Invention Application
- Patent Title: CANCEL AND REPLAY PROTOCOL SCHEME TO IMPROVE ORDERED BANDWIDTH
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Application No.: US15856799Application Date: 2017-12-28
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Publication No.: US20190205280A1Publication Date: 2019-07-04
- Inventor: Vydhyanathan Kalyanasundharam , Eric Christopher Morton , Chen-Ping Yang , Amit P. Apte , Elizabeth M. Cooper
- Applicant: Advanced Micro Devices, Inc.
- Main IPC: G06F13/42
- IPC: G06F13/42 ; G06F13/364 ; G06F12/0806 ; G06F12/0808 ; G06F12/0811

Abstract:
Systems, apparatuses, and methods for implementing a cancel and replay mechanism for ordered requests are disclosed. A system includes at least an ordering master, a memory controller, a coherent slave coupled to the memory controller, and an interconnect fabric coupled to the ordering master and the coherent slave. The ordering master generates a write request which is forwarded to the coherent slave on the path to memory. The coherent slave sends invalidating probes to all processing nodes and then sends an indication that the write request is globally visible to the ordering master when all cached copies of the data targeted by the write request have been invalidated. In response to receiving the globally visible indication, the ordering master starts a timer. If the timer expires before all older requests have become globally visible, then the write request is cancelled and replayed to ensure forward progress in the fabric and avoid a potential deadlock scenario.
Public/Granted literature
- US10540316B2 Cancel and replay protocol scheme to improve ordered bandwidth Public/Granted day:2020-01-21
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