JP2003050708A - Method for determining order of job execution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently shorten time required for execution of the overall target job in a computer system, by which a plurality of jobs are executed in parallel. SOLUTION: A computer 101 accepts history information of files accessed, during execution of the jobs by every job from the outside and determines the order of execution of the jobs so that a second job is executed before a first job, when the second job inputs data to the file referred to during the execution of the first job, based on the history information to determine the execution order between mutual jobs to require reference of a prescribed file during the execution of the jobs in a certain system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of determining a job execution order in a computer system in which a plurality of jobs can operate in parallel, and in particular, effective job execution when moving to a computer system having a different configuration. Regarding the order determination method.

[0002]

2. Description of the Related Art Conventionally, in online processing for large-scale banking systems and online processing for managing merchandise in the distribution industry, many operations are carried out in order to improve customer service. The online processing is accompanied by batch data processing (batch processing) for totaling the data handled in the business. As the amount of online processing increases and the types of online services diversify, the amount of batch processing is increasing and the processing content is becoming more complicated. Generally, a job that performs online processing is called an online job, and a job that performs batch processing is called a batch job. In order to cope with these increasing jobs, there is a tendency to construct a computer system having a plurality of CPUs and execute batch jobs in the system.
As a system construction method having a plurality of CPUs, there is a system (tightly coupled multiprocessor system) in which a plurality of CPUs share one main storage device and operate with one operating system (OS). As another system construction method, there is a system (loosely coupled multiprocessor system) in which a plurality of computers having independent CPUs and main storage devices are coupled by an inter-channel coupling device or the like.

In the system using both of the above construction methods, it is necessary to organize an efficient job schedule so that batch processing can be completed in a short time. In particular,
In a loosely coupled multiprocessor system, multiple independent O
Since S operates, it is necessary to perform business while the OSs cooperate with each other. Therefore, as a conventional method for efficiently performing batch processing, Japanese Patent Laid-Open No. 17380/1993
There is one disclosed in Japanese Patent Laid-Open No. 7 and Japanese Patent Laid-Open No. 6-68052. These two cases relate to a job distribution method in which resource utilization is dynamically measured and scheduling is performed so as to equalize loads on a loosely coupled multiprocessor system. That is, the above-mentioned JP-A-5-173807.
The technique disclosed in Japanese Patent Laid-Open Publication No. 2003-242242 is provided with a resource load measuring means for measuring the resource load amount of the system at regular time intervals and dynamically changing the job execution multiplicity according to the measurement result. Further, the one disclosed in Japanese Patent Laid-Open No. 6-68052 is related to a function of automatically allocating a job to the processor with the least load by providing a processor usage rate monitoring unit for measuring the usage rate of the processor at a constant time interval. It is a thing.

[0004]

As described above, in recent years, batch processing has become complicated due to diversification of business and increase in data amount. As a method for shortening the job processing time, a means of increasing the CPU performance of the computer or highly multiplexing the entire job can be considered. However, the current technology has almost reached its limit in improving the former single CPU performance, and it is considered certain that the latter will require high multiplexing in the future. However, in order to achieve high multiplexing of batch jobs without breaking the correlation of these complicated batch jobs, efficient use of the computer resources of the multi-processor system is required unless the efficiency of job scheduling is increased. It doesn't. 2 above
The prior art described in one of the publications determines job scheduling dynamically during job execution on an already constructed system. This is to improve the efficiency of scheduling for a single job when the job is executed, and not to measure the entire job and improve the efficiency of scheduling.
Further, these conventional techniques are applied when a job is executed in an already constructed system, and cannot be used for the job scheduling evaluation in advance when the system configuration is changed.

While an online job is a time-dependent job, a batch job, which is a batch data process, has the property that it does not depend on the start time at which certain processing is performed on a fixed input file. For such a job in which a plurality of jobs are periodically repeated, it is possible to predict the subsequent job execution based on the past job execution history. By performing a job scheduling plan before executing a job of this nature, it is possible to expect a reduction in the overall processing time. In addition, by performing the above-mentioned job scheduling plan when designing the system, it is possible to make a file allocation plan for the disk device, etc., and perform job scheduling evaluation in advance when changing the system configuration. You can

The present invention is directed to improving the efficiency of batch job scheduling and has the following three objects. A first object of the present invention is to provide a job execution order determination method capable of supporting efficient job schedule planning based on past execution history before executing batch processing. is there. A second object of the present invention is to provide a job execution order determination method capable of estimating the effect before the change based on the past execution history when the system operation such as the job multiplicity is changed. To provide. A third object of the present invention is to reduce the frequency of access to a disk connected to another computer in the above system when distributing jobs on a loosely coupled multiprocessor system, and to keep overhead related to data transfer low. Therefore, the computer that executes each job is based on past history information so that the files accessed by the distributed jobs can be placed on the disk connected to one computer in the above system. It is to provide a job execution order determination method capable of determining the job execution order.

[0007]

In order to achieve the above-mentioned object, the present invention is a method for determining the execution order between jobs which requires reference to a predetermined file during job execution in a system in a computer. Therefore, the computer receives, from the outside of the computer, history information of a file accessed during job execution for each job, and based on the history information, a file referred to during execution of the first job is received. On the other hand, when the second job inputs data, the execution order of the jobs is determined so that the second job precedes the first job. Further, the computer receives parameters relating to the resources of the system from outside the computer, receives from the outside of the computer, for each job, history information of a file accessed during job execution, the parameters and the history information. It is also characterized in that the execution order of the jobs is determined based on

[0008]

According to the present invention, the execution start condition of each job is determined from the collected access history information, and the execution time of each job is obtained from the execution history information to obtain the job execution start time based on the current job execution. be able to. Then, the job multiplicity in the computer system to be simulated is the maximum number of jobs that can be operated in parallel, and the second condition that the execution start condition is followed by the simulation. , Virtual job execution that does not depend on the job scheduler can be reproduced. From this simulation result, it is possible to present a job schedule plan that can reduce the processing time.

When a system operation change such as an increase / decrease in job multiplicity is given as a parameter, the parameter is added to the above-mentioned execution start condition to obtain a job schedule result when the operation change is made. Can be provided. As a result, the system can be reconstructed after obtaining an estimate to solve the problems in the current system. Also,
By grouping jobs based on the files to be accessed before the simulation, the job schedule result under the new system condition given as a parameter can be provided. As a result, it is possible to provide a job schedule proposal on a system having a configuration different from the current system such as the loosely coupled multiprocessor system. As described above, the static evaluation using the execution history makes it possible for the present invention to obtain a quantitative evaluation regarding the job schedule without using an actual machine, that is, without burdening the target system.

[0010]

Embodiment In this embodiment, one or more CPUs, and
The target is a computer system composed of one or more computers having disks accessed from the CPU. When the computer system is composed of a plurality of computers, each computer shall have means for communicating with each other. In the above computer system, a plurality of jobs are executed in parallel. Here, there is an upper limit to the number of jobs that are executed in parallel, and the upper limit is called the job multiplicity. A job is composed of one or more job steps. Here, the job step corresponds to one of the programs executed in the job. read, w
A file that has been subjected to operations such as write and reference is called an access file in this case. The batch job can be logically executed as long as the referenced file is generated. Therefore, when a file accessed by a job is accessed by another job, it is necessary to start execution after the other job is completed. A job that a job should start after completion of execution is called a scheduling condition.

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the basic system configuration of an embodiment of the present invention. In this embodiment, the computer 10
Reference numeral 1 is composed of a CPU 102 and a memory 103. Parameter information 114, which will be described later, is stored in the memory 103.
A job scheduling analysis unit 1 that inputs a job execution history 115 and a job scheduling analysis
04, system operation history collection unit 110 for collecting system operation history, and job schedule program 1
11, and the job schedule program 111 includes a job activation unit 112 and a registration creation unit 113.
It consists of The processing in each of these parts is CP
It shall be executed by U102.

A job registered in the computer 101 is registered in the registration list creating unit 11 in the job schedule program 111.
3 is registered in the job register 117. The job activation unit 112 activates the job based on the job registration list 117 created by the above procedure and puts it in the execution state. To activate the job, a job control statement 118 that describes which program is executed by the job to be activated and which file to access must be prepared for each job. Based on this job control statement 118, the job activation unit 112 confirms whether resources such as files necessary for executing the job are secured, and then activates the job.

The job is put into the execution state by the above procedure.
The system operation history collection unit 110 collects the execution status and creates a job execution history 115. A configuration example of the job execution history 115 is shown in FIG. As the execution history data to be collected, as shown in FIG.
15-1, job step start record 115-2, file close record 11 for access file
5-3, job step end record 115-4, job end record 115-5 and the like. Each of these records is generated by an event such as the start of job execution, file closing, etc., and the record type that indicates what event caused the record is included at the beginning or inside of these records. There is. In this embodiment, the job start record is 01, the job step start record is 02, and the file close record is 0.
It is assumed that the description about the record type in which the job step end record is 04 and the job end record is 05 is at the beginning of each record.

Each record, which is the job execution history data shown in FIG. 2, will be described in more detail. The job start record 115-1 includes the record type 01,
The job step start record 115-2 has a job name, a job start date, and a job start time. In addition to the record type 12, the job step name, the job step start date, the job step start time, and the job that issued this record. The file close record 115-3 that has a name and has an access file includes a file name, a file close date, a file close time, a job step name that issued this record, and a job name that issued this record, in addition to the record type 03. The job step end record 115-4 has a record type 04,
It has a job step name, a job step end date, a job step end time, and a job name that issued this record. The job end record 115-5 has a job name, a job end date, and a job end time in addition to the record type 05. , CPU usage time.

Parameter information 1 input to the job scheduling analysis unit 104 together with the job execution history 115
The structure of 14 is shown in FIG. The parameter information 114 is data related to jobs, other than the job execution history 115 shown in detail in FIG. 2, the number of spaces (maximum job execution multiplicity) required for simulation, the CPU performance ratio (CPU of a new system). Performance improvement ratio) and all information such as output result specification. Figure 3 shows 30 spaces
CPU performance ratio 1 (for CPUs with the same performance), grouping ON (when grouping function is enabled),
.. indicates the case.

Next, details of the job scheduling analysis unit 104, which is a feature of the present invention, will be described. The job scheduling analysis unit 104, as shown in FIG.
The job data analysis unit 600 that analyzes the execution history data 115 (see FIG. 2) described above, the parameter information 11 described above.
4 (see FIG. 3) to simulation condition definition information (114-1 in FIG. 5) that is information necessary for simulation.
A parameter analysis unit 700 for creating a job, a job grouping unit 800 for performing a job grouping on the data created by the job data analysis unit 600, and a simulation unit 900 for simulating the execution status of the job by these input data. The job scheduling analysis unit 104 and the system operation history collection unit 110 are provided in the same system in this embodiment, but may be provided in different systems.

The result analyzed by the simulation unit 900 is output from the simulation unit 900 as a simulation result 116. An example of this simulation result 116 is shown in FIG. As the output information, as shown in the figure, temporal transition 116-1 of job execution multiplicity after simulation, list 116-2 of executed jobs, and the like are listed. In the execution job list 116-2 of FIG. 4, the execution jobs of the space 1 are JOB1 and J.
In OB5 and JOB3, the job executed in space 2 is JOB
2 and JOB8, for example, JOB1 is 7:00.
Through 7:45, the execution time is 45 minutes. It is also possible to include resources used for each job in the list of executed jobs.

Next, the job scheduling analysis unit 10
A detailed explanatory view of No. 4 is shown in FIG. Job data analysis unit 6
00 creates an information cell 200, which is an information unit used for simulation in the present invention, from the job execution history 115. The information cell 200 is roughly classified into a job information cell 201, a job step information cell 202, and a file information cell 203 according to the type of history included in the job execution history 115 as shown in the information cell configuration example of FIG. To be done.
The information cell 200 has a table structure, and an element (pointer) therein points to a related information cell so that the entire information cell has a list structure. The job information cell 201 indicates a list of job step information cells 202 that make up the job. Further, the job step information cell 202 is the file information cell 2 of the file accessed in the job step.
Refers to 03. These form one set and represent the entire information of the job. Since the job execution history 115 includes a plurality of jobs to be analyzed, the job information cell 201
The self itself also has a list structure, and is constructed so that pointers sequentially point to the next job information cell 201.

Next, a more detailed table structure of each of the above information cells will be described with reference to FIGS. The information contained in the execution history is stored in each information cell as necessary, together with the information for forming the list structure of the information cell. FIG. 7 shows the table structure of the job information cell 201. In the figure, a pointer 301 points to the next element in the list of job information cells.
The pointer 302 points to the beginning of the list of information cells of the job steps that make up the job. Further, 303 is a job name for identifying a job, 304 is a job start time, and 305 is an area for storing a job end time. These areas are used when the simulation unit 900 obtains execution conditions. Also, 30
An area 6 stores the total CPU usage time used by the job.

FIG. 8 shows the table structure of the job step information cell 202. In the figure, a pointer 40
Reference numeral 1 indicates a next element (job step information cell) in the job step information cell list, and the pointer 402 points at the head of the information cell list of the file accessed in the job step. Reference numeral 403 is an area for storing a job step name for identifying a job step, and 404 is an area for storing a program name executed by the job step. FIG. 9 shows the table structure of the file information cell 203. In the figure, a pointer 501 is for pointing to the next element (file information cell) in the list of file information cells. Reference numeral 502 is an area for identifying a file and storing a file name used when the simulation unit 900 obtains an execution condition.

Next, the processing flow of the job data analysis unit 600 will be described in detail with reference to the flowchart of FIG. First, the top data is read from the job execution history 115, and the processes of steps 602 to 606 are continued until the data of the job execution history 115 becomes empty (step 601). When a record that does not contain the information cell for storing the contents of the record in the information cell list until the record is read, such as a job start record, is read, an information cell that newly stores the contents is created. There is a need to. It is determined whether or not the read data of the job execution history 115 is the record type for which these new information cells should be created (step 602).

If the determination in step 602 above is true, whether the record is a job or a job step,
Alternatively, it is determined from the contents of the record whether or not it is related to a file, an area of the information cell of the corresponding format is secured (step 603), the data is stored in the area, and at the same time, from the list for the new information cell. Information for forming the list structure such as pointer setting is set (step 604). If the determination in step 602 above is false, the data is stored in the corresponding information cell among the information cells created before that (step 605). After that, the process returns to the determination step 601 for the processing of the next data of the job execution history 115 (step 606).

The parameter analysis unit 700 analyzes the parameter information 114 as shown in FIG. 3 to create simulation condition definition information 114-1 which is a condition for simulation. Next, the processing of the parameter analysis unit 700 will be described in detail with reference to the flowchart of FIG.
First, a parameter is read from the parameter information 114, and the processing shown in steps 702 to 703 is continued until the parameter becomes empty (step 701).
Which parameter the read parameter information is is determined and reflected in the simulation condition definition information 114-1 according to the type of the parameter (step 702).
For example, from the parameter information 114, the multiplicity with which the job is executed is read as the number of spaces and set in the corresponding item in the simulation condition definition information 114-1. In order to continue the process, the process returns to the judgment step 701 for the next parameter information 114 (step 70).
3).

The job grouping unit 800 is used to obtain the result of job grouping focusing on the locality of file access in consideration of a loosely coupled multiprocessor system different from the current system. By the processing of the job grouping unit 800, the list of job information cells 201 is divided into groups of information cells of jobs whose files to be accessed are duplicated and grouped. By performing simulation by the simulation unit 900 in units of job groups created by the job grouping unit 800, it becomes possible to obtain scheduling analysis results for a job group in which duplication of accessed files is eliminated or reduced.

Next, the processing of the job grouping unit 800 will be described in detail with reference to the flowchart of FIG.
First, the simulation condition definition information 114-
The table data that specifies whether to group the jobs in 1 is referred to, and when it is specified that the grouping is performed, the following steps 802 to 8 are performed.
The process of 04 is performed, and the process is terminated without performing other processes (step 801).

If it is specified in step 801 that grouping is to be performed, first, the read operation of the job information cell 201 is performed, and the processing of the following steps 802 to 804 is performed to empty the list of the job information cell 201. It continues until it becomes (step 802). Jobs that access the same file as the job represented by the job information cell read in step 802 are sequentially searched from the list of job information cells, and these jobs are regarded as the same group and grouped. Further, the jobs that access the same file as the jobs in the same group here are also in the same group (step 80).
3). Target the next job information cell (step 80
4) Then, returning to step 802, the same processing is performed again.

Next, the procedure of the job execution simulation in the simulation section 900 will be described in detail with reference to the flowcharts of FIGS. 13 and 14. 14
13 schematically illustrates the reconnection of the list of the job information cells 201 performed in FIG. In FIG. 14, 201-j (j = 1 to j) represent job information cells having different contents. FIG. 15 shows an example of the table structure of the space 1001 in FIG. In the table structure of the space 1001 shown in FIG. 15, the pointer 1101 indicates the next space 1001.
It is for pointing at 1. Also, pointer 1
Reference numeral 102 is for pointing to the beginning of the list of job information cells connected to the space 1001.

Next, the operation of the simulation section 900 will be described in detail with reference to the flowchart of FIG. First, information is read from the simulation condition definition information 114-1. Simulation condition definition information 114
The following steps 902 to 903 are performed until -1 becomes empty (step 901). When the simulation condition definition information 114-1 is empty, the process proceeds to step 904.

In step 902, processing corresponding to the read simulation conditions is performed. For example, when the parameter is the number of spaces representing the maximum number of job execution multiplicity, the space 1001 of that number is secured in the memory area. If it is the CPU performance ratio, the job information cell 20
The CPU usage time 306 in 1 is converted according to the ratio, and at the same time, the job end time 305 is rewritten (see FIG. 7).

In order to sequentially extract the job information cells 201 from the beginning of the list 1 of the job information cells to be connected,
It is determined whether or not the job information cell 201 exists (step 904). If the job information cell 201 exists,
It is sequentially taken out from the beginning and the processes of the following steps 905 to 911 are performed until it is empty. First, the scheduling conditions of the above jobs such as file transfer with other jobs are obtained (step 905). next,
The time when execution can be started is calculated based on the scheduling conditions obtained in step 905 (step 906). At the time obtained in step 906, the contents of the job information cell list connected to the space 1001 are searched, and it is determined whether or not there is a vacant time at which the execution can be started and the execution is possible (step 907).

If the determination in step 907 is true (executable), the job information cell is connected to the empty space 1001. When the job information cell is connected, the job step information cell pointed to by the job information cell and the like are also connected to the space 1001 (step 908). If the determination in step 907 is false (executable), the job information cell is connected to the space 1001 in which execution can be performed earliest after the execution startable time obtained in step 906 (step 909). . Then, after the connection of the job information cell described above is completed, the data in the job information cell such as the job execution time is rewritten (step 910), and the process returns to the determination step 904 for the next job information cell. In addition,
During the processing in the simulation unit 900, there are times when a job is not executed. By expressing these times with a job information cell indicating that the space is empty, the space 1
Idle time in the job information cell list of 001 can be expressed.

Next, how the job information cell is specifically changed in steps 904 to 911 in the simulation section 900 will be described with reference to FIG. First, in decision step 904, a list of unprocessed job information cells to be connected is referred to. In the case of the example shown in FIG. 14, the unprocessed job information cells are 201-1, 201-2, ..., 201-.
Since i is present, the determination step 904 is YES,
From the top of the list, 201-1, 201-2, ..., 2
01-i are taken out in order, and step 9 is carried out for each.
The processing from 05 to step 911 is performed.

First, the job information cell 2 at the head of the list
In processing 01-1, in step 905 to step 908 or step 909, after which job the job information cell 201-1 is executed in the list of job information cells representing the simulation result on the memory. Figure out what should be done. In the case of the example in FIG.
It shall be executed after the job information cell 201-4. In that case, in step 908 or step 909, the job information cell 201-1 is reshuffled after 201-4. At the same time, the job information cell 201-1 is deleted from the unprocessed job information cell list 200. As described above, in the present embodiment, the execution status of the job is represented as a list of information cells on the memory, and the simulation is performed using the parameter information and the job execution history.

[0034]

According to the present invention, it is possible to obtain a job scheduling plan that can shorten the job processing time in the existing system. Further, the job execution status due to the system configuration change can be grasped before the system configuration change based on the job operating status of the current system. Furthermore, since the simulation is performed based on the job execution history, it is possible to perform the static evaluation without imposing a load on the target system as much as dynamic job monitoring.

[Brief description of drawings]

FIG. 1 is an embodiment of a computer system including a job scheduling analysis unit 104 for realizing a job scheduling analysis method of the present invention.

FIG. 2 is a job execution history 115 that is input information of the present invention.
FIG.

FIG. 3 is an explanatory diagram of parameter information 114 that is input information of the present invention.

FIG. 4 is an explanatory diagram of a simulation result 116 which is output information of the present invention.

FIG. 5 is a job scheduling analysis unit 104 of the present invention.
3 is a specific configuration example of

FIG. 6 is an explanatory diagram showing the configuration of a job and an information cell, which is data related to the job, used in the job scheduling analysis method of the present invention.

FIG. 7 is an explanatory diagram showing a table structure of a job information cell that stores job data.

FIG. 8 is an explanatory diagram showing a table structure of a job step information cell that stores job step data.

FIG. 9 is an explanatory diagram showing a table structure of a file information cell that stores data of an access file.

FIG. 10 is a flowchart illustrating a process of job data analysis unit 600.

11 is a flowchart illustrating a process of a parameter analysis unit 700. FIG.

FIG. 12 is a flowchart illustrating a process of a job grouping unit 800.

FIG. 13 is a scheduling simulation unit 90.
It is a flow chart explaining processing of 0.

FIG. 14 is an explanatory diagram showing a data structure for representing job execution in a simulation.

FIG. 15: Space 1001 used in simulation
It is an explanatory view showing the table structure of.

[Explanation of symbols]

101 ... Calculator, 102 ... CPU, 103 ... Memory, 1
04 ... Job scheduling analysis unit, 600 ... Job data analysis unit, 700 ... Parameter analysis unit, 800 ... Job grouping unit, 900 ... Simulation unit, 11
0 ... System operation history collection unit, 111 ... Job schedule program, 112 ... Job activation unit, 113 ... Registration list creation unit, 114 ... Parameter information, 115 ... Job execution history, 116 ... Simulation result 117 ... Job registration list, 118 … Job control statements.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tadashi Yamagishi             5030 Totsuka Town, Totsuka Ward, Yokohama City, Kanagawa Prefecture             Ceremony Company Hitachi Software Development Division (72) Inventor Shunji Tanaka             1099 Ozenji, Aso-ku, Kawasaki City, Kanagawa Prefecture             Ceremony company Hitachi Systems Development Laboratory (72) Inventor Toshiyuki Kinoshita             1099 Ozenji, Aso-ku, Kawasaki City, Kanagawa Prefecture             Ceremony company Hitachi Systems Development Laboratory F term (reference) 5B045 BB28 BB42 EE16 GG01 KK05                 5B085 AC14 BA01 BC03 BG02                 5B098 GA03 GA10 GC01 GC02 GC09                       GD14

Claims (8)

[Claims] 1. A method for determining an execution order between jobs that requires reference to a predetermined file during execution of a job in a computer, the computer comprising: In the case where the history information of the file accessed during the job execution is received, and the second job inputs data to the file referred to during the execution of the first job based on the history information, Is a job execution order determining method, wherein the execution order of the jobs is determined so that the second job comes before the first job. 2. The job execution order determining method according to claim 1, wherein the computer acquires, in addition to file history information, information regarding a CPU performance ratio of the system. 3. The job execution order determining method according to claim 1, wherein the computer acquires, in addition to file history information, information including information regarding the multiplicity of the system. 4. The job execution history includes information indicating a file transfer relationship between the jobs, and in the step of determining the execution order of the jobs, information indicating a file transfer relationship between the jobs. According to
4. The job execution order determining method according to claim 1, wherein the execution of the jobs is simulated. 5. The job execution order determination method according to claim 4, wherein the simulation of the execution of the jobs includes a step of outputting the simulation result. 6. The jobs that use the same file are grouped into one group based on the execution history of the jobs, and the jobs included in the group are summarized.
The job execution order determination method according to claim 4, wherein a simulation is performed. 7. The job execution order determination method according to claim 1, wherein the system is a system different from the system in which the job is executed. 8. A method for determining the order of execution of jobs in a computer, which requires reference to a predetermined file during job execution in a certain system, wherein the computer is a resource of the system from outside the computer. Accepting a parameter relating to, for each job, accepting history information of a file accessed during job execution from outside the computer, and determining an execution order of the jobs based on the parameter and the history information. A method for determining the job execution sequence.