Hewlett-packard Development Company, L.p.

Globalfoundries Inc.

Rajen S Ramchandani

Alexander J Branover

Samuel Hammond Duncan

David W Hartwell

Steven Ho

Andrej Kocev

Jeffrey Willcox

Roger Pannel

A processor may comprise one or more cores, where each respective core may comprise one or more state registers, and non-volatile memory configured to store microcode instructions executed by the respective processor core. The processor may further comprise a power management controller (PMC) interfacing with each respective core, and a state monitor (SM) interfacing with the PMC. The PMC may be configured to communicate with each respective core, such that microcode executed by the respective processor core may recognize when a request is made to transition the respective core to a low-power state. The microcode may communicate the request to the PMC, which may in turn determine if the request is for the respective core to transition to a zero-power state. If it is, the PMC may communicate with the SM to determine whether to transition the respective processor core to the zero-power state, and initiate transition to the zero-power state if a determination to transition to the zero-power state is made.

Protocol for transitioning in and out of zero-power state

A method and apparatus for accommodating the speed requirements of a DMA read request from PCI protocol I/O devices attached via a DMA to a multiprocessor system mesh. A bridge between the device controller and the mesh is described which buffers the data from the memory in cache lines from which the data is delivered finally to the I/O device. The system is adaptive in that the number of cache lines required in past reads are remembered and used to determine if the number of cache lines is reduced or increased.

Adaptive data fetch prediction algorithm

Growing community of inventors

Arlington, MA, United States of America

Rajen S Ramchandani