KR20010078559A - Hierarchical distributed bus arbitration apparatus and method - Google Patents

Abstract

PURPOSE: A bus arbitration apparatus and method is provided to reduce stand-by time of node taken to obtain use authority for bus in an information communication system where a plurality of nodes are arranged in a single board. CONSTITUTION: An apparatus comprises the first arbiter(311) for taking, as an input, bus use request signals from all nodes in a board, selecting the node where the bus use request signal is generated, and applying the bus use request signal to the selected node; and the second arbiter(321) for receiving the bus use request signal, and applying a bus use permit signal to the first arbiter. The second arbiter includes a counter(401) for performing counting operation in accordance with a bus arbitration clock signal, a comparator(402) for comparing ID value of the board and the counted value output from the counter; and a logic AND gate(403) for performing AND logic operation for the comparison result of the comparator and the bus use request signal, and outputting a bus arbitration delay signal.

Description

Tiered Distributed Bus Arbitration Devices and Methods {HIERARCHICAL DISTRIBUTED BUS ARBITRATION APPARATUS AND METHOD}

The present invention relates to a distributed bus arbitration apparatus and method layered in an information communication system, and more particularly, to an apparatus and method for arbitrating the use of a bus for nodes connected to a bus.

In general, an information communication system has a passageway for transferring data between a processor node and a corresponding node. In particular, the bus structure has the advantage of providing a communication path at a low cost, but the nodes connected to the bus need a process of acquiring the license of the bus in order to transmit data using the bus.

An example of a distributed arbitration scheme used when the number of nodes connected in a bus used in a conventional information communication system is large is as shown in FIG. 1.

Referring to FIG. 1, a system bus 100 may be equipped with a plurality of boards 111-11N, and in each board 1 -N, a plurality of nodes 11-NL to use a bus may be provided. Can be configured. Each node has a distributed arbiter 111-1NL to determine when the node acquires a license for the bus. The distributed arbiters 111-1NL are located in all nodes 11-NL that want to use the bus, and give a right to use the bus for only one node at a time.

2 is an internal structural diagram of a conventional distributed arbiter, which includes a counter 201, a comparator 202, and a logical end gate 203.

1 and 2, the counter 201 receives a bus arbitration clock signal, a bus arbitration synchronization signal, and a bus arbitration delay signal to perform a counting operation. Here, the bus arbitration clock signal is applied to the arbiter of all nodes to increase the counter value. The bus arbitration synchronization signal matches the initial value of the counter 201 in order to keep all the counter values in the arbiters connected in the bus at the same value, determines the period in which the counter values are repeated, and the counter 201 value is incremented. When compared with the IDs of all nodes, the counter 201 is operated again from the beginning. The comparator 202 compares the counter value output from the counter 201 with the ID value assigned to each node, and if the values match, the comparator 202 permits the bus to use the bus so that the node has a license for the bus. To the node. Each node generates a bus usage request signal when there is data to be transmitted. When the bus permission signal is input, each node can use the bus. The logical endgate 203 generates a bus arbitration delay signal if the bus usage request signal was already input at the time the bus usage signal occurs, thereby preventing the arbitrator counters at other nodes from increasing. When the transfer of data is complete and the bus usage request signal is removed, the bus arbitration delay signal is also removed, causing the counters of the arbiter to increment again, allowing other nodes to use the bus.

However, a distributed arbiter using such a conventional counter has a disadvantage in that a node waits to use a bus in proportion to the number of nodes connected to the bus. In other words, a conventional distributed arbiter must wait until one node uses a bus and then uses the bus until the counter value increases and becomes equal to its node ID. This time depends on the number of nodes connected to the bus. Since there is a large number of nodes connected to the bus because of proportionality, there is a problem in that an unnecessary delay occurs when the number of nodes actually using the bus is small.

Accordingly, an object of the present invention is to provide a layered distributed arbitration apparatus and method for shortening the waiting time for a node to use a bus in an information communication system.

In order to achieve the above object, the present invention provides a centralized arbitrator which receives a bus use request signal from nodes in each board and generates a bus use signal to the node, and mounts each board when the board obtains a license for the bus. At least a distributed arbiter for checking a bus use request of the nodes to input a bus use signal to the centralized arbiter. In addition, the present invention receives a bus use request signal from all nodes in a board in a centralized arbiter, when at least one node generates a bus use request, transferring the bus use request signal to the distributed arbiter; The distributed arbiter receives a bus arbitration clock signal, a bus arbitration synchronization signal and a bus arbitration delay signal, and compares a counter value counted with the ID of the board to generate a bus permission signal for the board. Transmitting the bus permission signal by selecting one of the nodes receiving the bus permission signal from the centralized arbiter and generating the bus use request signal, and transmitting the bus permission signal; Is a process of transmitting data using a bus from an authorized node It is characterized by.

1 is a diagram showing an example of the use of a system bus using a conventional distributed arbiter.

Figure 2 is an internal structure diagram of a conventional distributed arbiter.

3 shows an example of the use of a system bus using a layered distributed arbiter in accordance with the present invention.

4 is an internal structural diagram of a layered distributed bus controller according to the present invention;

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram illustrating an example of a system bus using a layered distributed arbiter according to the present invention, in which a centralized arbiter and a distributed arbiter are provided for each board.

Referring to FIG. 3, the boards 1 to M each have only one distributed arbiter 321 to 32M, and there are a plurality of bus request nodes 1 to N. The bus request nodes 1 -N interwork with the distributed arbiter 310 via the centralized arbiter 311. The distributed arbiters 321 to 32M respectively generate and apply a bus permission signal to the connected central arbiters 311 to 31M. Then, the centralized arbiters 311 to 31M apply the bus use request signals to the connected distributed arbiters 321 to 32M when there is a bus use request from the node. At this time, the centralized arbiters 311 to 31M receive a bus request signal from nodes in the board and select only one node to apply a bus permission signal.

4 shows a configuration of a layered distributed bus arbitration apparatus according to the present invention.

3 and 4, distributed arbiter 321 is comprised of a counter 401, a comparator 402 and a logical end gate 403. As shown in FIG. The counter 401 receives a bus arbitration clock signal, a bus arbitration synchronization signal, and a bus arbitration delay signal to perform a counting operation. The comparator 402 compares the counter value output from the counter 401 with the board ID and transfers the bus permission signal generated according to the result to the centralized arbiter 311. The distributed arbiter 321 according to the present invention obtains the license of the bus on a board basis, unlike the license of the bus on a node basis. The logical AND gate 403 multiplies the signal output from the comparator 402 with the bus use request signal to generate a bus arbitration delay signal according to the result.

On the other hand, the centralized arbiter 311 receives a bus use request from all nodes 1 to N on the board, and when one or more nodes generate a bus use request, the distributed arbiter 321 transmits a bus use request signal. To pass. When the centralized arbiter 311 receives the bus use signal from the distributed arbiter 321, the centralized arbiter 311 selects one of the nodes that generated the bus use request and applies the bus use signal. Then, the node receiving the bus permission signal transmits data using the bus. When the data transmission is completed, the centralized arbiter 311 checks whether another node is generating a bus use request signal. The centralized arbiter 311 applies a bus permission signal to the node if another node generates a bus use request signal. In this case, the centralized arbiter 311 may select a node to which the bus usage request signal is applied from among nodes that generate the bus usage request signal by a random method or a round-robin method.

As described above, the present invention is a hierarchical distributed arbitration method, which first transfers bus licenses in units of boards, so that the counter value in the arbiter increases until it is compared with all board ID values, and then resets to an initial value. If assigned sequentially, the period of the counter is equal to the number of boards. Accordingly, the present invention implements a bus arbitration decision method for a node in each board as a centralized arbiter, and the time for deciding a node to use the bus depends on the number of nodes actually using the bus. That is, in the present invention, the time taken by a node to acquire a bus license again is determined by the period of a counter in the distributed arbiter and the number of nodes to use the bus in each board. In the conventional distributed arbitration scheme, the period of the counter is dependent on the number of nodes using the bus, but in the layered distributed arbitration scheme according to the present invention, it is dependent on the number of boards mounted on the bus. Therefore, the present invention has the advantage of reducing the waiting time for the bus usage in the information communication system in which a plurality of nodes are implemented in one board as compared with the prior art. In addition, the present invention has the advantage that the efficiency of the bus can be increased more often because the usage rights of the nodes in the board are different from board to board, so that the nodes with high usage are more frequently licensed. In addition, the present invention has a merit that the implementation cost can be reduced because the number of arbiters can be smaller than the number of nodes as a distributed distributed arbitration method.

Claims (9)

In the distributed bus arbitration apparatus layered in an information communication system, A first arbitrator which receives a bus use request signal from all nodes in the board, selects a node where the bus use request signal is generated, and applies a bus grant request signal; And a second arbitrator configured to receive a bus use request signal from the first arbitrator and apply the bus use permission signal to the first arbitrator. The method of claim 1, wherein the first mediator, And applying the bus permission signal to a node selected by a random method among nodes generating the bus usage request signal. The method of claim 1, wherein the first mediator, And applying the bus permission signal to a node selected by a round robin method among nodes generating the bus use request signal. The method of claim 1, wherein the second mediator A counter receiving a bus arbitration clock signal, a bus arbitration synchronization signal and a bus arbitration delay signal to perform a counting operation according to the bus arbitration clock signal; A comparator for comparing an ID value of the board and a counting value output from the counter; And a logical AND gate generating the bus arbitration delay signal by performing an AND operation on the comparison result of the comparator and the bus use request signal. In a distributed bus arbitration method layered in an information communication system having at least a distributed arbiter and a centralized arbiter for each board, Transmitting a bus use request signal to the distributed arbiter when the centralized arbiter receives a bus use request signal from all nodes in the board and generates one or more bus use requests; In the distributed arbiter, a bus arbitration clock signal, a bus arbitration synchronization signal, and a bus arbitration delay signal are received to compare a counter value and ID of the board to generate a bus permission signal for the board, thereby generating the centralized arbitration. To send to the flag, Receiving the bus permission signal from the centralized arbiter and selecting one of the nodes that generated the bus use request signal to apply the bus permission signal; And transmitting data by using a bus at a node receiving the bus permission signal. The method of claim 5, And receiving the bus use request signal from the distributed arbiter and performing a logical AND with the bus use request signal to generate the bus arbitration delay signal. The method of claim 5, When the data transmission of the node is completed, checking whether another node is generating a bus use request signal in the centralized arbiter, and applying a bus permission signal to a node generating a bus use request signal; Characterized in that the method. The method of claim 5, And applying the bus permission signal to a node selected by a random method among nodes generating the bus use request signal in the centralized arbiter. The method of claim 5, And applying the bus permission signal to a node selected by a round robin method among nodes generating the bus use request signal in the centralized arbiter.