Invention Grant
- Patent Title: Demand based sync bus operation
- Patent Title (中): 基于需求的同步总线操作
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Application No.: US24615Application Date: 1998-02-17
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Publication No.: US6065086APublication Date: 2000-05-16
- Inventor: Ravi Kumar Arimilli , John Steven Dodson , Derek Edward Williams , Jerry Don Lewis
- Applicant: Ravi Kumar Arimilli , John Steven Dodson , Derek Edward Williams , Jerry Don Lewis
- Applicant Address: NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: NY Armonk
- Main IPC: G06F15/177
- IPC: G06F15/177 ; G06F9/52 ; G06F12/08 ; G06F13/42 ; G06F13/38
Abstract:
A register associated with the architected logic queue of a memory-coherent device within a multiprocessor system contains a flag set whenever an architected operation enters the initiating device's architected logic queue to be issued on the system bus. The flag remains set even after the architected logic queue is drained, and is reset only when a synchronization instruction is received from a local processor, providing historical information regarding architected operations which may be pending in other devices. This historical information is utilized to determine whether a synchronization operation should be presented on the system bus, allowing unnecessary synchronization operations to be filtered. When a local processor issues a synchronization instruction to the device managing the architected logic queue, the instruction is generally accepted when the architected logic queue is empty. Otherwise the architected operation is retried back to the local processor until the architected logic queue becomes empty. If the flag is set when the synchronization instruction is accepted from the local processor, it is presented on the system bus. If the flag is not set when the synchronization instruction is received from the local processor, the synchronization operation is unnecessary and is not presented on the system bus.
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