JPH0126093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a slowdown control method that is effective in making effective use of resources in a computer system.

Prior Art and Problems In large-scale computer systems, various messages are exchanged during program execution.
This involves securing a memory area, storing the received message in the area, and then reading it from the area and passing it on. For example, in a computer system consisting of a host, a terminal controller (TC), and a terminal device, a message is passed from the host to the TC, which is then passed to the terminal, and conversely, a message (data) is passed from the terminal to the TC, which is then passed to the host. However, at this time, the
The message or data is temporarily stored in the TC buffer. Since messages are generated as a program is executed, a memory area is secured before the program is run (during system generation) to ensure that messages generated during program execution can be stored and sent. It is better to secure a wider memory area to avoid problems such as not being able to store all messages, but if you allocate too much memory, computer resources such as memory and buffers will be left idle, which is a problem in terms of effective resource utilization. That's a problem.

Therefore, a suitable memory area is secured and the program is started, but if the number of messages during execution of the program is large and requires more resources than planned, the conventional method cannot handle it. Therefore, the system goes down, the program stops running, and the CPU stops working. There is also a method that returns a busy signal and does not accept messages (prohibits message sending). In the former case, from the perspective of the input/output device, the host device will stop operating, so there is no choice but to suspend the operation until the function is restored, which will hinder processing. In the latter case, it is a kind of slowdown control (control to reduce processing speed), but from the perspective of the input/output device, the request is bounced back and the request has to be raised again, making the operation cumbersome.

OBJECTS OF THE INVENTION The present invention aims to provide a slowdown control method that requires relatively few resources to be secured, can therefore be used effectively, and does not cause system downtime or busyness.

Composition of the Invention The present invention is a slowdown control method for a computer system that starts program execution after securing resources used for message exchange in advance, and stores the used resource number and number of resources for each process number given to each program. 1st
and a second table that stores each resource number and the number of remaining resources, and when there is an input, it is determined whether or not the resources necessary to execute the processing program for the input are secured in the first and second tables. If the input is not reserved, a queue is created for the input and the slowdown flag is turned on. When the input is interrupted, the slowdown flag is checked and if it is on, the first The present invention is characterized in that it refers to the second table to check whether there is an input that can be executed in the queue, and moves on to executing the input.This will be described in detail below with reference to an embodiment.

Embodiment of the Invention The drawing shows the main parts of the terminal controller TC of the above-mentioned computer system consisting of a host, TC, and terminal, that is, the parts related to the present invention, where 10 is a program control part, PA is a program A, and SP is a slowdown part. In the control program, TBL1 and 2 indicate tables 1 and 2, and WQ indicates a queue. Also, the ones with diagonal lines attached to them indicate cells for communication between programs.

When there is an input (request) to the program from the host or terminal, the program control unit 1
At 0, it is determined to which program control should be given (dispatch control). Programs are divided into types such as those for processing input from the host and processing input from a terminal (they are structured programs), and if the input is from the host, control is passed to the program in question. If control is now passed to program A, that program will perform initial processing and first refer to Table 1 to find the resource number and number of resources necessary for its own processing. All programs are assigned a number, that is, a process number.
Index Table 1 using this number. Resources (memory areas in this case) are also numbered.
There are multiple resources with the same number, or each resource distinguished by resource number is composed of multiple categories. Program A is its own process
After indexing Table 1 using the number and obtaining, for example, resource No. 3 and the required number of resources 3, next indexing Table 2 using the resource number to find the number of free resources for the resource No. 3. In this example, this is 4, and since the required number of resources is 3, the program can be executed. In this case, the process moves to step 1 and enters the main process.

Resource No.1, like process No.2 program
If the required number of resources is 4, the remaining number of resources is 3 as shown in the figure, so the number of resources is insufficient. In this case, step is entered and control is passed to the slowdown control program (in the communication cell). The slowdown control program puts the cell in queue WQ and turns on the slowdown flag,
It indicates that a queue has been created or that there is a queue, and then control is returned to the program control unit 10 to wait for the next input. When control is passed, the program control unit 10 processes the next input. This input is the resource number that created the queue. In this example, 3
and free resources
If the message is to be flushed out from resource No. 1 in this example, it will be executed immediately, and if it is to use resource No. 1, it will be executed in queue Q. Perform processing such as adding. If the process of sweeping out messages from resource No. 1 is performed, the resource No. 1 becomes vacant.
If there is no input and the slowdown flag is on, program control section 10 passes control to the slowdown control section. The slowdown control unit refers to Tables 1 and 2 according to each cell in the queue Q, and if there is a cell in which the number of remaining resources is greater than the number of required resources, control is passed to the program A in this example. In this case, control is returned to the program control unit 10. When control is passed to program A, the program enters the main process in the same way as when execution is started using the route (however, initial processing is not necessary).

The number of remaining resources in table 2 is constantly updated, and this update is performed by program control unit 10. Table 1 is fixed, defined at the time of system design, and modified if changes occur. In the figure, each process number is shown to use only one type of resource number, but of course, multiple resource numbers may be used, and in this case, the corresponding process number column in Table 1 is Multiple resource numbers are listed along with the required number of resources.

It is possible to create a queue for each resource, but it is possible to create a queue for each resource, but it is possible to create a queue for each resource.
If there are many numbers, control becomes difficult.
In this regard, control is easier if a queue is created for each input (request) as in the present invention, and the execution and queue are distinguished depending on whether all the resources necessary for processing the input are secured.

Effects of the Invention As explained above, according to the present invention, when there is an input, it is checked whether the resources necessary to process the input can be secured, and if the resources cannot be secured, the input is placed in a queue and the resources are freed. Since the system waits, it is not necessary to secure excessive resources, and therefore resources can be used effectively, and there is no need for re-input, so there are advantages such as ease of operation.

[Brief explanation of drawings]

The drawing is a block diagram showing an embodiment of the invention. In the figure, TBL1 is the first table and TBL2 is the second table.
In the table, WQ is a queue, 10 is a program control unit, and SP is a slowdown control program.

Claims (1)

[Claims] 1. In a slowdown control method for a computer system that starts program execution after securing resources used for message delivery in advance, the used resource number and number of resources are stored for each process number given to each program. A first table that stores each resource number and the number of remaining resources is prepared, and when there is an input, it is determined whether or not the resources necessary to execute the processing program of the input are secured. If the second table is not reserved, create a queue for the input and turn on the slowdown flag, and when the input is interrupted, check the slowdown flag and if it is on, use the above again. A slowdown control method characterized by referring to first and second tables to check whether there is an input that can be executed in a queue, and then proceeding to execute the input.