Control device for data stream optimizations in a link interface
AssigneeNVIDIA Corporation
InventorColyn S. Case
Life of this patent
Estimating the term…
Abstract
Optimization logic that optimizes a stream of requests being transmitted onto a link by a link interface unit can be enabled or disabled based on a performance metric that represents a measure of the degree to which a response to a request is likely to be slowed due to congestion, propagation delays, or other bottlenecks in the system. For example, the performance metric can be based on a measured level of link activity due to requests from the transmitting device and/or a prediction as to behavior (e.g., access time) of the target device that receives the stream of requests. The control logic advantageously does not require extra signals to be carried on the bus.
Claims22
A link interface unit for transmitting a stream of data transfer requests from a requesting device to a target device via a link, the link interface unit comprising:
- a request selection circuit configured with an active mode and a pass-through mode, wherein:
- in the active mode the request selection circuit applies an optimization rule to optimize at least a portion of the stream of data transfer requests and selects an optimized data transfer request for transmission onto the link;
- and
- in the pass-through mode the request selection circuit selects a data transfer request from the stream for transmission onto the link without applying the optimization rule;
- the request selection circuit being coupled to receive an enable signal that selects between the active mode and the pass-through mode;
- and
- an optimization control circuit coupled to the request selection circuit and configured to compute a performance metric based on information about one or more transmitted data transfer requests, the performance metric corresponding to a predicted behavior of the target device, the optimization control circuit including a decision circuit configured to assert or deassert the enable signal for the request selection circuit based at least in part on the performance metric.
A method for transmitting data transfer requests onto a link, the method comprising:
- receiving information about each data transfer request transmitted onto the link;
- computing a performance metric based on the received information, wherein the act of computing the performance metric includes measuring a level of link activity, wherein the act of measuring the level of link activity includes measuring a number of pending data transfer requests, and wherein each pending data transfer request is a data transfer request that has been transmitted to a target device and for which a response from the target device has not been received;
- determining whether the performance metric satisfies a threshold condition;
- in the event that the performance metric satisfies the threshold condition, applying an optimization rule to optimize at least a portion of a stream of outgoing data transfer requests and selecting an optimized data transfer request for transmission on the link;
- in the event that the performance metric does not satisfy the threshold condition, selecting an outgoing data transfer request from the stream of outgoing data transfer requests for transmission on the link without applying the optimization rule;
- and
- transmitting the selected data transfer request on the link.
A processor comprising:
- one or more processing cores configured to generate data transfer requests;
- and
- a link interface unit configured to receive a stream of data transfer requests from the one or more processing cores and to transmit the data transfer requests on a link, the link interface unit including:
- a request selection circuit configured with an active mode and a pass-through mode, wherein in the active mode the request selection circuit applies an optimization rule to optimize at least a portion of the stream of data transfer requests and selects an optimized data transfer request for transmission on the link and wherein in the pass-through mode the request selection circuit selects a data transfer request from the stream for transmission on the link without applying the optimization rule;
- the request selection circuit being coupled to receive an enable signal that selects between the active mode and the pass-through mode;
- and
- an optimization control circuit coupled to the request selection circuit and configured to compute a performance metric based on information about one or more transmitted data transfer requests, the performance metric corresponding to a predicted behavior of a target device, the optimization control circuit including a decision circuit configured to assert or deassert the enable signal for the request selection circuit based at least in part on the performance metric.
Dependencies are inferred from the claim text.