Priority control in resource allocation for low request rate, latency-sensitive units
View Patent ↗A mechanism for priority control in resource allocation for low request rate, latency-sensitive units is provided. With this mechanism, when a unit makes a request to a token manager, the unit identifies the priority of its request as well as the resource which it desires to access and the unit's resource access group (RAG). This information is used to set a value of a storage device associated with the resource, priority, and RAG identified in the request. When the token manager generates and grants a token to the RAG, the token is in turn granted to a unit within the RAG based on a priority of the pending requests identified in the storage devices associated with the resource and RAG. Priority pointers are utilized to provide a round-robin fairness scheme between high and low priority requests within the RAG for the resource.
1. A method, in a data processing system, for controlling access to a resource, comprising:
generating and granting a token to a resource allocation group, wherein the resource allocation group comprises one or more requester devices within the data processing system, and wherein the resource allocation group is one of a plurality of resource allocation groups in the data processing system;
obtaining request information from a group of request storage devices, separate from the one or more requester devices and allocated, from a plurality of request storage devices, to the resource allocation group and the resource, wherein the group of request storage devices is separated into a first sub-group of high priority request storage devices and a second sub-group of low priority request storage devices;
selecting requester device from the one or more requester devices to receive the token based on the request information obtained from the group of request storage devices; and
granting the token to the selected requester device, wherein the selected requester device uses the token to access the resource, wherein:
obtaining the request information from the group of request storage devices allocated to the resource allocation group and the resource comprises:
obtaining a value of a first pointer associated with the first sub-group of high priority request storage devices;
obtaining a value of a second pointer associated with a second sub-group of low priority request storage devices;
determining if there is a pending high priority request for access to the resource based on the value of the first pointer; and
determining if there is a pending low priority request for access to the resource based on the value of the second pointer,
selecting the requester device from the one or more requester devices to receive the token based on the request information obtained from the group of request storage devices, comprises:
selecting a requester device associated with the high priority request if a pending high priority request is identified by the value of the first pointer; and
selecting a requester device associated with the low priority request if a pending low priority request is identified by the value of the second pointer and the value of the first pointer indicates that a high priority request is not pending,
a value of the first pointer is incremented to point to a next high priority request storage device in the first sub-group of high priority request storage devices only if a request associated with a current value of the first pointer is dispatched,
a value of the second pointer is incremented to point to a next low priority request storage device in the second sub-group of low priority request storage devices only if a request associated with a current value of the second pointer is dispatched, and
the first sub-group of high priority request storage devices may contain a pending high priority request yet the first pointer may indicate that a high priority request is not pending if the first pointer points to an empty high priority request storage device.