US 7,664,900 B2Granted

Multiprocessor system and method for processing memory access

AssigneesNEC Corporation, NEC Computertechno, Ltd.

InventorsTakeo Hosomi, Yoshiaki Watanabe

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Abstract

When receiving a write message associated with data, an input/output controller issues a write-request message to a home processor node which holds the data in a memory. When receiving the write-request message, a memory controller in the processor node executes a consistency process on the basis of information, regarding the state of the data, stored in a directory, and sends a write-permission message to the input/output controller which has issued the write-request message. In response to the received write-permission message, the input/output controller in an input/output node issues an update message, serving as a write message, to the home processor node. In response to the received update message, the memory controller in the process node updates the data in the main memory. In the above process, when receiving a plurality of write messages from input/output devices, the input/output controller issues write-request messages irrespective of the progress of a preceding write message. After the preceding write message is issued, the input/output controller issues the write messages.

Claims12

Dependent claims

A processor system comprising a plurality of resource nodes connected to a network, a plurality of control nodes connected to the network, and a plurality of controllers, wherein

each of the resource nodes includes a resource holding unit for holding a plurality of resources and a resource information holding unit for managing the states of the resources, each state indicating that the corresponding resource is in a free or locked state,
each of the control nodes includes a plurality of control devices for issuing a plurality of requests associated with resources, each control node, including the control devices which have issued requests, transferring the requests to the corresponding controller, and wherein
at least one controller, which has received the requests, issues a request message to each of resource nodes which hold target resources associated with the requests,
each resource node which has received the request message checks that the target resource is in the free state, and if the target resource is in the free state, changes the state of the target resource to the locked state, and issues a permission message to the at least one controller,
the at least one controller, which has received the permission message, checks that all of permission messages associated with other requests preceding the corresponding request received by the at least one controller have already been received and issues an update message to the resource node which holds the target resource associated with the corresponding request, and
the resource node which has received the update message changes the state of the target resource to the free state.

3 more elements

A method for processing access, the method being applied to a processor system including a plurality of resource nodes connected to a network, a plurality of control nodes connected to the network, and a plurality of controllers, each of the resource nodes including a resource holding unit for holding a plurality of resources and a resource information holding unit for managing the states of the resources, each state indicating that the corresponding resource is in a free or locked state, each of the control nodes including a plurality of control devices for issuing a plurality of requests associated with resources, wherein:

the control device transfers requests to at least one corresponding controller;
the at least one controller issues, in response to the request, a request message to each resource node which holds the target resource associated with the corresponding request,
the resource node checks, in response to the request message, whether the target resource is in the free state, and if the target resource is in the free state, changes the state of the target resource to the locked state, and issues a permission message to the at least one controller;
the at least one controller checks, in response to the permission message, whether all of permission messages associated with other requests preceding the corresponding request received by the at least one controller have already been received and issues an update message to the resource node which holds the target resource associated with the corresponding request;
and
the resource node changes, in response to the update message, the state of the target resource to the free state.

3 more elements

Dependencies are inferred from the claim text.