Fast first-come first served arbitration method
First Claim
1. A first come first serve scheduler mechanism for a plurality of clients that generate access request for a resource, comprising:
- a signal conversion circuit which converts a plurality of requests into a plurality of associated time stamp input signals;
a time stamp generation circuit which receives said time stamp input signals and generates coded time stamp output values that correspond to an order of receipt of said time stamp input signals, said time stamp generation circuit includes a time stamp counter which counts each time stamp input signal when said time stamp input signal is generated by said signal conversion Circuit and decrements one unit after a client has released the resource;
a plurality of time stamp registers that receive and store said coded time stamp output values; and
,a hifind circuit that reads said plurality of time stamp registers and generates an output signal in accordance with a predetermined hierarchy and which allows a client access to the resource.
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Accused Products
Abstract
A first-come-first-serve ("FCFS") scheduler that routes requests from two or more clients to a single resource. The FCFS scheduler contains a time stamp mechanism which provides a time stamp for each request. The scheduler provides resource access to the client with the oldest generated request and under a predetermined priority scheme in the event of simultaneous requests. The time stamps are generated by adders which add the current value of a time stamp counter with the number of client requests. The time stamp counter is incremented by the output of the adders. The updated value of the counter is decoded into a time stamp output value stored within time stamp registers. A hifind circuit reads the registers and generates an output signal associated with the set of registers, and corresponding client request, with the lowest time stamp. The output signal allows the client to access the resource.
68 Citations
24 Claims
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1. A first come first serve scheduler mechanism for a plurality of clients that generate access request for a resource, comprising:
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a signal conversion circuit which converts a plurality of requests into a plurality of associated time stamp input signals; a time stamp generation circuit which receives said time stamp input signals and generates coded time stamp output values that correspond to an order of receipt of said time stamp input signals, said time stamp generation circuit includes a time stamp counter which counts each time stamp input signal when said time stamp input signal is generated by said signal conversion Circuit and decrements one unit after a client has released the resource; a plurality of time stamp registers that receive and store said coded time stamp output values; and
,a hifind circuit that reads said plurality of time stamp registers and generates an output signal in accordance with a predetermined hierarchy and which allows a client access to the resource. - View Dependent Claims (2, 3, 5, 6)
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4. The mechanism as recited in claim 4, wherein said time stamp generation circuit includes a decoder which converts said second time stamp counter value to said time stamp output value.
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7. A computer system with a first come first serve mechanism, the computer system comprising:
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a resource; a plurality of clients including a first client that generates a first request for access to said resource, and a second client that generates a second request for access to said resource; and a scheduler mechanism coupled to said resource and said plurality of clients, said scheduler includes a signal conversion circuit which converts said requests into a plurality of associated time stamp input signals, a time stamp generation circuit which receives said time stamp input signals and generates coded time stamp output values that correspond to an order of receipt of said time stamp input signals, said time stamp generation circuit includes a time stamp counter which counts each time stamp input signal when said time stamp input signal is generated by said signal conversion circuit and decrements one unit after a client has released the resource, a plurality of time stamp registers that receive and store said coded time stamp output values, and, a hifind circuit that reads said plurality of time stamp registers and generates an output signal in accordance with a predetermined hierarchy, said output signal being provided to a client to allow access to said resource. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A first come first serve scheduler mechanism for a plurality of clients that generate access request for a resource, comprising:
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signal conversion circuit means for converting the requests into a plurality of associated time stamp input signals; time stamp generation circuit means for receiving said time stamp input signals and for generating coded time stamp output values that correspond to an order of receipt of said time stamp input signals, said time stamp generation circuit means includes a time stamp counter means for counting each time stamp input signal when said time stamp input signal is generated by said signal conversion circuit means and decrements one unit after a client has released a resource; time stamp register means for receiving and storing said coded time stamp output values; and
,hifind circuit means for reading said time stamp registers and for generating an output signal in accordance with a predetermined hierarchy and which allows a client access to the resource. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A computer system with first come first serve mechanism, comprising:
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a resource; a plurality of clients including a first client that generates a first request for access to said resource, and a second client that generates a second request for access to said resource; and scheduler means for enabling at least one of said plurality of clients access to said resource, said scheduler means includes signal conversion circuit means for converting said requests into a plurality of associated time stamp input signals, time stamp generation circuit means for receiving said time stamp input signals and for generating coded time stamp output values that correspond to an order of receipt of said time stamp input signals, said time stamp generation circuit means includes a time stamp counter means for counting each time stamp input signal when said time stamp input signal is generated by said signal conversion circuit means and decrements one unit after a client has released the resource, time stamp register means for receiving and storing said coded time stamp output values, and, hifind circuit means for reading said time stamp register means and for generating an output signal that in accordance with a predetermined hierarchy, said output signal being provided to a client to allow access to said resource. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification