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EP0380857A2
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Arbitrating communication requests in a multi-processor computer system
Assignee: Digital Equipment Corp
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Filing: 1989-09-21
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Granted: —
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Expires: 2009-09-21
Abstract
Abstract Incoming communication requests to a computer system are stored, and from them are selected, on the basis of a pre-defined prioritising scheme, commands corresponding to requests that are to be arbitrated. There is then generated a first vector defining all system resources that are required for executing the command. A second vector is generated representative of all system resources that are in fact available. The first and second vectors are compared, and the selected command is honoured if all corresponding required resources are available; otherwise, the request corresponding to the command is placed on reserved status, and the availability of corresponding required resources for the reserved request is rechecked, and the reserved request is subsequently honoured by executing the associated command when corresponding reserved resources become available.
Inventors
- 👤 Michael E. Flynn
- 👤 Tryggve Fossum
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 02:16
CPC Classifications
G; G06; G06F; G06F9/00; G06F9/06; G06F9/46; G06F9/52
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
126 words
A method of arbitrating requests for the allocation of computer system resources, the requests being associated with corresponding commands to be executed; the method being characterised by: receiving a command to be arbitrated; generating a first vector defining system resources required for executing the received command; generating a second vector representative of the system resources that a presently available; comparing the first and second vectors; executing the received command in the event that the comparing indicates that the system resources required for executing the command are available, and otherwise: (i) placing the command on reserved status, (ii) reserving the required system resources for executing the received command, and (iii) executing the received command when the required system resources for executing the received command have become available.
Claim 2
Independent Claim
126 words
A method of arbitrating requests for the allocation of computer system resources, the requests being associated with corresponding commands to be executed; the method being characterised by: receiving a command to be arbitrated; generating a first vector defining system resources required for executing the received command; generating a second vector representative of the system resources that a presently available; comparing the first and second vectors; executing the received command in the event that the comparing indicates that the system resources required for executing the command are available, and otherwise: (i) placing the command on reserved status, (ii) reserving the required system resources for executing the received command, and (iii) executing the received command when the required system resources for executing the received command have become available.
Claim 3
Dependent Claim
27 words
An arbitration method as claimed in Claim 1 wherein the received command is a command selected according to a priority scheme from a stored plurality of commands.
Claim 4
Dependent Claim
152 words
An arbitration method as claimed in Claim 2 wherein the priority scheme includes, for the stored commands: a first arbitration pass (the "reserve pass") during which storage locations in which the commands are stored are polled and the commands arbitrated by executing commands for which corresponding reserved resources are available and placing on reserved status commands for which system resources are not available; a second arbitration pass (the "recheck" pass) during which reserved commands are executed by executing those reserved requests for which the required system resources have become available at the time and reserving system resources for those reserved commands for which such required system resources are not available at the time; and a third arbitration pass (the "non-reserve" pass) during which those new commands stored in the storage locations subsequent to the previous "reserve" pass are arbitrated by executing those new commands for which the required system resources are available.
Claim 5
Dependent Claim
35 words
An arbitration method as claimed in Claim 3 wherein after execution of the "reserve" pass, successive "recheck" and "non-reserve" passes are executed alternatively until all commands reserved during the initial "reserve" pass have been executed.
Claim 6
Independent Claim
155 words
A method of arbitrating requests for the allocation of computer system resources, the requests being associated with commands to be executed; the method being characterised by: storing incoming requests; selecting on the basis of a prioritising scheme, requests to be arbitrated; extracting the command corresponding to each request selected for being arbitrated; generating a first vector defining the system resources required for executing the extracted command; generating a second vector representative of the system resources that are available at the time the selected request is being arbitrated; comparing the first and second vectors; honouring the command if the corresponding required resources are available, otherwise placing the request corresponding to the command on reserved status; reserving the required resources corresponding to a reserved request if the resources are not available when the reserved request is being arbitrated; and honouring the reserved requests by subsequently executing the associated command when the corresponding reserved resources have become available.
Claim 7
Independent Claim
155 words
A method of arbitrating requests for the allocation of computer system resources, the requests being associated with commands to be executed; the method being characterised by: storing incoming requests; selecting on the basis of a prioritising scheme, requests to be arbitrated; extracting the command corresponding to each request selected for being arbitrated; generating a first vector defining the system resources required for executing the extracted command; generating a second vector representative of the system resources that are available at the time the selected request is being arbitrated; comparing the first and second vectors; honouring the command if the corresponding required resources are available, otherwise placing the request corresponding to the command on reserved status; reserving the required resources corresponding to a reserved request if the resources are not available when the reserved request is being arbitrated; and honouring the reserved requests by subsequently executing the associated command when the corresponding reserved resources have become available.
Claim 8
Dependent Claim
142 words
An arbitration method as claimed in Claim 5 including the following steps: executing a first arbitration pass (the "reserve pass") during which the requests are polled and requests outstanding at the time are arbitrated by honouring requests for which corresponding reserved resources are available and placing on reserved status requests for which the required resources are not available; executing a second arbitration pass (the "recheck" pass) during which reserved requests are arbitrated by honouring those reserved requests for which the required resources have become available at the time, and reserving the required resources for those reserved requests for which such resources are not available at the time; and executing a third arbitration pass (the "non-reserve" pass) during which those new requests stored subsequent to the previous "reserve" pass are arbitrated by honouring those new requests for which the required resources are available.
Claim 9
Dependent Claim
35 words
An arbitration method as claimed in Claim 6 wherein after execution of the "reserve" pass, successive "recheck" and "non-reserve" passes are executed alternatively until all requests reserved during the initial "reserve" pass have been honoured.
Claim 10
Dependent Claim
117 words
A multi-processor computer system including: means (113, 115) for storing incoming requests (112) from system units thereof and the commands (113) associated therewith, means for selecting the command associated with a selected one of the stored requests for arbitration, means for determining whether or not the system resources required for executing the selected command are available at the time of arbitration, means for initiating the honouring of the request if the required resources are available, means for reserving the required resources if the resources are not available in such a manner that the reserved resources are made unavailable to subsequent requests, and means for initiating the honouring of reserved requests when the corresponding reserved resources become available.
Claim 11
Dependent Claim
117 words
A multi-processor computer system including: means (113, 115) for storing incoming requests (112) from system units thereof and the commands (113) associated therewith, means for selecting the command associated with a selected one of the stored requests for arbitration, means for determining whether or not the system resources required for executing the selected command are available at the time of arbitration, means for initiating the honouring of the request if the required resources are available, means for reserving the required resources if the resources are not available in such a manner that the reserved resources are made unavailable to subsequent requests, and means for initiating the honouring of reserved requests when the corresponding reserved resources become available.
Claim 12
Dependent Claim
72 words
A multi-processor computer system as claimed in Claim 8 wherein the means for determining whether or not resources required by a selected command are available comprises: means (119) for generating a first resource vector identifying the resources required for executing the selected command, means (121) for generating a second resource vector representing the system resources available at the time of arbitration, and means (123) for comparing the first and second resource vectors.
Claim 13
Dependent Claim
90 words
A multi-processor computer system as claimed in Claim 9 wherein the means (113, 115) for storing incoming requests and associated commands includes: prioritising means (113) for accepting incoming requests and generating, on the basis of a prioritising scheme, a command signal indicative of a selected one of the stored commands corresponding to a selected request that has to be arbitrated, and means (117) for extracting a selected stored command on the basis of the control signal and relaying the extracted command to the means for generating the first resource vector.
Claim 14
Dependent Claim
49 words
A multi-processor system as claimed in Claim 10 further comprising means for making the reserved resources unavailable to subsequent requests by adjusting the second resource vector in correspondence with the reserved resources, wherein the means for initiating the honouring of requests being responsive to the adjusted second resource vector.
References Cited (Backward Citations)
No citation records indexed.
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