JPH03100752A - Holding type input/output control system - Google Patents

Abstract

PURPOSE:To prevent the input/output request having a high priority level from waiting by temporarily holding the already started input/output operation at the time of the occurrence of the input/output request having a high priority of processing and preferentially executing the input/output request. CONSTITUTION:Two device addresses, namely, a device address 7a for high- speed access and a device address 7b for low-speed access are prepared for one input/output device 2; and if the input/output device 2 already starts the input/output operation by the device address 7b for low-speed access at the time of the occurrence of an input/output request to the device address 7a for high-speed, the input/output operation executed at present is temporarily held on the input/output operation executed at present is temporarily held on the input/output device 2 side. Then, the input/output request to the device address 7a for high-speed access is preferentially executed, and the held input/ output operation of the device address 7b for low-speed access is restarted at the time of the end of the input/output operation. Thus, the processing of the input/output request to the device address for high-speed access is not kept waiting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pending input/output control method, and in particular, in a data processing system, input/output control is performed when a process that requires high response, such as online processing, is issued. The output request is
The present invention relates to a pending input/output control method that prevents long waiting times due to input/output requests that handle large amounts of data issued to the same input/output device.

[Conventional technology]

Conventionally, in data processing systems, a control program (input/output supervisor) that manages input/output devices creates a device management table for each input/output device.
Create each input/output request for each input/output device and register it as an element of the queue according to the priority of each input/output request.
When the channel and the corresponding I/O device become available, processing begins at the head of the queue and each I/O request is processed.

FIG. 3 is a block diagram illustrating the processing of an input/output supervisor that processes input/output requests.

In FIG. 3, 31 is a central processing unit, 32 is an input/output supervisor, 33 is an input/output request queue, 34 is a device management table, 35 is a magnetic disk controller, and 36 is a magnetic disk device.

Magnetic disk family from processing program not shown! ! 36
When an input/output request for an input/output device such as
The issued input/output requests are registered in the input/output queue 33 as elements of the queue according to the priority of each input/output request. As a result, each input/output request 40, 41, 42 is registered in the input/output queue 33 according to the priority order, and the input/output request processing is scheduled. Then, when channels and input/output devices become available, input/output requests are sequentially taken out from the head of the input/output queue 33, and
Processing of each input/output request is performed by, for example, sending an access bus ( channel path) and perform input/output processing.

[Problem to be solved by the invention]

By the way, when the input/output supervisor 32 schedules input/output processing using the input/output queue 33 and processes input/output requests as described above, the input/output requests are not made to input/output devices that are already in operation. If the
Even if the processing priority of the input/output request is high, the input/output request will only be scheduled, and the processing of the input/output request will have to wait until the active input/output processing is completed.0For example, In a data processing system, when input/output requests that handle large amounts of data are being processed for one input/output device, processing that requires high response, such as online processing, is prioritized. Even if the input/output request is high, the user will have to wait for a long time due to the processing of the input/output request that handles a large amount of data and is being executed for the same input/output device.

In this way, no consideration has been given to suspending the input/output operation being executed for the input/output device that is already in operation, and having the input/output request with a higher processing priority executed first. For input/output processing that is currently being executed, no matter how high the priority of the processing is, the input/output request will not be processed until the input/output operation is completed.

There is a problem in that the processing of the input/output request is made to wait.

The present invention has been made to solve the above problems.

It is an object of the present invention to realize that an input/output request issued from a process that requires a high response such as online processing in a data processing system can be used as an input/output request that handles a large amount of data issued to the same input/output device. An object of the present invention is to provide a hold-type input/output control method that prevents the input/output from being delayed for a long time.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

In order to achieve the above object, the pending input/output control method of the present invention prepares a plurality of device addresses with different processing priorities for the same input/output device, and outputs a device address by specifying the device address. In response to an input/output request, the same input/output device is already performing input/output operations at a lower priority device address.

The I/O operation being executed at a device address with a lower priority is temporarily suspended on the I/O device side, the I/O request issued at a device address with a higher priority is executed first, and that I/O operation is completed. It is characterized in that, at the point in time, the pending input/output operation of a device address with a lower priority is restarted.

[Effect]

According to the above-described means, a plurality of device addresses with different processing priorities are prepared for the same input/output device, for example, two device addresses, a high-speed access device address and a low-speed access device address. Ru. Processing of an input/output request issued to a high-speed access device address is executed using the low-speed access device address if the same input/output device is already performing input/output operations using the low-speed access device address. The input/output operations during the process are temporarily suspended on the input/output device side, and the input/output requests issued to the high-speed access device address are executed in advance. Then, when the input/output operation of the input/output request issued to the high-speed access device address is completed, the input/output operation of the pending low-speed access device address is restarted.

For example, an input/output device that is provided with two device addresses, a high-speed access device address and a low-speed access device address, will process the input/output request no matter which device address is used to perform the input/output request. When input/output requests are received at the same time for both a high-speed access device address and a low-speed access device address, the input/output request for the high-speed access device address is executed first. and,
After the input/output operation of the input/output request at the high-speed access device address is completed, the input/output operation at the low-speed access device address is started.

In addition, if an input/output request is already being executed at a low-speed access device address when an input/output operation execution request is accepted at a high-speed access device address, the input/output operation execution request at the low-speed access device address is already being executed. suspends input/output operations,
The I/O operation for the I/O request received using the high-speed access device address is executed first, and after the I/O operation is completed, the I/O operation for the low-speed access device address that was on hold is restarted. do.

As a result, processing of an input/output request issued using a high-speed access device address is not made to wait for execution of an input/output request issued using a low-speed access device address.

In this way, a plurality of device addresses with different processing priorities are provided for the same input/output device, for example, two device addresses are provided, a device address for high-speed access and a device address for low-speed access, Even if an input/output request is already being processed for an input/output device, if an input/output request occurs at a device address with a higher processing priority than that input/output request, the input/output request that is already being processed will be processed. The output operation is held for a while, the input/output request of a higher priority device address that occurs later is executed first, and the suspended input/output request is restarted when the input/output operation is completed. This prevents high-priority input/output requests from having to wait for processing of other input/output requests.

When an input/output request is made using a device address for high-speed access, the input/output processing is for high-speed, small-volume processing, such as online processing, and when an input/output request is made using a device address for low-speed access, for example.

This is input/output processing for low-speed, high-volume processing, such as database processing. This allows input/output requests issued from processes that require high response, such as online processing in data processing systems.

This prevents the device from being open for a long time due to input/output requests that handle large amounts of data issued to the same input/output device.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described using the drawings.

FIG. 1 is a block diagram showing the configuration of essential parts of a data processing system that schedules and executes processing of input/output requests according to an embodiment of the present invention.

In FIG. 1, 1 is a central processing unit, 2 is an input/output supervisor, 3a, 3b are input/output request queues, 4a, 4b
1 is a device management table, 5a and 5b are magnetic disk control devices, and 6 is a magnetic disk device having a processing hold function. In addition to the magnetic disk device section 13, the magnetic disk device 6 has a function of suspending and processing input/output requests with different processing priorities, so the priority processing control section 11 and the input/output request suspension processing section 12 are provided. Be prepared. Furthermore, two device addresses are set in the magnetic disk device 6: a high-speed access device address 7a and a low-speed access device address 7b, which are device addresses with different processing priorities. You can also use it to make input/output requests. In addition, 14.15
．． 16.17 shows each input/output request registered in the queue.

The magnetic disk device 6, which has two device addresses, has a different magnetic disk control device for each device address! 5a
, 5b to a channel (not shown) of the central processing device 1. The input/output supervisor 2 that manages the input/output devices creates device management tables 4a and 4b corresponding to each device address of the input/output devices, registers the device addresses, and schedules processing of input/output requests. .

In this example, device management tables 4a and 4b are created for a magnetic disk device 6 that has two device addresses, a device address for high-speed access 7a and a device address for low-speed access 7b, and the device management tables 4a and 4b are created for each device management table 4.
A high-speed access device address 7a and a low-speed access device address 7b are registered in a and 4b.

The device address (
The high-speed access device address 7a) is.

The device address (
The processing priority is set higher than the low-speed access device address 7b). When using the magnetic disk device 6, programs that require high-speed processing, such as online programs, make input/output requests using the device address in the device management table 4a, and programs that handle large amounts of data, such as volume backups, do not. An input/output request is made using the device address in the device management table 4b.

In this way, the input/output supervisor 2 receives an input/output request issued by specifying a device address, and issues the request to the magnetic disk device 6 having two device addresses by specifying each device address. The input/output requests are accepted, and the input/output requests 14 that require high-speed processing and the input/output requests 15, 16, 17 that require low-speed processing are registered as elements of the input/output request queues 3a and 3b, respectively, and the input/output requests are processed. Processing is scheduled.

When executing an input/output operation for an input/output request with respect to the magnetic disk device 6, the input/output supervisor 2 sets up two channel buses via the magnetic disk controllers 5a and 5b, and executes an input/output request for each. The input/output request 14 and the input/output request 15 are taken out from the queues 3a and 3b, and at the same time a request is made to the magnetic disk device 16 to process the input/output request. In this case, the magnetic disk device 6 It simultaneously accepts requests to execute input/output requests for the two device addresses listed and starts processing. For the accepted input/output operation execution request, first, the priority processing control unit 11 determines the priority order for executing the input/output operation processing. As a result, the input/output operation of the input/output request 14 issued from the device management table 4a side is started, and the processing of the input/output request 15 issued from the device management table 4b side is performed by the input/output request pending processing unit 12. It is held by '1'.

This is suspended until the input/output operation of the input/output request 14 issued from the device management table 4a side is completed, and when the input/output operation of the input/output request 14 currently being executed with a high processing priority is completed. will be restarted. Further, for example, when the input/output request 15 issued from the device management table 4b side is being operated on the magnetic disk device 6, the device management table 4a
When the magnetic disk device 6 receives an operation execution request for the input/output request 14 from the side, the priority processing control unit 11 determines which of the input/output requests 15 that is already being executed and the input/output request 14 that has just been accepted has priority for processing. is high. In this case, the input/output request 14 that has just been accepted is determined to have a high priority, so the input/output request 15 from the device management table 4b, which has a low priority, is put on hold in the input/output request holding processing unit 12, and The input/output request 14 on the device management table 4a side having a higher priority is executed first.

When the input/output operation of this input/output request 14 is completed, next, the input/output operation of the input/output request that was held in the input/output request suspension processing section 12 is restarted.

In this way, a magnetic disk device with two device addresses determines the processing priority of input/output requests from multiple channel buses, and processes input/output requests including pending processing of currently executing processing. Executes input/output operations.

2yII is a flowchart showing the processing flow of the input/output request execution processing performed by the magnetic disk device.

This will be explained with reference to FIG. When an input/output execution request is issued from the central processing unit to the magnetic disk unit through a channel or magnetic disk control unit.

First, in step 20, the priority processing control section checks whether the magnetic disk device in question is in operation. If it is not in operation, the process proceeds to step 25 and executes the received input/output request as is.

Also, if the magnetic disk device is running.

Proceeding to step 21, the priority processing control unit compares the priorities of the device address of the active input/output request and the device address of the accepted input/output request. If the operating device address has a higher processing priority, the process proceeds to step 22, where the operating state is reported to the magnetic disk control device that requested the execution of one input/output request, and the processing ends. As a result, the magnetic disk control device reports to the channel that it is in operation.

Further, in the determination process of step 21, if the device address that received the request to execute the input/output request has a higher priority than the device address currently being executed, in step 23, the Interrupt the process and proceed to step 24
In step 25, an interruption report is sent to the magnetic disk control device, and processing of the input/output request accepted in step 25 is executed.

That is, when the priority processing control unit determines that the device address that received the input/output request has a higher priority than the device address of the input/output request that is being executed.

Instructs the input/output request suspension processing unit to suspend the input/output operation being executed. As a result, when the input/output request pending processing unit finishes processing the record that is currently being processed, the input/output request suspension processing unit can move
(for example, cylinder number, track number, record number), and at the same time as interrupting the operation, reports the interruption of the input/output operation to the magnetic disk control device that was in execution. As a result, the magnetic disk controller interrupts the connection with the channel, waits for a restart instruction from the magnetic disk device, and informs the priority processing controller that the I/O request pending processor has completed the pending process. When the input/output request is received, the priority processing control unit executes processing of the received input/output request.

When the input/output operation with a high priority is completed in this way, the priority processing control unit reports completion to the magnetic disk controller in step 26, and then in step 27
In this step, the input/output request suspension processing section determines whether there is any pending input/output request processing. If there is a pending I/O request, the magnetic disk controller that reported the interruption is notified of restart in step 28, and after receiving notification from the magnetic disk controller that the channel has been reconnected, step 28 is executed. At step 29, execution of the input/output operation of the pending input/output request is restarted from the interruption point. Further, if there is no pending input/output request in step 27, the process ends.

In this way, according to this embodiment, even if there is an input/output request that is already being executed for the same device, if an input/output request with a higher processing priority than that input/output request occurs, the process is already executed. Holds the I/O operations in progress, executes the I/O requests that occur later with higher priority, and restarts the pending I/O requests when the I/O operations are completed. do. This makes it possible to prevent an input/output request with a high processing priority from being kept waiting because the input/output operations of other input/output requests are being executed.

The present invention has been specifically explained above based on examples, but
It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

〔Effect of the invention〕

As explained above, according to the pending input/output control method of the present invention, execution of input/output requests with high processing priority is
This eliminates the need to wait while another input/output request is already being executed by the same input/output device. Therefore, even if an input/output request to the same input/output device is executed simultaneously by a program that requires a high response, such as an online program, and a program that handles large amounts of data, such as a volume backup. .

This has the effect of not slowing down the execution time of input/output requests issued by programs that require high response times in online programs.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of essential parts of a data processing system that schedules and executes processing of input/output requests according to an embodiment of the present invention. FIG. 2 is a flowchart showing the processing flow of the input/output request execution processing performed by the magnetic disk device, and FIG. 3 is a block diagram illustrating the processing of the input/output supervisor that executes the processing of the input/output request. In the figure, 1.31...Central processing unit, 2.32...I/O supervisor, 3a, 3b, 33...I/O request queue, 4a, 4b, 34-device management table, 5a
. 5 b, 35... magnetic disk control device, 6,3
6...Magnetic disk device, 11...Priority processing control section, 12...I/O request pending processing section, 13...Magnetic disk device section, 14°15, 1G, 17.40.41
．． 42. ...I/O request. Notebook 1□□□

Claims (1)

[Claims] 1. For the same input/output device, provide multiple device addresses with different processing priorities, specify the device address and make an input/output request, and check if the input/output device has already received input. When an output request is being executed and an input/output request occurs at a device address with a higher priority for the input/output device, the input/output operation that is already being executed is held and the priority level that occurs later is A pending input/output control method characterized in that an input/output request at a device address with a higher address is executed first, and the suspended input/output request is restarted when the processing operation of the input/output request is completed. 2. Prepare two device addresses, a high-speed access device address and a low-speed access device address, for the same input/output device, and process input/output requests issued to the high-speed access device address. , if an input/output operation is already in progress at the low-speed access device address of the same input/output device, the input/output operation being executed at the low-speed access device address is temporarily suspended on the input/output device side, and The present invention is characterized in that an input/output request issued to an access device address is executed first, and when that input/output operation is completed, the input/output operation of the pending low-speed access device address is restarted. A pending input/output control method. 3. Manage the input/output device by assigning two device addresses for the same input/output device: a device address for high-speed, small-volume processing and a device address for low-speed, high-volume processing. An input/output request schedule processing unit that schedules output requests, and a priority module that determines whether an input/output operation execution request is made to a high-speed, high-volume processing device address while an input/output operation is being executed at a low-speed, high-volume processing device address. According to instructions from the processing control unit and the priority processing control unit, the input/output device in question temporarily suspends the input/output operations being executed at the low-speed, large-volume processing device address, and performs input/output operations issued to the high-speed, small-volume processing device address. A suspension type characterized by having an input/output request suspension processing unit that executes the operation execution request first and restarts the input/output operation of the temporarily suspended low-speed, small-volume processing device address after the input/output operation is completed. I/O controller. 4. The pending type input/output according to claim 3, wherein the input/output schedule processing section is provided in the input/output supervisor, and the priority processing control section and the input/output request pending processing section are provided in the input/output device. Control device.