Method and apparatus for increased performance of a parked data bus in the non-parked direction
US6542949B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 1999 |
| Grant date | Apr 1, 2003 |
| Priority date | — |
| Expiry date | Nov 8, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/1657
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A distributed system structure for a large-way, symmetric multiprocessor system using a bus-based cache-coherence protocol is provided. The distributed system structure contains an address switch, multiple memory subsystems, and multiple master devices, either processors, I/O agents, or coherent memory adapters, organized into a set of nodes supported by a node controller. The node controller receives transactions from a master device, communicates with a master device as another master device or as a slave device, and queues transactions received from a master device. Since the achievement of coherency is distributed in time and space, the node controller helps to maintain cache coherency. In addition, a bus arbiter in the node controller parks a data bus towards a memory subsystem. The node controller does not use data buffer reservations. The data bus grant line to the memory controller is overloaded to use it as a back-pressure, get-off-the-bus signal as well as a normal data bus grant line. The fairness of the bus is thereby increased by creating a mechanism for getting a “parked” device off the data bus without the use of another dedicated signal between physical …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.