JPS62274357A - Input/output scheduling system - Google Patents

Abstract

PURPOSE:To accurately deal with error occurrence during the processing of an input/output request by reporting the occurrence of an error and disregarding successive input/output requests if the error occurs to the input/output request being processed. CONSTITUTION:It is decided in an input/output end interruption processing task 7A whether an error occurs or not, and when the occurrence of the error is judged, a change is so made as to set the contents SHUT of an error occurrence report flag 9 to 1 and the error occurrence is reported to the side of an input/output request processing routine 6A. Then, the contents of a flag 10 of the 1st time are checked to remove and discard a succeeding input/output request if it is registered in an input/output request queue. When it is judged that there is not error, on the other hand, a corresponding task is posted and when a necessary input/output request is registered in the queue 8, a corresponding input/output start is made. Consequently, while the advantage of the saving of an overhead time is maintained, the error occurrence in the processing of an input/output request is accurately dealt with.

Description

[Detailed Description of the Invention] 3 Detailed Description of the Invention [Field of Industrial Application] This invention relates to an input/output scheduling method, and
, a flexible input/output scheduling scheme for input/output devices in a total $4 system.

[Conventional technology]

FIG. 3 is a schematic diagram of a conventional input/output scheduling method, and FIG. 9 is a schematic diagram showing the main part of the conventional example. In these figures, appropriate input/output devices are connected to the data processing device f (c), and a memory section (not shown) of the data processing device (c) is connected to the data processing device f (c). User program created according to the needs of (3)
, and a control program (g) for dealing with various requests from this user program (31).Furthermore, a control program (g) for handling various requests from the user program (31) is stored. is this user program (
,? ) is used to issue the required input/output requests under the control program (ri), and includes the input/output request processing routine (6) and the input/output completion interrupt processing task (
71, the former is a user program (, yl
The latter is called by the input/output request source task (S) in order to process the input/output request from the input/output device (x+ It is for processing.

Note that (g) shows an input/output request queue, and is an input/output device! This occurs regarding an input/output request issued when 11 [g) is in use.

FIG. 5 is a flowchart for explaining the operation in the conventional train. The operation of the conventional train will now be described with reference to FIG. 5.

Now, the step (Sff/) of the input/output request task (S)
Assume that an input/output request l, which is the first input/output request, is issued by an appropriate READ command or WRITE command. In response to the issuance of such an input/output request "/, the input/output request processing routine (6) is started,
In that step (S67), the target input/output device @ (
It is determined whether 21 is vacant or not.

When this is determined to be Y, the target input/output device (
Since it is shown that ``)'' is vacant, an input/output activation is immediately issued in step (S6). On the other hand, when N is determined, it indicates that the target input/output device (2) is not available, so
・In step (St, 3), the input/output request/ is registered in the input/output request queue (71) and then the input/output request task (
Returning to the jl side, the next I/O request will be processed. Also, the I/O completion interrupt corresponding to the I/O activation for a certain I/O request will be sent to the data processing device (in C). When generated from a data channel (not shown), the I/O completion interrupt handling task (71 makes the I/O request task (sr ready, i.e., posts 6) and registers it in the I/O request queue (1). If there are still input/output requests remaining, the corresponding input/output activations are subsequently scheduled and issued.

[Problem that the invention seeks to solve]

Since the conventional scheduled input/output method is configured and operated as described above, the processing process for any one of the multiple input/output requests issued to a certain specified input/output device is There is a problem in that when some kind of error occurs, the input/output request subsequent to the first one is scheduled, and the input/output request task is not executed correctly. Also, to avoid such inconvenience.

It is possible to limit the number of I/O requests to 7 to avoid creating a queue of I/O requests, but this would increase overhead time and reduce overall processing efficiency. This invention was made to solve the above problems, and the I/O completion interrupt schedules the I/O requests registered in the queue based on the task. In addition, if any error occurs in the process of processing any of the multiple input/output requests, the first subsequent input/output request is canceled,
and.

It is now possible to notify the occurrence of the error in response to an input/output request. Aiming to obtain a highly flexible schedule input/output method 6 [Means for solving the problem] The input/output schedule method according to the present invention has a data processing device and an attached input/output device. This is an input/output scheduling method that schedules input/output requests to and from a device, and includes an input/output request source task that issues the required input/output requests, and an input/output request processing routine that performs the required processing for the input/output requests. , an input/output completion interrupt processing task that is interrupted by the input/output device when the input/output operation related to the input/output request is completed, and the first schedule and other schedules related to the input/output request processing routine. To identify the /th flag.

This task is related to the input/output completion interrupt processing task and includes an error occurrence notification flag that notifies the occurrence of an error regarding the input/output request being processed.

[For production]

According to the present invention, when an error occurs regarding an input/output request currently being processed, the content of the error occurrence notification flag is changed to notify the input/output request processing routine that the error has occurred.

By examining the contents of the above/th routine.

When it is identified that the next I/O request is registered in the I/O request queue, the next I/O request is discarded.

〔Example〕

FIG. 1 is a schematic diagram showing a main part of an embodiment according to the present invention. In FIG. 1, (ri) is an error occurrence notification flag, and the previous This is to prevent issuing an erroneous input/output activation when there is an error in the input/output request of the input/output request processing routine (10), which is the seventh flag. 4.') This is to identify the 1st schedule from the 2nd and subsequent schedules. In addition.

In FIG. 1, the same reference numerals as those in FIG. 3 or FIG. 3 described above indicate the same or corresponding parts.

FIG. 2 is a flowchart for explaining the operation in the above embodiment. The operation of the above embodiment will be explained below with reference to FIG. 2.

In the input/output requesting task (5A), an appropriate READ
In this input/output request processing routine (6A), a required input/output request is issued by a command or a WRITE command and is transmitted to the input/output request processing routine (6A). Prior to determining whether or not (=) is empty, it is determined in step (SbO) whether or not the content 5HUT of the error occurrence notification flag (9) is "o". When it is determined that this is Y, it is determined whether the target input/output device (2) is free or not, as in the case of the conventional example, and it depends on whether it is Y or N. immediately issue the corresponding I/O invocation, or.

It will now be registered in the input/output request queue.

However, when it is determined that it is N.

Assuming that the previous input/output request (assuming that the current input/output request is an input/output request, the previous one corresponds to an input/output request/) ended in error, will perform appropriate error handling within the input/output request source task (5A), but in the input/output request processing routine (6A), the process moves to step (864') and the /th flag (10) is set. A determination is made whether the content 0NCE is "O". Now, when it comes to N, that is.

0NCE\O, and the current schedule is identified as the λth or later schedule, the process waits for the completion of processing for the previous input/output request.

Error occurrence notification flag (Check the contents of 91 and depending on the contents, directly return the exit status,
Or, initialize the content of the /th flag (/θ); (reset and then return the completion status.On the other hand, when it is Y, that is, 0NCE=0, and the current When the schedule is identified as the seventh one, it is clear that processing for the previous input/output request is not necessary, and the contents of the seventh flag (10) are changed.

This is returned after setting the exit status to normal.

Next, in the input/output completion interrupt processing task (7A), it is determined in step (87/) whether or not there is an error, and when it is determined to be Y, that is, it is determined that there is an error. Sometimes, the error occurrence notification flag (9
Change the contents of 1 so that 5HUT becomes @/'',
The input/output request processing routine (6A) side is notified of the error occurrence, and if the next input/output request is registered in the input/output request queue, it is removed and discarded. On the other hand, when it is determined that the error is N, that is, when it is determined that there is no error, the above-mentioned processing is not performed, and as in the case of the conventional example, the corresponding task is bossed and the required input/output request is executed. is the I/O request queue (
When it is already registered in ff+.

You will set a schedule for this and issue the corresponding I/O activation.

In the above embodiments, processing for input/output requests is described as being carried out by the input/output request processing routine, but the routine is not limited to this; for example, it may be called by a supervisor call (SVC) command. The necessary processing may be performed by an input/output coupler within the operating system ('O8).

〔Effect of the invention〕

As explained above, the input/output scheduling method according to the present invention is a method for determining the schedule of input/output requests between a data processing device and an input/output device attached thereto. An input/output request source task that issues an input/output request, an input/output request processing routine that performs the necessary processing for the input/output request, and an input/output request processing routine that receives an interrupt from the input/output device when the input/output operation related to the input/output request is completed. The input/output completion interrupt processing task related to the input/output request processing routine described above, the first flag for distinguishing the /th schedule from other schedules, and the processing associated with the input/output completion interrupt processing task described above. It includes an error occurrence notification flag that notifies the occurrence of an error related to an input/output request.

When an error occurs regarding an input/output request currently being processed,
By changing the contents of the error occurrence notification flag and notifying the input/output request processing routine that the above error has occurred, and checking the contents of the above/th routine, the first subsequent input/output request is changed to an input/output request. The advantage of saving overhead time by queuing an I/O request is that when it is identified that the I/O request is queued, the next I/O request is discarded. It is possible to accurately deal with errors that occur during input/output request processing while maintaining the same level of performance.

The effect is that the overall processing speed, including input/output scheduling, is significantly improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the main parts of an embodiment of the present invention, FIG. 2 is a flowchart diagram for explaining the operation of the above embodiment, and FIG. 3 is a schematic diagram of a conventional example. The figure is a schematic diagram showing the main parts of the above-mentioned conventional example. FIG. S is a 70-chart diagram for explaining the operation of the conventional example. (C is a data processing device, C2 is an input/output device, (3) is a user program, [gl is a control program, III
, (!k) is the input/output request source task, (b'), (bA)
is the input/output request processing routine, (?), r7A) is the input/output completion interrupt processing task, (t) is the input/output request queue, (9) is the error occurrence notification flag, and (10) is the 7th flag. In each figure, the same reference numerals indicate the same or similar parts. IQ: / Mouth Eye Furano 8: Crowd 77 School 'f+t) Row j'J Crow 4 Figure 8: Input/Output Oi 454 Dimensions Dali City 5 Figure Procedure Amendment ``Spontaneous'' no! 113. ,S,-ya. .

Claims (1)

[Claims] An input/output scheduling method that determines a schedule for input/output requests between a data processing device and an input/output device attached to the device, in which an input/output request source task that issues the required input/output request, and an input/output request source task for issuing the required input/output request, and An input/output request processing routine that performs necessary processing for the request, an input/output completion interrupt processing task that is interrupted by the input/output device when the input/output operation related to the input/output request is completed, and the input/output request processing routine. Related to this, there is a first flag that identifies the first schedule and other schedules, and an error occurrence notification flag that is related to the input/output completion interrupt processing task and notifies the occurrence of an error regarding the input/output request being processed. When an error occurs regarding the input/output request currently being processed, the content of the error occurrence notification flag is changed to notify the input/output request processing routine that the error has occurred, and the first routine An input/output scheduling method that discards the next succeeding input/output request when it is identified that the next succeeding input/output request is registered in an input/output request queue by checking the contents of the input/output request queue.