公开(公告)号：US10942865B2

公开(公告)日：2021-03-09

申请号：US16440533

申请日：2019-06-13

Applicant: Arm Limited

Inventor： Gurunath Ramagiri ,  Tushar P. Ringe ,  Mukesh Patel ,  Jamshed Jalal ,  Iat Pui Chan ,  Lakshmi Joga Vishnu Vardhan Badukonda

IPC: G06F12/1081 ,  G06F12/0864 ,  G06F12/0877

Abstract: A method and apparatus are provided to enable snoop forwarding to occur together with memory protection. A data processing apparatus in, for instance, the form of a home node forwards a snoop forwarding request on behalf of a requester to a target, the snoop forwarding request being capable of indicating one or more access permissions of the target in relation to the data. A further data processing apparatus in the form of, for instance, a receiver node may receive the snoop forwarding request and based on its own permissions that are provided in the snoop forwarding request, together with the state of the data, either provide a response back to the requester or the home node. In a still further data processing apparatus in the form of, for instance, a Memory Protection Unit (MPU), a regular snoop forwarding request made to a target in relation to data can be forwarded to the target or demoted to a non-forwarding snoop request based on the permissions of the target in relation to the data at the MPU.

公开(公告)号：US20240273025A1

公开(公告)日：2024-08-15

申请号：US18109453

申请日：2023-02-14

Applicant: Arm Limited

Inventor： Wenxuan Zhang ,  Jamshed Jalal ,  Mark David Werkheiser ,  Sakshi Verma ,  Ritukar Khanna ,  Devi Sravanthi Yalamarthy ,  Gurunath Ramagiri ,  Mukesh Patel ,  Tushar P Ringe

IPC: G06F12/0831 ,  G06F12/0871

CPC classification number: G06F12/0833 ,  G06F12/0871

Abstract: A super home node of a first chip of a multi-chip data processing system manages coherence for both local and remote cache lines accessed by local caching agents and local cache lines accessed by caching agents of one or more second chips. Both local and remote cache lines are stored in a shared cache, and requests are stored in shared point-of-coherency queue. An entry in a snoop filter table of the super home node includes a presence vector that indicates the presence of a remote cache line at specific caching agents of the first chip or the presence of a local cache line at specific caching agents of the first chip and any caching agent of the second chip. All caching agents of the second chip are represented as a single caching agent in the presence vector.

公开(公告)号：US11431649B1

公开(公告)日：2022-08-30

申请号：US17214028

申请日：2021-03-26

Applicant: Arm Limited

Inventor： Mukesh Patel ,  Jamshed Jalal ,  Gurunath Ramagiri ,  Tushar P Ringe ,  Mark David Werkheiser

IPC: G06F13/20 ,  G06F13/42 ,  G06F12/0888 ,  G06F15/173 ,  H04L47/80 ,  H04L47/78 ,  H04L47/62 ,  H04L47/762

Abstract: The present disclosure advantageously provides a method and system for allocating shared resources for an interconnect. A request is received at a home node from a request node over an interconnect, where the request represents a beginning of a transaction with a resource in communication with the home node, and the request has a traffic class defined by a user-configurable mapping based on one or more transaction attributes. The traffic class of the request is determined. A resource capability for the traffic class is determined based on user configurable traffic class-based resource capability data. Whether a home node transaction table has an available entry for the request is determined based on the resource capability for the traffic class.

公开(公告)号：US20240273026A1

公开(公告)日：2024-08-15

申请号：US18109454

申请日：2023-02-14

Applicant: Arm Limited

Inventor： Devi Sravanthi Yalamarthy ,  Jamshed Jalal ,  Mark David Werkheiser ,  Wenxuan Zhang ,  Ritukar Khanna ,  Rajani Pai ,  Gurunath Ramagiri ,  Mukesh Patel ,  Tushar P Ringe

IPC: G06F12/084 ,  G06F12/0811 ,  G06F12/0891

CPC classification number: G06F12/084 ,  G06F12/0811 ,  G06F12/0891

Abstract: A data processing apparatus includes one or more cache configuration data stores, a coherence manager, and a shared cache. The coherence manager is configured to track and maintain coherency of cache lines accessed by local caching agents and one or more remote caching agents. The cache lines include local cache lines accessed from a local memory region and remote cache lines accessed from a remote memory region. The shared cache is configured to store local cache lines in a first partition and to store remote cache lines in a second partition. The sizes of the first and second partitions are determined based on values in the one or more cache configuration data stores and may or not overlap. The cache configuration data stores may be programmable by a user or dynamically programmed in response to local memory and remote memory access patterns.

公开(公告)号：US10657055B1

公开(公告)日：2020-05-19

申请号：US16218962

申请日：2018-12-13

Applicant: Arm Limited

Inventor： Jamshed Jalal ,  Mark David Werkheiser ,  Gurunath Ramagiri ,  Mukesh Patel

IPC: G06F12/08 ,  G06F12/0831 ,  G06F12/0804 ,  G06F12/0817

Abstract: An apparatus and method are provided for managing snoop operations. The apparatus has an interface for receiving access requests from any of N master devices that have associated cache storage, each access request specifying a memory address within memory associated with the apparatus. Snoop filter storage is provided that has a plurality of snoop filter entries, where each snoop filter entry identifies a memory portion and snoop control information indicative of the master devices that have accessed that memory portion. When an access request received at the interface specifies a memory address that is within the memory portion associated with a snoop filter entry, snoop control circuitry uses the snoop control information in that snoop filter entry to determine which master devices to subject to a snoop operation. The snoop control circuitry maintains master indication data used to identify a first subset of the plurality of master devices whose accesses to the memory are to be precisely tracked within the snoop filter storage. The first subset comprises up to M master devices, where M is less than N. Each snoop filter entry has a precise tracking field and an imprecise tracking field. When multiple master devices have accessed the memory portion associated with a snoop filter entry, then the precise tracking field is used to precisely identify each master device of those multiple master devices that is within the first subset. When the multiple master devices includes at least one master device that is not in the first subset, then a generic indication is set in the imprecise tracking field.

公开(公告)号：US11550720B2

公开(公告)日：2023-01-10

申请号：US17102997

申请日：2020-11-24

Applicant: Arm Limited

Inventor： Gurunath Ramagiri ,  Jamshed Jalal ,  Mark David Werkheiser ,  Tushar P Ringe ,  Mukesh Patel ,  Sakshi Verma

IPC: G06F12/0815 ,  G06F12/0831

Abstract: Entries in a cluster-to-caching agent map table of a data processing network identify one or more caching agents in a caching agent cluster. A snoop filter cache stores coherency information that includes coherency status information and a presence vector, where a bit position in the presence vector is associated with a caching agent cluster in the cluster-to-caching agent map table. In response to a data request, a presence vector in the snoop filter cache is accessed to identify a caching agent cluster and the map table is accessed to identify target caching agents for snoop messages. In order to reduce message traffic, snoop message are sent only to the identified targets.

公开(公告)号：US20220164288A1

公开(公告)日：2022-05-26

申请号：US17102997

申请日：2020-11-24

Applicant: Arm Limited

Inventor： Gurunath Ramagiri ,  Jamshed Jalal ,  Mark David Werkheiser ,  Tushar P. Ringe ,  Mukesh Patel ,  Sakshi Verma

IPC: G06F12/0815

Abstract: Entries in a cluster-to-caching agent map table of a data processing network identify one or more caching agents in a caching agent cluster. A snoop filter cache stores coherency information that includes coherency status information and a presence vector, where a bit position in the presence vector is associated with a caching agent cluster in the cluster-to-caching agent map table. In response to a data request, a presence vector in the snoop filter cache is accessed to identify a caching agent cluster and the map table is accessed to identify target caching agents for snoop messages. In order to reduce message traffic, snoop message are sent only to the identified targets.

公开(公告)号：US20200301854A1

公开(公告)日：2020-09-24

申请号：US16361728

申请日：2019-03-22

Applicant: Arm Limited

Inventor： Gurunath Ramagiri ,  Tushar P. Ringe ,  Mukesh Patel ,  Jamshed Jalal ,  Ashok Kumar Tummala ,  Mark David Werkheiser

IPC: G06F12/14 ,  G06F12/0817 ,  G06F9/54

Abstract: A system, apparatus and method for protecting coherent memory contents in a coherent data processing network by filtering data access requests and snoop response based on the Read/Write (R/W) access permissions. Requests are augmented with access permissions in memory protection units and the access permissions are used to control memory access by home nodes of the network.