公开(公告)号：US10545701B1

公开(公告)日：2020-01-28

申请号：US16104307

申请日：2018-08-17

Applicant: Apple Inc.

Inventor： Gregory S. Mathews ,  Kai Lun Hsiung ,  Lakshmi Narasimha Murthy Nukala ,  Peter Fu ,  Rakesh L. Notani ,  Sukalpa Biswas ,  Thejasvi Magudilu Vijayaraj ,  Yanzhe Liu ,  Shane J. Keil

IPC: G06F3/06

Abstract: Techniques relating to arbitration in a memory controller are disclosed. In some embodiments, the memory controller implements a per-bank priority-based arbitration scheme for different types of memory traffic (e.g., with different quality of service parameters). In some embodiments, the memory controller is configured to provide per-bank overrides to the arbitration scheme based on latency tolerance reported by one or more requesters sending a particular type of memory traffic. Various techniques disclosed herein may improve performance, improve fairness among different types of memory traffic, and/or reduce power consumption.

公开(公告)号：US20180074743A1

公开(公告)日：2018-03-15

申请号：US15263833

申请日：2016-09-13

Applicant: Apple Inc.

Inventor： Robert E. Jeter ,  Liang Deng ,  Kai Lun Hsiung ,  Manu Gulati ,  Rakesh L. Notani ,  Sukalpa Biswas ,  Venkata Ramana Malladi ,  Gregory S. Mathews ,  Enming Zheng ,  Fabien S. Faure

IPC: G06F3/06 ,  G06F1/08

CPC classification number: G06F3/0634 ,  G06F1/08 ,  G06F1/324 ,  G06F3/0625 ,  G06F3/0653 ,  G06F3/0659 ,  G06F3/0673 ,  G06F3/0683 ,  G06F13/1689 ,  G06F13/4243 ,  Y02D10/14 ,  Y02D10/151

Abstract: Systems, apparatuses, and methods for improved memory controller power management techniques. An apparatus includes control logic, one or more memory controller(s), and one or more memory devices. If the amount of traffic and/or queue depth for a given memory controller falls below a threshold, the clock frequency supplied to the given memory controller and corresponding memory device(s) is reduced. In one embodiment, the clock frequency is reduced by one half If the amount of traffic and/or queue depth rises above the threshold, then the clock frequency is increased back to its original frequency. The clock frequency may be adjusted by doubling the divisor used by a clock divider, which enables fast switching between the original rate and the reduced rate. This in turn allows for more frequent switching between the low power and normal power states, resulting in the memory controller and memory device operating more efficiently.

公开(公告)号：US20240095194A1

公开(公告)日：2024-03-21

申请号：US18469905

申请日：2023-09-19

Applicant: Apple Inc.

Inventor： Shane J. Keil ,  Gregory S. Mathews ,  Lakshmi Narasimha Murthy Nukala

IPC: G06F13/16

CPC classification number: G06F13/1626 ,  G06F13/1678 ,  G06F13/1689

Abstract: A memory control circuit coupled to multiple memory ranks may receive read and write requests for a different ranks of the multiple memory ranks. The memory control may allocate write requests to different slots based on the write requests target memory rank, and may adjust the number of slots available for a given memory rank during a write turn to improve write efficiency. The memory control circuit may also determine a number of ranks switches within a read turn based on whether a particular quality-of-service requirement associated with the read requests is being satisfied.

公开(公告)号：US20240094917A1

公开(公告)日：2024-03-21

申请号：US18469730

申请日：2023-09-19

Applicant: Apple Inc.

Inventor： Shane J. Keil ,  Gregory S. Mathews ,  Rakesh L. Notani

IPC: G06F3/06 ,  G06F12/02

CPC classification number: G06F3/0613 ,  G06F3/0656 ,  G06F3/0659 ,  G06F3/0673 ,  G06F12/023

Abstract: A memory control circuit coupled to multiple memory ranks may receive read and write requests for a different ranks of the multiple memory ranks. The memory control may allocate write requests to different slots based on the write requests target memory rank, and may adjust the number of slots available for a given memory rank during a write turn to improve write efficiency. The memory control circuit may also determine a number of ranks switches within a read turn based on whether a particular quality-of-service requirement associated with the read requests is being satisfied.

公开(公告)号：US20230064187A1

公开(公告)日：2023-03-02

申请号：US17455321

申请日：2021-11-17

Applicant: Apple Inc.

Inventor： Rohit K. Gupta ,  Gregory S. Mathews ,  Harshavardhan Kaushikkar ,  Jeonghee Shin ,  Rohit Natarajan

IPC: H04L12/927 ,  H04L12/801 ,  H04L12/825

Abstract: Techniques are disclosed relating to merging virtual communication channels in a portion of a computing system. In some embodiments, a communication fabric routes first and second classes of traffic with different quality-of-service parameters, using a first virtual channel for the first class and a second virtual channel for the second class. In some embodiments, a memory controller communicates, via the fabric, using a merged virtual channel configured to handle traffic from both the first virtual channel and the second virtual channel. In some embodiments, the system limits the rate at which an agent is allowed to transmit requests of the second class of traffic, but requests by the agent for the first class of traffic are not rate limited. Disclosed techniques may improve independence of virtual channels, relative to sharing the same channel in an entire system, without unduly increasing complexity.

公开(公告)号：US20230063772A1

公开(公告)日：2023-03-02

申请号：US17655324

申请日：2022-03-17

Applicant: Apple Inc.

Inventor： Gregory S. Mathews ,  Shane J. Keil

IPC: G06F13/16 ,  G06F1/06

Abstract: Techniques for scheduling memory operations are disclosed in which alternate read/write commands within a multi-bank memory operation are delayed beyond a minimum timing parameter in order to increase memory data bus utilization. The remaining read/write commands are not delayed beyond the minimum timing parameter. Every other clock cycle (e.g., even clock cycles) within the memory operation is reserved for activate commands, while other commands such as sync and read/write are scheduled on the intervening clock cycles (e.g., odd clock cycles). For memory devices for which a sync command (which causes a clock of the memory data bus to start) is to precede a corresponding read/write command by a number of clock cycles that would place it in a cycle reserved for activate commands, a particular operation mode is disclosed in which the memory device internally delays a received sync command.

公开(公告)号：US10901617B2

公开(公告)日：2021-01-26

申请号：US16565386

申请日：2019-09-09

Applicant: Apple Inc.

Inventor： Gregory S. Mathews ,  Shane J. Keil ,  Sukalpa Biswas ,  Lakshmi Narasimha Murthy Nukala ,  Thejasvi Magudilu Vijavaraj

IPC: G06F12/00 ,  G06F3/06

Abstract: A memory controller circuit coupled to a memory circuit that includes multiple banks may receive multiple access requests including a particular access request to a particular bank of the plurality of banks. The particular access request is associated with a particular virtual channel of a plurality of virtual channels. The memory controller circuit may select a given access requests of the multiple access requests based on an arbitration category value associated with a virtual channel of the given access request and modify the arbitration category value in response to selecting the given access request.

公开(公告)号：US10817219B2

公开(公告)日：2020-10-27

申请号：US16129735

申请日：2018-09-12

Applicant: Apple Inc.

Inventor： Lakshmi Narasimha Murthy Nukala ,  Sukalpa Biswas ,  Thejasvi Magudilu Vijavaraj ,  Shane J. Keil ,  Gregory S. Mathews

IPC: G06F3/06 ,  G06F13/16 ,  G06F9/48 ,  G06F9/54

Abstract: A memory controller circuit coupled to multiple memory circuits may receive a read request for a particular one of the memory circuits and insert the read request into one of multiple linked lists that includes a linked list whose entries correspond to previously received read requests and are linked according to respective ages of the read requests. The memory controller circuit may schedule the read request using a head pointer of one of the multiple linked lists.

公开(公告)号：US20200301615A1

公开(公告)日：2020-09-24

申请号：US16896027

申请日：2020-06-08

Applicant: Apple Inc.

Inventor： Shane J. Keil ,  Gregory S. Mathews ,  Lakshmi Narasimha Murthy Nukala ,  Thejasvi Magudilu Vijayaraj ,  Kai Lun Hsiung ,  Yanzhe Liu ,  Sukalpa Biswas

IPC: G06F3/06

Abstract: An apparatus includes a memory circuit and a memory controller circuit. The memory controller circuit may include a write request queue. The memory controller circuit may be configured to receive a memory request to access the memory circuit and determine if the memory request includes a read request or a write request. A received read request may be scheduled for execution, while a received write request may be stored in the write request queue. The memory controller circuit may reorder scheduled memory requests based on achieving a specified memory access efficiency and based on a number of write requests stored in the write request queue.

公开(公告)号：US20200159463A1

公开(公告)日：2020-05-21

申请号：US16751975

申请日：2020-01-24

Applicant: Apple Inc.

Inventor： Gregory S. Mathews ,  Kai Lun Hsiung ,  Lakshmi Narasimha Murthy Nukala ,  Peter Fu ,  Rakesh L. Notani ,  Sukalpa Biswas ,  Thejasvi Magudilu Vijayaraj ,  Yanzhe Liu ,  Shane J. Keil

IPC: G06F3/06

Abstract: Techniques relating to arbitration in a memory controller are disclosed. In some embodiments, the memory controller is configured to transition between read turns and writes turn according to a turn schedule. In some embodiments, the memory controller also receives reports from circuitry requesting memory transactions and determines a current latency tolerance value based on the reports. In some embodiments, the memory controller is configured to switch from a write turn to a read turn prior to a scheduled switch based on the current latency tolerance meeting a threshold value.