Read control in a computer I/O interconnect
AssigneePLX Technology, Inc.
InventorsJeffrey Michael Dodson, Nagamanivel Balasubramaniyan
Life of this patent
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Abstract
In one embodiment, a method for controlling reads in a computer input/output (I/O) interconnect is provided. A read request is received over the computer I/O interconnect from a first device, the request requesting data of a first size. Then it is determined whether fulfilling the read request would cause the total size of a completion queue to exceed a first predefined threshold. If fulfilling the read request would cause the total size of the completion queue to exceed the first predefined threshold, then the read request is temporarily restricted from being forwarded upstream.
Claims18
A method for controlling reads in a packetized computer input/output (I/O) interconnect compatible with a packetized computer I/O interconnect standard, the method comprising:
- receiving a read request at a root complex over the packetized computer I/O interconnect from a first device compatible with the packetized computer I/O interconnect standard, the request requesting data of a first size;
- determining whether adding the read request to a read request queue at the root complex would cause the total size of requested data in read requests from the first device currently stored in the read request queue to exceed a first predefined threshold, wherein the first predefined threshold is based on a round trip time between the root complex and a destination switch of the read request;
- and
- temporarily restricting the read request from being forwarded upstream to the destination switch of the read request if adding the read request to the read request queue would cause the total size of the requested data in read requests from the first device currently stored in the read request queue to exceed the first predefined threshold.
A root complex compatible with a packetized computer I/O interconnect standard, the root complex comprising:
- an upstream request queue;
- a downstream completion queue;
- an interface to a switch;
- an interface to a first device compatible with the packetized computer I/O interconnect standard;
- and
- a memory controller adapted to:
- receive a read request from the first device first device, the request requesting data of a first size from a device coupled to the switch;
- determine whether adding the read request to the read request queue would cause the total size of requested data in read requests from the first device currently stored in the read request queue to exceed a first predefined threshold, wherein the first predefined threshold is based on a round trip time between the root complex and the switch;
- and
- temporarily restrict the read request from being forwarded upstream to the switch if adding the read request to the read request queue would cause the total size of the requested data in read requests from the first device currently stored in the read request queue to exceed the first predefined threshold.
An apparatus for controlling reads in a packetized computer input/output (I/O) interconnect compatible with a packetized computer I/O interconnect standard, the apparatus comprising:
- means for receiving a read request over the packetized computer I/O interconnect from a first device compatible with the packetized computer I/O interconnect standard, the request requesting data of a first size;
- means for determining whether adding the read request to a read request queue would cause the total size of requested data in read requests from the first device currently stored in the read request queue to exceed a first predefined threshold, wherein the first predefined threshold is based on a round trip time between the means for receiving and a destination switch of the read request;
- and
- means for temporarily restricting the read request from being forwarded upstream to the destination switch of the read request if adding the read request to the read request queue would cause the total size of the requested data in read requests from the first device currently stored in the read request queue to exceed the first predefined threshold.
Dependencies are inferred from the claim text.