Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
1999-01-08
2001-12-11
Thai, Tuan V. (Department: 2186)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
C711S151000, C711S154000
Reexamination Certificate
active
06330646
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to memory systems; more particularly, the present invention relates to arbitration policies in a Unified Memory Architecture (UMA).
BACKGROUND OF THE INVENTION
Typical computer systems are implemented using at least two memory subsystems that help to control access to a memory system by requesting agents. The two subsystems are typically a main memory subsystem and a graphics local memory subsystem. The main memory subsystem includes a system memory controller, while the graphics local memory subsystem includes a graphics memory controller. Two memory subsystems are typically necessary for supporting traffic requirements of all requests to access the system memory within an acceptable time latency. Thus, the dual memory architecture provides a performance benefit for typical computer systems. Nevertheless, the additional cost of including a second memory subsystem increases the manufacturing costs of typical computer systems.
Computer systems that include a Unified Memory Architecture combine the functionality of the main memory subsystem and the graphics local memory subsystem. Computer systems with a UMA are obviously less expensive to manufacture due to the absence of a second memory controller (i.e., the graphics memory controller). However, the additional graphics requests to access the system memory typically overload the common system memory controller. Thus, typical UMA computer systems suffer a significant reduction in performance due to the overload of traffic requests at the system memory controller. Consequently, an arbitration policy is needed to balance the demand for system memory and to maximize the available bandwidth in a UMA computer system.
SUMMARY OF THE INVENTION
According to one embodiment, a computer system is disclosed that includes a memory and a memory controller coupled to the memory. The memory controller includes an arbitration unit that may be programmed to operate according to a first arbitration mode or a second arbitration mode.
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Clohset Steve J.
Diep Trung A.
Gandhi Wishwesh A.
Piazza Thomas A.
Sreenivas Aditya
Blakely , Sokoloff, Taylor & Zafman LLP
Intel Corporation
Thai Tuan V.
LandOfFree
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