the cache block, the coherence directory may update the entry to include the second coherent agent. The first and second coherent agents may be configured to receive copies of the indicator, and to store their copy in locations associated with the cache block.

Coherence directory way tracking in coherent agents

An apparatus includes a cache memory circuit, a prefetcher circuit, and a prefetch deny list circuit, including a plurality of entries, may be included. The cache memory circuit may be configured to store information retrieved from a lower-level memory. The prefetcher circuit may be configured to generate a prefetch request for a particular prefetch address. The prefetch deny list circuit may be configured to allocate, in response to an indication from the cache memory circuit that a previously prefetched address went unused, a given entry, of the plurality of entries, for the previously prefetched address. The prefetch deny list circuit may be further configured to determine whether a particular address for a particular prefetch request corresponds to an active one of the plurality of entries. In response to a determination that a particular active entry corresponds to the particular address, prefetch deny list circuit may deny the particular prefetch request.

Deny list for a memory prefetcher circuit

A cache may store critical cache lines and non-critical cache lines, and may attempt to retain critical cache lines in the cache by, for example, favoring the critical cache lines in replacement data updates. Multiple levels of criticality may be available for a given cache line and cache circuitry may adjust the criticality value of in response to a criticality event. One or more upper criticality levels may be masked when selecting a victim cache line for replacement.

Criticality-informed caching policies with multiple criticality levels

A cache may store critical cache lines and non-critical cache lines, and may attempt to retain critical cache lines in the cache by, for example, favoring the critical cache lines in replacement data updates, retaining the critical cache lines with a certain probability when victim cache blocks are being selected, etc. Criticality values may be retained at various levels of the cache hierarchy. Additionally, accelerated eviction may be employed if the threads previously accessing the critical cache blocks are viewed as dead.

Mitigating retention of previously-critical cache lines

Criticality-informed caching policies

A method or corresponding apparatus in an exemplary embodiment of the present invention monitors an operational status of network links and retrieves or receives the operational status. The operational status is stored (e.g., within 50 msec) on an ongoing basis. The operational status corresponds to an operational LSP from among a primary LSP and secondary LSP(s) used to service traffic via the network links to maintain network connectivity via the LSPs. The secondary LSP(s) may be either a bypass LSP or a backup LSP, where each LSP is Fast Re-route (FRR) enabled. Further, correspondence between the primary LSP, secondary LSP(s), and the network links may be tracked. In order to deliver network traffic via the operational LSP known to service traffic between the source and destination, a link identifier may be used. The link identifier is determined from the source and destination information within the network traffic.

Method and apparatus for maintaining network connectivity via label switched path(s)

A method or corresponding apparatus in an exemplary embodiment of the present invention determines how many copies of a multicast packet are to be sent, as copies, to multiple destinations based on information in the multicast packet and a group (e.g., bridge node) with which the packet is associated. The copies of the multicast packets are then generated. After generating the copies, an action to take for each copy is determined. This determination is made using the information in the multicast packet and based on the group with which the packet is associated. After the action is determined for each copy, the action is performed on each copy. Through use of an embodiment of the present invention, memory space is conserved, allowing for continued use of a device in a multicast environment of an ever growing network, such as the Internet.

Method and apparatus for multicast forwarding

Growing community of inventors

Santa Clara, CA, United States of America

Vivek Venkatraman