JP3260399B2 - Asynchronous I / O dynamic priority change method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data processing system, and more particularly to a method for controlling the timing of asynchronous I / O processing in a system.

[0002]

2. Description of the Related Art Generally, a data processing system of this type includes an external storage device in addition to a main storage device, and uses a part of the main storage device as an asynchronous I / O buffer for the external storage device. There is. In this case, data is written to or read from the asynchronous I / O buffer of data under the control of a control program that sends and receives various requests and data to and from the user program. ing.

When a write request is issued from a user program, data is written from an asynchronous I / O buffer to an external storage device irrespective of the data usage rate or the like. As described above, in the data processing system that accesses the external storage device by the conventional asynchronous I / O method, the I / O operation to the external storage device is performed without considering the priority between data.

[0004]

In other words, in the data processing system for accessing the external storage device by the asynchronous I / O method as described above, the I / O to the external storage device is not performed.
O is an asynchronous I / O execution task having a unique priority, and the I / O is being executed. Therefore, the data is reused and the optimal I / O access to the external storage device is performed in the asynchronous I / O buffer in the system. Does not consider the efficiency of data manipulation. For example, when a data read request is issued from a user program, the corresponding data is not found, and there is a problem that data is read from the external storage device again. Therefore, a technical problem of the present invention is that the main storage device can be used effectively,
It is an object of the present invention to provide an asynchronous I / O dynamic priority change method capable of shortening the time for reading and writing data from a user program and dramatically improving the data processing speed.

[0005]

According to the present invention, an external storage device and a main storage device are provided, and a part of the main storage device is used as an asynchronous I / O buffer for the external storage device. In a data processing system that performs an asynchronous I / O operation from a main storage space to the external storage device by using an asynchronous I / O execution task, a control program that stores data in a buffer and the asynchronous I / O execution task
A priority control means for controlling the priority of the O execution task; and an asynchronous I / O buffer based on the utilization rate of the asynchronous I / O buffer under the priority control means.
Means for dynamically changing the priority of the I / O execution task.
A dynamic priority change method is obtained.

According to the present invention, the priority control means updates the count in response to each data write request from the asynchronous I / O execution task and the control program, thereby controlling the use of data in the buffer. An asynchronous I / O dynamic priority change, comprising: an asynchronous I / O data counter for calculating a rate; and a priority control table for controlling the priority of the asynchronous I / O execution task in accordance with the contents of the counter. A scheme is obtained.

[0007]

[0008]

In the present invention, a part of the main storage device is used as an asynchronous I / O buffer for the external storage device. The control program stores data in this buffer. On the other hand, the asynchronous I / O execution task performs an asynchronous I / O operation on data in the buffer from the main storage space to the external storage device. The priority of the asynchronous I / O execution task is controlled by priority control means, and the priority is changed by means of priority change under the priority control means.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. As shown in FIG. 1, the data processing system includes a control program 10, an asynchronous I / O execution task 20, a priority control table 6, an asynchronous I / O data counter 7, and a part of the main storage space of an asynchronous I / O. It comprises a main storage device 4 used as the O buffer 3 and an external storage device 5.

FIG. 2 is a flowchart of a processing example of the asynchronous I / O execution task 20 shown in FIG.

Referring to FIG. 2, the operation of the embodiment shown in FIG. 1 will now be described. The control program 10 executes an asynchronous I / O in accordance with an input / output request from a user program 00.
Data input 1 and output 2 are performed in the buffer 3, and data is exchanged with the user program 00. At the time of this data input 1, the asynchronous I / O data counter 7 is updated.

The asynchronous I / O execution task 20 writes the data in the external storage device 5 until the data in the asynchronous I / O buffer 3 is exhausted separately from the user program 00. At this time, the asynchronous I / O data counter 7 is updated (S
6).

More specifically, as shown in FIG.
The O execution task 20 becomes ready when valid data is generated in the asynchronous I / O buffer 3, and
External storage device 5 until there is no more data in O-buffer 3
Data is written to (S5, S7). The asynchronous I / O execution task 20 performing this process changes the priority using the asynchronous I / O data counter 7 and the priority control table (S1, S2, S3).

The asynchronous I / O execution task 20 operates separately from the user program 00 and the control program 10, and dynamically changes the priority based on the usage rate of the asynchronous I / O buffer (S6). At this time, the priority applicable to the buffer usage rate is searched from the priority control table 6 (S3).

In connection with the above, since data is exchanged between the user program 00 and the control program 10, when the data write request is issued from the user program 00, the control program 10
Stores the data in the asynchronous I / O buffer 3, sets the asynchronous I / O execution task 20 to the ready state, and continues data exchange with the previous user program. on the other hand,
The asynchronous I / O execution task 20 is brought into the ready state by the control program 10 and the asynchronous I / O buffer 3
The writing process is continued until the valid data in the external storage device 5 has no valid data. However, in order to perform this write processing at the optimum timing in the system, the asynchronous I / O execution task 20 and the control program 10 manage a counter for calculating the usage rate of the asynchronous I / O buffer, and thus the priority control table is managed. Is used to control the priority of the asynchronous I / O execution task 20.

[0017]

According to the present invention as described above,
When a write request occurs, the data is stored in the asynchronous I / O buffer, and the actual writing is performed by a separate task. At this time, in order for the system to make effective use of the data in the asynchronous I / O buffer, , Asynchronous I /
The priority of the asynchronous I / O execution task is controlled based on the usage rate of the O-buffer, and is dynamically changed so that writing to the external storage device is performed. By making appropriate access to the main storage, the main storage can be used effectively, reducing the time required to read and write data from the user program, and dramatically improving the processing speed of the data processing system. As a result, an asynchronous I / O dynamic priority change method can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart of a processing example of an asynchronous I / O execution task in FIG. 1;

[Explanation of symbols]

 1 Input 2 Output 3 Asynchronous I / O Buffer 4 Main Storage 5 External Storage 6 Priority Control Table 7 Asynchronous I / O Data Counter 00 User Program 10 Control Program 20 Asynchronous I / O Execution Task

Claims (1)

(57) [Claims] An external storage device and a main storage device are provided, and a part of the main storage device is used as an asynchronous I / O for the external storage device.
Use as a buffer, and a control program to store data in the asynchronous I / O buffer, the asynchronous I / O
In a data processing system in which data in a buffer is subjected to an asynchronous I / O operation from a main storage space to an external storage device by an asynchronous I / O execution task, the asynchronous I / O execution task and the control program
The count is updated in response to these data write requests
Asynchronous I / O data counter and corresponds to the count of the asynchronous I / O data counter
Usage rate of the asynchronous I / O buffer and the asynchronous I / O
A program that stores execution task priorities in association with each other.
A priority control table, the asynchronous I / O counter, and the priority control table.
Asynchronous I / O dynamic priority change method referring to the Buru determines the priority of the asynchronous I / O execution task, is characterized in that a priority control means for dynamically changing.