JP4407654B2 - I / O request control method, computer system, and computer program - Google Patents

Description

  The present invention relates to a method for controlling the processing order of input / output requests in a computer system, a computer system, and a computer program.

  In the computer system, in order to process the input / output requests of the processing program, the priority of the input / output requests and the priority of the processing device such as the target input / output device are not processed in the order in which the input / output requests are generated. Generally, the processing order of input / output requests is determined based on the above.

  For example, Patent Document 1 describes a technique in which a processing program sets an arbitrary priority for an input / output request and controls so that a request with a low priority does not wait for a long time. In the technique of Patent Document 1, each input / output request registered in the queue has information on the number of times it has been overtaken by a request having a higher priority than itself and the number of times allowed to pass. When an input / output request is received from the processing program, entries are registered in the priority control table so that they are arranged in the set priority order. When registering an I / O request in the priority control table, if an I / O request is overtaken by the registered I / O request, the number of overtakes is counted up. Move to the head of the queue. When executing input / output processing, the input / output request at the head of the queue is taken out and input / output processing is performed.

  U.S. Patent No. 6,057,836 provides an enhanced method and apparatus for scheduling resources for multiple jobs. The job scheduler makes decisions regarding the order and frequency of access to resources according to a substantially optimal delay cost function. The delay cost function is a single-value or multi-input single value function, at least one of the inputs being a delay time that increases as the job waits for service. The delay cost function can be of any shape and can be dynamically adjusted to produce an optimal delay cost for a given set of user-defined performance goals, system configurations or workloads.

Japanese Patent Application Laid-Open No. 2004-151867 can specify the desired print completion deadline, and if the printing is not in time by the designated deadline, the print request job can be preferentially executed and the print request job Describes a technology that realizes efficient print control as a whole so as not to cause inconvenience that printing of other subsequent print waiting request jobs will not be in time for the print completion deadline Has been. In the technique of Patent Literature 3, when a print completion deadline indicating when the printing is desired to be completed is arbitrarily designated at the time of a print request, the server computer allows each print request job waiting for printing to be printed. The printing order of each job is changed in the arrangement order so that the printing is in time for the deadline. When the print order is changed, the server computer determines whether there is a print request job that is not in time for the print completion deadline. If there is, the server computer designates another alternative printer device and outputs the job. Change the destination.
JP-A 1-1112461 JP 7-175669 A JP 2001-236195 A

  In the conventional technology, the processing order of I / O requests is managed by priority and overtaking number. When a large number of I / O requests with high priority are issued temporarily, the priority already queued. However, there is a problem that I / O requests with low priority are processed one after another, and I / O requests with high priority are greatly delayed.

  Further, since the time at which the input / output request should be started is not taken into account, there is a problem that an input / output request with a low priority that does not need to start processing moves to the head of the queue.

  The technique of Patent Literature 3 is a case where an alternative printer device that processes a print request job that is not in time for the print completion deadline is provided, and a case where there is no alternative processing device is not assumed.

  The present invention has been made in view of the above circumstances, and the input / output request requested by a specific processing program is not significantly delayed, and the delay between the processing programs requesting input / output is equalized. It is an object of the present invention to provide a processing order control method for output requests.

An input / output request control method according to a first aspect of the present invention includes:
An input / output control method having a priority control function in a computer system for centrally controlling input / output requests to a processing device from a plurality of processing programs,
The processing program includes a processing time required for processing in the processing device, an end time that is a time at which the processing is to be ended, and a priority designation that is specified when input / output is given priority over other input / output. An input / output requesting step for making an input / output request to the processing device;
The input / output request is calculated from the reception time received from the processing program when the priority is specified , and the input / output request is specified as the input / output request when the priority is not specified. has been the processing time and end time or al, the start time setting step of setting calculates the start time of the input output request,
A registration step of registering the input / output request in a queue in the order of the start time calculated in the start time setting step;
Retrieving the I / O requests registered in the queue in order of the start time;
When the input / output request is extracted from the queue in the extraction step, if the time when the input / output request is extracted does not exceed the start time set in the input / output request, the input / output request is A process start step to be passed to the processing device;
When the I / O request is taken out from the queue in the fetching step, if the current time at which the I / O request is taken has passed the start time set in the I / O request, it is registered in the queue With respect to the input / output request, the delay is calculated from the reception time and start time of the input / output request and the current time, and the input / output request with the maximum delay is taken out from the queue and sent to the processing device. A selection process start step to pass,
It is characterized by providing.

  In particular, the degree of delay is based on a value obtained by dividing a difference between the current time and the start time by a difference between the current time and the reception time.

A computer system according to a second aspect of the present invention is:
A computer system for centrally controlling input / output requests to a processing device from a plurality of processing programs,
The processing program includes a processing time required for processing in the processing device, an end time that is a time at which the processing is to be ended, and a priority designation that is specified when input / output is given priority over other input / output. An input / output requesting means for making an input / output request to the processing device;
The input / output request is calculated from the reception time received from the processing program when the priority is specified , and the input / output request is specified as the input / output request when the priority is not specified. has been the processing time and end time or al, the start time setting means calculates and sets the start time of the input output request,
Registration means for registering the input / output requests in a queue in the order of the start times calculated by the start time setting means;
Processing control means for taking out the input / output request registered in the queue and passing it to the processing device;
With
The processing control means includes
Taking the I / O requests out of the queue in order of the start times;
When the input / output request is taken out from the queue, if the current time when the input / output request is taken out does not exceed the start time set in the input / output request, the input / output request is sent to the processing device. Hand over,
When the current time has passed the start time set in the input / output request, for the input / output request registered in the queue, the reception time of the input / output request, the start time, and the current time A delay is calculated from the I / O request with the maximum delay is taken out of the queue and passed to the processing unit;
It is characterized by that.

  Preferably, the degree of delay is based on a value obtained by dividing a difference between the current time and the start time by a difference between the current time and the reception time.

A computer program according to a third aspect of the present invention provides a computer,
Specify the processing time required for processing in the processing device, the end time that is the time at which the processing should be terminated, and the priority designation that is specified when input / output is given priority over other input / output. Input / output request means for making an input / output request to the processing device;
The input / output request is calculated from the reception time received from the processing program when the priority is specified , and the input / output request is specified as the input / output request when the priority is not specified. has been the processing time and end time or al, the start time setting means calculates and sets the start time of the input output request,
Registration means for registering the input / output request in a queue in the order of the start times set by the start time setting means;
Retrieving means for retrieving the input / output requests registered in the queue in order of the start time;
When the I / O request is taken out from the queue by the take-out means, if the time when the I / O request is taken out does not pass the start time set in the I / O request, the I / O request is Processing start means to be passed to the processing device;
When the fetching means fetches the I / O request from the queue, if the current time when the I / O request was fetched has passed the start time set in the I / O request, it is registered in the queue With respect to the input / output request, the delay is calculated from the reception time and start time of the input / output request and the current time, and the input / output request with the maximum delay is taken out from the queue and sent to the processing device. Selection processing start means to be passed,
It is characterized by functioning.

  According to the input / output request processing order control method of the present invention, when an input / output request of a processing program is registered (enqueued) in a queue, the end time specified by the processing program and the start time determined from the processing time are in order. Since enqueues are arranged in line, input / output is performed so as to satisfy the end time specified by the processing program. Further, even when the input / output request load is high, the specific input / output is not significantly delayed, and the delay is equalized.

  Hereinafter, a processing order control method and a computer system for input / output requests according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a computer system according to an input / output request control method according to an embodiment of the present invention. FIG. 2 is a block diagram showing an example of a physical configuration of the computer system of FIG. FIG. 3 is a diagram showing a configuration example of the input / output request management table according to the embodiment of the present invention. FIG. 4 is a diagram showing a configuration example of the input / output request entry according to the embodiment of the present invention. FIG. 5 is a diagram for explaining a delay degree calculation method according to the embodiment of the present invention.

  As shown in FIG. 1, a computer system 1 according to the present embodiment includes a processing program group 2 including a plurality of processing programs 21, 22, and 23, an input / output request reception unit 3, an input / output request registration unit 4, and the like. The input / output request management table 5, the input / output request selection unit 6, the delay degree calculation unit 7, the input / output request processing unit 8, the processing completion notification unit 9, and the processing device 10.

  The processing device 10 is generally a device that executes processing requested by a processing program. In this embodiment, for example, an input / output device such as a disk device or a tape device is assumed. Other examples of the processing device include an image data input device, a printer device, an image processing device that analyzes or encodes image data, a data encryption / decryption device, a signal processing device such as FFT, and the like. included.

  The input / output control method of the present invention is a method of controlling the input / output processing order for one processing device (or one type of processing device group). When there are a plurality of processing devices of different types (or a group of processing devices), the processing order of input / output requests is controlled for each type of processing device.

  The input / output request receiving unit 3 receives input / output requests from the processing programs 21 to 23. When receiving an input / output request, if input / output to the processing device 10 is possible, the input / output request processing unit 8 is activated. When an input / output request is received, if the input / output to the processing device 10 is not possible, the input / output calculated from the reception time, the end time of the input / output request, and the time required for the processing process should be started. The time (hereinafter referred to as start time) is set in the input / output request, and the input / output request registration unit 4 is activated.

  The input / output request registration unit 4 registers the input / output requests in the input / output request management table 5 so that they are arranged in the order of the start times set in the input / output requests. As shown in FIG. 3, the input / output request management table 5 includes an input / output request queue (input / output request queue) 51 and a target end time 52. The input / output requests registered in the input / output request management table 5 are arranged in the input / output request queue 51 in the order of start time as input / output request entries (hereinafter abbreviated as entries). In practice, the first entry 512 is indicated by the pointer of the header 511, the second entry 513 is indicated by the pointer of the first entry 512, and the input / output request entries are successively pointers of the previous input / output request entries. You may comprise as shown by.

  The target end time 52 is a standard time from when an input / output request is received until the processing by the processing device 10 is completed in the processing device 10 that is the target of the input / output request management table 5. For example, it is a time obtained by adding a margin to a substantial average processing time in the processing apparatus 10. If the processing time changes depending on the data amount, such as proportional to the data amount of the input / output request, a function such as the data amount may be used.

As shown in FIG. 4, the input / output request entries 512 to 514 are composed of a reception time, a start time, and input / output contents. The reception time is the time when the input / output request reception unit 3 receives the input / output request. The start time is the time at which I / O must start in order to complete the process by the end time,
Start time = end time-processing time. The start time is calculated from the end time and the processing time by the input / output request accepting unit 3. The input / output content is information indicating input / output such as writing and reading commands to the processing device 10 and processing content of the processing device 10.

  The input / output request selection unit 6 extracts the first input / output request entry 512 (indicated by the header 511 in FIG. 3) from the input / output request queue 51 of the input / output request management table 5. However, if the current time at which an entry is extracted has passed the start time of the entry, the entry having the maximum delay is extracted from the input / output request queue 51 among the registered entries.

The delay degree calculation unit 7 calculates the delay degree of the input / output request entries 512 to 514. (A) of FIG. 5 shows the calculation formula of the delay degree of this Embodiment. FIG. 5B schematically shows an example of the relationship between the reception time, the start time, and the end time on the time axis, and the denominator and the numerator time of the delay degree expression of FIG. The degree of delay is obtained by the calculation formula of FIG. In this embodiment, the degree of delay is
Degree of delay = (current time-start time) / (current time-reception time)
It is a value calculated by. That is, it is the ratio of the time from when the input / output request is received to when the entry is read out, when the current time exceeds the start time (see FIG. 5B). If the start time is smaller (before) the reception time due to the designation of the end time and the processing time, the delay degree is set to 1. If there is priority designation, the start time is the reception time. In that case, the degree of delay is 1. In the present embodiment, the degree of delay is represented by a number of 1 or less, and the maximum value is 1.

  Therefore, even if the reception time is early, if the start time is late, the degree of delay becomes small and priority processing is not performed. Even if the reception time is late, if the start time is close to the reception time, or is the same as or earlier than the reception time, the delay degree is close to 1, so that the processing is preferentially performed. The degree of delay is calculated based on the start time obtained from the end time and the processing time. Even if there are many I / O requests for the processing device and the actual start of processing has passed the set start time, I / O requests are processed with a large delay, so I / O requests with a specific priority There is no significant delay in processing, and delays are equalized according to priority.

In addition to the equation of FIG.
Degree of delay = (current time-reception time) / (start time-reception time)
Or
Degree of delay = (current time-start time) / (start time-reception time)
It may be. However, in these cases, the start time is set to be later than the reception time.

  The input / output request processing unit 8 executes input / output with respect to the processing device 10 when activated by the input / output request receiving unit 3. When activated from the processing completion notification unit 9, the input / output request selection unit 6 extracts an entry from the input / output request queue 51 and executes input / output to the processing device 10.

  When the processing completion notification unit 9 receives the processing completion notification from the processing device 10, the processing completion notification unit 9 notifies the processing program that issued the input / output request of the completion of input / output. Also, the input / output request processing unit 8 is activated to execute the input / output request entry registered in the input / output request queue 51 of the input / output request management table 5.

  As shown in FIG. 2, the computer system 1 according to the input / output request processing order control method of the present invention shown in FIG. 1 includes a control unit 11, a main storage unit 12, an external storage unit 13, a timer unit 14, and an operation unit 15. , Display unit 16, input / output unit 17, and processing device 10. The main storage unit 12, the external storage unit 13, the timing unit 14, the operation unit 15, the display unit 16, and the input / output unit 17 are all connected to the control unit 11 via the internal bus 19.

  The control unit 11 includes a CPU (Central Processing Unit) and the like, and according to a program stored in the external storage unit 13, an input / output request reception unit 3, an input / output request registration unit 4, and an input / output request selection unit 6 The processing of the delay degree calculation unit 7, the input / output request processing unit 8, and the processing completion notification unit 9 is executed. Further, the processing of the processing program group 2 is also executed by the control unit 11. The input / output request reception unit 3, the input / output request registration unit 4, the input / output request selection unit 6, the delay calculation unit 7, the input / output request processing unit 8, and the processing completion notification unit 9 are executed on the control unit 11 and above. It is realized by a program.

  The main storage unit 12 includes a RAM (Random-Access Memory) and the like, and is used as a work area for the control unit 11. The input / output request management table 5 is stored and held in a part of the main storage unit 12 as a storage area structure.

  The external storage unit 13 includes a nonvolatile memory such as a flash memory, a hard disk, a DVD (Digital Versatile Disc), a DVD-RAM (Digital Versatile Disc Random-Access Memory), a DVD-RW (Digital Versatile Disc ReWritable), and the like. A program for causing the control unit 11 to perform the above process is stored in advance, and data of the program is supplied to the control unit 11 according to an instruction from the control unit 11, and the data supplied from the control unit 11 is stored.

  The timer unit 14 counts clock pulses, for example, and measures time based on a count value from a reference time. The control unit 11 can know the time at that time by referring to the count value of the time measuring unit 14. For example, the reception time when the input / output request is received and the current time when the input / output request entry is taken out are measured by the count value of the timer unit 14.

  The operation unit 15 includes a pointing device such as a keyboard and a mouse, and an interface device that connects the keyboard and the pointing device to the internal bus 19. Commands such as start / stop of the computer system 1, start / stop of the processing program, status display of the processing program, status display of the input / output request management table 5 are input via the operation unit 15 and supplied to the control unit 11. The

  The display unit 16 is configured by a CRT (Cathode Ray Tube) or an LCD (Liquid Crystal Display), and the status and input / output of the processing program group 2 according to commands from the control unit 11 according to commands input from the operation unit 15. The status of the management table 5 is displayed.

  The input / output unit 17 includes a serial interface, a parallel interface, or a LAN (Local Area Network) interface. A processing request is input to the processing device 10 via the input / output unit 17 or an output of processing results is received from the processing device 10.

  As described above, the processing device 10 is an input / output device such as a disk device or a tape device, an image data input device, a printer device, an image processing device, a data encryption / decryption device, or a signal processing device. Executes processing according to the processing program request and outputs the result.

  Next, the operation of the computer system 1 shown in FIGS. 1 to 5 will be described with reference to FIGS. As described above, the operation of the computer system 1 is performed by the control unit 11 in cooperation with the main storage unit 12, the external storage unit 13, the timing unit 14, the operation unit 15, the display unit 16, the input / output unit 17, and the processing device 10. To work.

  FIG. 6 is a flowchart showing the operation of processing for accepting an input / output request. When the input / output request accepting unit 3 receives an input / output request from any of the processing programs 21 to 23, it checks whether input / output to the processing apparatus 10 is possible (step A1). (A1; Yes), the input / output request processing unit 8 is activated and input to the processing device 10 (step A2). If not possible (step A1; No), the current time is acquired as the reception time (step A3).

  Next, the priority designation of the input / output request is checked (step A4). For example, if there is a priority designation as in the case of the input / output request of the processing program 22 (step A4; Yes), the reception time is set as the start time ( Step A10). As in the case of the input / output request of the processing program 21 or the processing program 23, if there is no priority designation (step A4; No), the end designation time is checked (step A5), and if there is no end time designation (step A5; No) Then, a value obtained by adding the target end time 52 to the reception time is set as the end time (step A6). If the end time is specified (step A5; Yes), the end time is not set.

  Also, the processing time designation is checked (step A7), and if there is no processing time designation (step A7; No), the predicted processing time calculated from the type of the processing device 10, the input / output data size, etc. is set as the processing time ( Step A8). If the processing time is specified (step A7; Yes), the processing time is not set. Then, a value obtained by subtracting the processing time from the end time is set as the start time (step A9).

  The input / output request registration unit 4 registers the input / output requests in the input / output request queue 51 of the input / output management table 5 so that the arrangement of the input / output request entries 512 to 514 is in the order of the start time.

  The input / output request processing unit 8 executes input / output with respect to the processing device 10 when activated by the input / output request receiving unit 3. When activated from the processing completion notification unit 9, the input / output request selection unit 6 extracts an input / output request from the input / output request queue 51 and executes input / output to the processing device 10. Upon receipt of the input / output completion notification from the processing device 10, the processing completion notifying unit 9 notifies the program that issued the input / output request of the completion of the input / output, and the input / output request queued in the input / output request queue 51. In order to execute, the input / output request processing unit 8 is activated.

  FIG. 7 is a flowchart showing an operation of processing for selecting an input / output request from the input / output request management table 5. The input / output request selection unit 6 first sets 1 as an internal variable, 1 as n, and 0 as d (step B1), and acquires the current time (step B2). m is a variable representing the number of the input / output request in order to calculate the delay degree of each input / output request. n is a variable representing the number of the input / output request with the maximum delay. d is a variable for comparing the maximum value of the delay degree, and finally becomes the maximum value of the delay degree.

  Next, it is checked whether the start time of the first input / output request is delayed (step B3). If not delayed (step B3; No), the first input / output request in the input / output request queue 51 is extracted. (Step B8), input / output is executed. If it is delayed (step B3; Yes), the delay calculation unit 7 is activated to calculate the delay d (1) of the leading input / output request (step B4).

  It is checked whether the value of d (1) is larger than d (initial value = 0) (step B5). If Yes, d (m) is set in d and m is set in n (step B6). On the other hand, if No, step B6 is skipped. For example, in the case of m = 1, which is the first processing loop for calculating the delay of input / output requests, d (1) is greater than 0, so Yes, d is set to d (1), and n is set to 1. (Step B6). Then, m + 1 (= 2) is set to m (step B7). Also for the second and subsequent input / output requests, it is checked whether the start time of the input / output request is delayed until an undelayed input / output request is found (step B3).

  Since the input / output request entries 512 to 514 are arranged in the order of the start time in the input / output request queue 51, when an input / output request whose start time is later than the current time is found, the subsequent input / output requests indicate the start time. Not too much. Since the delay degree of the input / output request that has not passed the start time is negative as shown in the equation of FIG. 5, it is not necessary to calculate the delay degree of the subsequent input / output request.

  When an undelayed input / output request is found (step B3; No), the delay is maximized in the nth input / output request, so the nth input / output request is extracted (step B8). Execute the I / O request.

  If priority is specified as in the input / output request of the program 22, the input / output request reception unit 3 sets the reception time as the start time. Enqueued ahead of the queue. In addition, since the delay degree of the input / output request with priority designation is always 1, when the delay occurs, the input / output request selection unit 6 performs selection processing with priority.

  Further, as in the case of the input request of the program 21 and the program 23, if there is no priority designation, the end time (the value obtained by adding the target end time to the reception time when the end time is not designated) and the processing time (the processing time is not designated). In this case, the start time is determined by the predicted processing time). Then, the degree of delay is determined from the difference between the current time and the start time. Therefore, the earlier the end time, the longer the processing time, the earlier the start time. When enqueuing by the input / output request registration unit 4 is enqueued ahead of the input / output request queue 51. Also, the earlier the start time, the greater the delay degree. Therefore, when the delay occurs (when there is an input / output request whose current time has passed the start time), the input / output request selection unit 6 preferentially selects it. Processed.

  As described above, if there is no input / output request whose current time exceeds the start time, the first input / output request entry 512 of the input / output request queue 51 arranged in the order of the start time is selected and executed. If there is an I / O request whose current time has passed the start time, the delay expressed as the percentage of the time that the current time exceeds the start time in the time from receipt of the I / O request to reading of the entry The most frequent I / O request is selected and executed. Furthermore, since an input / output request with priority designation has a reception time as a start time and has a maximum delay of 1, it is processed prior to an input / output request without priority designation.

  As a result, input / output is performed so as to satisfy the end time specified by the processing programs 21 to 23. Even when the input / output request load is high, the specific input / output is not significantly delayed, and the delay is equalized.

  In addition, the hardware configuration and the flowchart described above are merely examples, and can be arbitrarily changed and modified.

  The computer system 1 can be realized using a normal computer system, not a dedicated system. For example, a computer program for executing the above operation is stored and distributed on a computer-readable recording medium (flexible disk, CD-ROM, DVD-ROM, etc.), and the computer program is installed in the computer. Thus, an apparatus that performs the above-described processing may be configured. Further, the computer system 1 of the present invention may be configured by storing the computer program in a storage device included in a server device on a communication network such as the Internet and downloading it by a normal computer system.

  When each of the above functions is realized by sharing an OS (operating system) and an application program, or by cooperation between the OS and the application program, only the application program part is stored in a recording medium or a storage device. Also good.

  It is also possible to superimpose the above computer program on a carrier wave and distribute it via a communication network.

It is a block diagram which shows an example of a structure of the computer system according to the input / output request control method which concerns on embodiment of this invention. It is a block diagram which shows an example of the physical structure of the computer system which concerns on embodiment of this invention. It is a figure which shows the structural example of the input / output request management table which concerns on embodiment of this invention. It is a figure which shows the structural example of the input / output request entry which concerns on embodiment of this invention. It is a figure explaining the calculation method of the delay degree which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement of the process which receives the input / output request which concerns on embodiment of this invention. It is a flowchart which shows the operation | movement of the process which selects an input / output request from the input / output request management table which concerns on embodiment of this invention.

Explanation of symbols

1 Computer system
2 Processing program group (input / output request means)
3 Input / output request acceptance unit (start time setting means)
4 Input / output request registration section (registration means)
5 I / O request management table (queue)
6 Input / output request selector (processing control means)
7 Delay calculator
8 Input / output request processing unit (processing control means)
9 Process completion notification section
10 Processing device
11 Control unit
12 Main memory
13 External storage
14 Timekeeping Department
15 Operation unit
16 Display section
17 Input / output section
19 Internal bus 21, 22, 23 Processing program
51 I / O request queue (queue)

Claims (5)

An input / output control method having a priority control function in a computer system for centrally controlling input / output requests to a processing device from a plurality of processing programs,
The processing program includes a processing time required for processing in the processing device, an end time that is a time at which the processing is to be ended, and a priority designation that is specified when input / output is given priority over other input / output. An input / output requesting step for making an input / output request to the processing device;
The input / output request is calculated from the reception time received from the processing program when the priority is specified , and the input / output request is specified as the input / output request when the priority is not specified. has been the processing time and end time or al, the start time setting step of setting calculates the start time of the input output request,
A registration step of registering the input / output request in a queue in the order of the start time calculated in the start time setting step;
Retrieving the I / O requests registered in the queue in order of the start time;
When the input / output request is extracted from the queue in the extraction step, if the time when the input / output request is extracted does not exceed the start time set in the input / output request, the input / output request is A process start step to be passed to the processing device;
When the I / O request is taken out from the queue in the fetching step, if the current time at which the I / O request is taken has passed the start time set in the I / O request, it is registered in the queue With respect to the input / output request, the delay is calculated from the reception time and start time of the input / output request and the current time, and the input / output request with the maximum delay is taken out from the queue and sent to the processing device. A selection process start step to pass,
An input / output request control method comprising:   The input / output request control method according to claim 1, wherein the delay degree is based on a value obtained by dividing a difference between the current time and the start time by a difference between the current time and the reception time. A computer system for centrally controlling input / output requests to a processing device from a plurality of processing programs,
The processing program includes a processing time required for processing in the processing device, an end time that is a time at which the processing is to be ended, and a priority designation that is specified when input / output is given priority over other input / output. An input / output requesting means for making an input / output request to the processing device;
The input / output request is calculated from the reception time received from the processing program when the priority is specified , and the input / output request is specified as the input / output request when the priority is not specified. has been the processing time and end time or al, the start time setting means calculates and sets the start time of the input output request,
Registration means for registering the input / output requests in a queue in the order of the start times calculated by the start time setting means;
Processing control means for fetching the I / O request registered in the queue and passing it to the processing device;
With
The processing control means includes
Taking the I / O requests out of the queue in order of the start times;
When the input / output request is taken out from the queue, if the current time when the input / output request is taken out does not exceed the start time set in the input / output request, the input / output request is sent to the processing device. Hand over,
When the current time has passed the start time set in the input / output request, for the input / output request registered in the queue, the reception time of the input / output request, the start time, and the current time A delay is calculated from the I / O request with the maximum delay is taken out of the queue and passed to the processing unit;
A computer system characterized by that.   4. The computer system according to claim 3, wherein the degree of delay is based on a value obtained by dividing a difference between the current time and the start time by a difference between the current time and the reception time. Computer
Specify the processing time required for processing in the processing device, the end time that is the time at which the processing should be terminated, and the priority designation that is specified when input / output is given priority over other input / output. Input / output request means for making an input / output request to the processing device;
The input / output request is calculated from the reception time received from the processing program when the priority is specified , and the input / output request is specified as the input / output request when the priority is not specified. has been the processing time and end time or al, the start time setting means calculates and sets the start time of the input output request,
Registration means for registering the input / output request in a queue in the order of the start times set by the start time setting means;
Retrieving means for retrieving the input / output requests registered in the queue in order of the start time;
When the I / O request is taken out from the queue by the take-out means, if the time when the I / O request is taken out does not pass the start time set in the I / O request, the I / O request is Processing start means to be passed to the processing device;
When the fetching means fetches the I / O request from the queue, if the current time when the I / O request was fetched has passed the start time set in the I / O request, it is registered in the queue With respect to the input / output request, the delay is calculated from the reception time and start time of the input / output request and the current time, and the input / output request with the maximum delay is taken out from the queue and sent to the processing device. Selection processing start means to be passed,
Computer program to make it function.

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