JPH0334032A - Parallel multiplex control system - Google Patents

Abstract

PURPOSE:To reduce the processing overhead by setting the valid number of pieces of information at the value equal to or larger than the multiplex degree of a system element. CONSTITUTION:The processors 1a - 1c are prepared as the process executing means where the system elements are registered together with the message identifying means 2a - 2c which identify the same messages connected to the processors 1a - 1c, and the message exchanging devices 3a - 3c. These processors, means and devices are connected in series. When the information are exchanged among the multiplexed system elements A - C, each system element validates a message when it receives the information of the same contents from a group of multiplexed elements in the number of valid pieces. Thus it is not required to wait for the messages to be received from all multiplexed system elements. Then the processing overhead is reduced.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a system in which system elements such as programs and resources are multiplexed for the purpose of improving reliability. The present invention relates to a parallel multiplex control method that efficiently extracts the correct message from among the messages sent by the system, without individual system elements being aware of the multiplicity and with less processing overhead.

(Prior art) In recent years, with the multiplexing of elements in various fields of computer systems and the advancement of technology, systems have tended to become larger and more complex.
Demand for distributed processing systems is increasing.

At this time, in order to improve the reliability of the system, we have adopted a parallel multiprocessing method in which the same process is executed in parallel by multiple system elements, and a process is executed in the tp- system element, so that if the system element being executed fails, A standby redundant processing method in which the spare element continues processing at a stage.In the standby redundant processing method, it takes time for the spare element to take over processing especially when there is a failure, or to take over processing at a high speed, the spare element is frequently interrupted in the middle of processing. There are drawbacks such as the need to report progress. For this reason, in real-time control systems and the like, the parallel multiprocessing method is preferable, but the parallel multiprocessing method requires a mechanism for extracting the correct message from messages received from a group of elements in which individual elements are multiplexed.

Having complete self-diagnostic capabilities to ensure that each system element receives only the correct messages will ensure that each system element only outputs the correct messages, so that each system element adopts the first message it receives. By using a first-come, first-served priority processing method that ignores messages that arrive after , the correct message can be received.

However, since it is difficult to realize a sophisticated self-diagnosis function, a method of comparing messages from multiplexed system element groups is generally used. In a method that compares messages from a group of multiplexed system elements, the correct message is usually extracted by majority vote, but in order to do this, each system element needs to know the multiplicity of related system elements, which makes it difficult to expand the system. It was hindering me. Additionally, there was a large overhead during processing, such as having to wait for the number of messages required for majority voting to arrive.

Therefore, it is important to have a multiprocessing control method that minimizes processing overhead and downtime due to failures during system execution, and does not take into account the multiplicity of related system elements.

(Problem to be Solved by the Invention) In the conventional method of comparing messages of multiplexed system element groups described above, the correct message is usually extracted by majority vote. There was a problem in that it was necessary to know the multiplicity, which hindered the expandability of the system.

Another drawback is that there is a large overhead during processing, such as having to wait for the number of messages required for majority voting to arrive.

The present invention has been made in response to these circumstances, and aims to minimize the overhead of processing between multiple element groups, making it applicable to real-time control, and eliminating the need to be aware of the degree of multiplicity of related elements. The aim is to achieve high reliability without compromising system scalability.

[Structure of the Invention] (Means for Solving the Problems) The parallel multiplex control system of the present invention that achieves the above-mentioned conventional object includes at least one message exchange means, and a method for identifying and classifying received messages according to the same content. a message identification means for registering multiplexed system elements;
In a parallel/distributed processing system that combines processing means that execute its functions, when exchanging information between multiplexed system elements, each system element receives predetermined information of the same content from a group of multiplexed elements. The present invention is characterized in that when a valid number of messages is received, the message is validated.

(Function) In the present invention, the effective number is equal to or less than the multiplicity of the corresponding system element.

As a result, each system element only needs to know the reliability (valid number of messages) required for the associated system element (this value can also be added to the message) and the multiplicity of the associated system element. Multiplexing system elements does not reduce scalability or adaptability because it is not necessary.

Furthermore, by setting the effective number to :J3, it becomes possible to arbitrarily set the reliability of the message content. Furthermore, unlike the majority voting system, there is no need to wait for messages from all related elements, so processing overhead can be kept low.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a parallel multiplex control system according to an embodiment of the present invention.

The parallel multiplex control method of this embodiment uses processors 1a, lb, and lc as processing execution means in which system elements are registered.
and message identification means 2a, 2 for identifying the same message connected to the processors la, lb, lc, respectively.
b, 2c and message exchange devices 3a, 3b, 3c are connected in a line. Here, processor 1
a, 1b, lc perform the functions of the system elements,
Messages generated by the system elements are transmitted via message exchange devices 3a, 3b, 3c. The transmitted message is sent to the message exchange devices 3a, 3b,
3c, the message identification means 2a, 2b
, 2c, and are classified into messages with the same content.

In the present invention, for reasons such as improving reliability, the individual system elements are multiplexed, as shown in FIG.

They are distributed and arranged in the IC. In FIG. 2, system elements A and C are registered with processors la, lb and IC, and system element B is registered with processors 1a and 1b. Under these circumstances, each system element A,
B and C execute processing while exchanging messages between different system elements as shown in FIG. 3, but at this time, each system element is not aware of the multiplicity of other system elements including its own element.

In FIG. 3, system element A is element Al.

A2. Tripled with A3, system element B is element B1, B
2, system element C is element C1゜C2, C3
It is triplexed. Each multiplexed system element group is designed to perform the same processing.

Further, the effective number of messages is declared in advance for each system element. This effective number shall be equal to or less than the multiplicity of the corresponding system element. For example, assume that the effective number of messages issued by system element A is 2, and the effective number of messages issued by system element B is 1. Each system element transmits a message using broadcast communication without being aware of which processor the destination system element resides in or how many layers it has. Under such circumstances, system elements Al, A2 and A3 transmit their processing results to system element B. The system element 81□B2 performs message reception processing according to the flowchart in FIG.

Messages sent by individual system elements A are received by the message switching device (step 401).
), and the received messages are classified by message identification means into messages having the same content (step 4).
02), 1 is added to the number of times the message has been received (step 403), and the number of times the message has been received is compared with a previously declared valid number (step 404). For example, if the message is from system element A, the effective number is 2, so if the number of receptions is less than 2, the received message is saved (step 405), and when the number of receptions is equal to 2 (
In other words, when the number of receptions reaches 2), the message is validated (step 406), and the message is passed to the destination system element (step 407).

When the number of receptions is greater than the valid number (that is, when the number of receptions is greater than 2), the received message is discarded (step 408). In the case of FIG. 3, when each system element Bl, B2 receives a message with the same content from any two of A1, A2, or A3, the message is validated and each system element Bl, B2 is activated. . 3
If another message with the same content is received, that message will be discarded.

Since the effective number of messages from system element B is declared to be 1, each system element C1, C2,
C3 converts messages sent from system elements B1 and B2 that arrive earlier to the right, and discards messages that arrive later.

As a result, according to this embodiment, each system element only needs to know the effective number as the reliability required for the related system elements, and there is no need to know the multiplicity of the related system elements. This does not reduce scalability or adaptability. Furthermore, by adjusting the effective number, it is possible to arbitrarily set the reliability of the message content. Furthermore, unlike the majority voting system, there is no need to wait for messages from all related elements, so processing overhead can be kept low.

[Effects of the Invention] As explained above, according to the parallel multiplex control method of the present invention, each system element does not need to be aware of its multiplicity;
It is sufficient to declare in advance only the effective number that indicates the reliability of the message.

Therefore, there is no need to consider the multiplicity of system elements when expanding the system, and expandability can be improved.

Additionally, since there is no need to wait for messages from all multiplex system elements, processing overhead can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram showing a state in which multiplexed system elements are distributed among processors, and FIG. 3 is a diagram showing how multiplexed system elements are distributed among processors. FIG. 4 is a flowchart showing the operation when a message is received. la, yu b, 1cm processor, 2a, 2b2
c=--Message identification device, 3a, 3b, 3cm message exchange device, A, B, C... System elements.

Claims (1)

[Claims] A parallel system comprising at least one message exchange means and a message identification means for identifying and classifying received messages according to the same content, and combining processing means in which multiplexed system elements are registered and their functions are executed. /In a distributed processing system, when information is exchanged between multiplexed system elements, when each system element receives a predetermined effective number of pieces of information with the same content from a group of multiplexed elements,
A parallel multiplex control method characterized by activating the message.