JPH0372741A - Polling system - Google Patents

Abstract

PURPOSE:To attain smooth system operation by suppressing the accept of a service request to a terminal equipment whose number of unprocessed accepts exceeds a prescribed number with the revision of the polling priority and the stop of polling. CONSTITUTION:A monitor section 13 monitors the number of unprocessed accepts of a service (representing the frequency of occurrence of service requests) for each terminal equipment 4 and revises the polling priority of the terminal equipment when the number reaches a 1st prescribed number (e.g. set to a predict frequency of occurrence of service requests). When the number reaches a 2nd prescribed number (limit of the system processing capability) in excess of the 1st prescribed number, the monitor section 13 stops the polling to the terminal equipment 4. Thus, even when requests are concentrated on a terminal equipment unexpectedly, the service performance of subsequent terminal equipment is not deteriorated, and an operation-down of one terminal equipment does not result in the system-down, then the smooth system operation is attained.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a polling method, and aims to ensure smooth system operation by suppressing the acceptance of service requests to terminals exceeding the expected frequency. In a data processing device that polls service requests output from a terminal in a predetermined priority order and accepts the service requests, and sequentially extracts the accepted service requests and executes a predetermined process, the unprocessed service requests are processed. The number of receptions is monitored for each terminal, and the polling priority for terminals exceeding a first predetermined number is changed to the lowest, and polling is stopped for terminals exceeding a second predetermined number, and unprocessed receptions are A monitoring unit is provided that returns to a predetermined priority order when the number of unprocessed receptions recovers to the predetermined number or less, and changes the polling priority order and polls the reception of service requests for the terminal for which the number of unprocessed receptions exceeds the predetermined number. Configure to suppress by stopping.

[Industrial application field]

The present invention relates to improvements in polling methods.

There are many different configurations of polling systems, but
In a system that connects multiple terminals in a multi-drop connection (1-to-N connection) and provides multipoint service in response to service requests from the terminals, if the number of service requests generated from one terminal is higher than expected, the service requests for other terminals will be There is a problem that the service will deteriorate, and if one terminal goes down and keeps issuing requests, the system will go down.

Therefore, there is a need for a polling method that solves the above operational problems in such a polling system.

[Conventional technology]

Figure 5 is a configuration diagram of a conventional polling system.
An example of a polling system using a B interface adapter (hereinafter referred to as an adapter) is shown.

The adapter 2 and the plurality of terminals 4 are multi-drop connected by GPIB, and the terminal 4 that has generated a service request such as data transfer or status notification outputs the service request to a request line that is connected in an instantaneous manner or wired or connected.

The adapter 2, which has recognized the service request from the terminal 4, polls according to the priority order specified in the polling table 9, and receives the details of the service request (
Status information) is received and stored in the status buffer, and if there is a status buffer waiting to be processed, it is linked to the next status buffer.

Note that polling is not performed cyclically, but polling is performed from the top of the priority order for each requested output.

The contents of the status buffer received in this way are
The information is sequentially taken out by a higher-level interface control unit (not shown) provided separately in the adapter 2, and transferred to the main control unit 1 for processing.

[Problem to be solved by the invention]

In a polling system that provides multipoint services with a multidrop connection configuration, each terminal is polled in accordance with a predetermined priority order for service request outputs, and service requests are accepted.

Therefore, as mentioned above, each request output is polled from the higher-level side, so if a certain terminal receives more service requests than expected, the reception of service requests from lower priority terminals will be much later than expected. , which impedes smooth system operation.

Furthermore, if a certain terminal goes down and keeps issuing requests, the number of polling increases and the reception buffer becomes full, which may cause the system to go down.

An object of the present invention is to provide a polling method that solves the above problems.

[Means to solve the problem]

In order to achieve the above object, the polling method of the present invention is as follows:
As shown in FIG. 1, a diagram of the principle of the present invention, the number of unprocessed accepted service requests is monitored for each terminal 4, and the polling priority for terminals exceeding a first predetermined number is changed to the lowest,
A monitoring unit 13 is provided which stops polling for terminals exceeding a second predetermined number and returns them to predetermined priorities when the number of unprocessed receptions recovers to below the predetermined number.

[For production]

(1) The monitoring unit 13 monitors the number of unprocessed receptions of service requests (representing the frequency of occurrence of service requests, hereinafter referred to as the number of receptions) for each terminal 4, and monitors the number of unprocessed receptions of service requests (representing the frequency of occurrence of service requests, hereinafter referred to as the number of receptions) for each terminal 4, and setting), the polling priority of that terminal is changed to the lowest.

As a result, the priority level of the terminal 4, which has conventionally been on the lower side, becomes higher, and service requests can be accepted preferentially.

Further, when a second predetermined number (limit value of system processing capacity) exceeding the first predetermined number is reached, the monitoring unit 13
Stop polling for.

As a result, reception of service requests to terminals 4 is stopped, thereby avoiding a system down due to a failure of one terminal.

Note that when the number of receptions for the terminal 4 is restored to below the first or second predetermined number through the process, the respective predetermined priorities are restored.

(2) Providing a reception buffer (status buffer) for each terminal makes it easier to monitor the number of receptions.

〔Example〕

Embodiments of the present invention will be described in detail with reference to the drawings.

In this embodiment, a terminal-compatible reception buffer (status buffer 14 in Figure 2) is provided, and depending on the number of buffers that store status information that is a response to polling,
An example of monitoring the number of receptions is shown.

Figure 2 is a block diagram of the polling system of the embodiment;
4 is a flowchart of the operation of the polling control section, and FIG. 4 is a flowchart of the operation of the monitoring section. In FIG. 2, reference numeral 9 denotes a polling table, in which a predetermined priority is set in the initial setting, and the monitoring unit 13 changes the setting of whether polling is necessary or not and changes the priority.

A polling control unit 11 refers to the polling table 9 when a service request is output, polls the terminals 4 that require polling in the priority order specified by the terminal 4, and stores the received status information in the status buffer 14.

A monitoring unit 13 monitors the status buffer 14 and changes the priority order and sets polling necessity/unnecessity in the polling table 9 according to the number of buffers storing status information (number of receptions).

14 is a status buffer, and the buffer storing the received status information corresponds to each terminal (terminal ^, B,
Status buffers 14-A and B for C.

It is linked in C).

In addition, the adapter 2 includes a transfer control section 7 that controls data transfer between the main memory 5 and the terminal 4. It is composed of an upper IF control section 6 that extracts status information from the status buffer 14 and passes it to the main control section 1, and a lower IF control section 12 that exchanges data with the terminal 4. Note that the same reference numerals represent the same objects throughout the figures.

Polling control shown in the following example is performed by the adapter 2 having the above configuration.

(1) Polling control unit operation (see Figure 3) When a service request is generated from the terminal 4, the polling control unit 11
For each requested output, polling is performed sequentially in priority order based on the polling table 9, and the terminal 4 that has made the requested output sends status information in response to the polling.

The polling control unit 11 stores the received status information in a buffer, identifies the terminal 4, and links it to the corresponding status buffer 14.

(2) Operation of the monitoring unit (see FIG. 4) On the other hand, the monitoring unit 13 monitors each status buffer 14 periodically or upon receiving a polling response or taking out status information, and monitors each status buffer 14 from among the status buffers 14. If there are status buffers 14 that have reached a predetermined number, the polling table 9 is changed to change the priority of that terminal to the lowest.

Further, if there are status buffers 14 that have reached a second predetermined number, the polling table 9 is set to indicate that polling is not necessary for that terminal 4.

The number of receptions is reduced by the extraction of status information by the upper IF control unit 6 and the execution of processing by the main control unit 1, and when it becomes less than the first or second predetermined number, the priority order is returned to the original priority order.

That is, depending on the number of receptions for each terminal 4 stored in the status buffer 14, ■Number of receptions (if the first predetermined number, the initial setting priority, ■Second predetermined number>Number of receptions ≧ first predetermined number) If so, the priority is the lowest, ■If the number of receptions≧the second predetermined number, polling is stopped, and the terminal 4 corresponding to 0 is set.

As a result of the above, when the number of requests reaches the first predetermined number, the priority of the terminal 4 is changed to the lowest, and when the number reaches the second predetermined number, polling is stopped. The priority level of the terminal 4 that was lower than that terminal 4 becomes higher, and the delay in reception on the lower level side is eliminated.

In addition, terminal 4, which has not issued a service request due to a failure,
If there is, polling will remain stopped, which will prevent the system from going down.

In the above embodiment, an example was shown in which the status buffer 14 is provided corresponding to each terminal to monitor the number of receptions for each, but a counter that is added or subtracted depending on reception and retrieval may also be provided corresponding to the terminal.

〔Effect of the invention〕

The present invention monitors the number of accepted service requests for each terminal,
When the number of unprocessed receptions exceeds a predetermined number, it provides a polling method that suppresses the reception of requests from that terminal by lowering the polling priority or stopping polling. In a multipoint service polling system, even if requests are unexpectedly biased toward a certain terminal, the service performance of lower-level terminals does not deteriorate, and the failure of one terminal does not lead to system failure, which has great effects on system operation.

[Brief Description of the Drawings] Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a block diagram of a polling system according to an embodiment, Fig. 3 is a flowchart of the operation of the polling control unit, Fig. 4 is a flowchart of the operation of the monitoring unit, FIG. 5 is a configuration diagram of a conventional polling system. In the figure, 1 is the main control unit, 2 is the adapter, 4 is the terminal, 5 is the main memory, 6 is the upper IF control unit, 7 is the transfer control unit, 9 is the polling table, 11 is the polling control unit, and 12 is the lower IP Control unit, 13 is a monitoring unit, 14 is a step 1 2

Claims (2)

[Claims] (1) Data that polls service requests output from multiple multi-drop connected terminals in a predetermined priority order, accepts the service requests, and sequentially extracts the accepted service requests and executes a predetermined process. The processing device monitors the number of unprocessed receptions of the service requests for each terminal (4), changes the polling priority for terminals exceeding a first predetermined number to the lowest, and changes the polling priority for terminals exceeding a second predetermined number to the lowest. A monitoring unit (13) is provided to stop polling for the respective unprocessed receptions, and to return to the respective predetermined priorities when the number of unprocessed receptions recovers to below the predetermined number, and when the number of unprocessed receptions reaches the predetermined number. A polling method characterized by suppressing acceptance of service requests for a terminal that exceeds the number by changing polling priorities and stopping polling. (2) The polling method according to claim (1), wherein a buffer for receiving service requests is provided for each terminal, and the monitoring unit monitors and suppresses the number of requests received based on the buffer.