JPH0492926A - Precedence control processing method - Google Patents

Abstract

PURPOSE:To improve processing efficiency by dynamically and automatically deciding the execution precedence of a computer program which can generate execution objects which can be executed in parallel and reducing the execution objects waiting for the realization of an executable condition. CONSTITUTION:A pointer for linking to a scheduling queue, a pointer for the definition of a predicate and a variable pointer instructing respective variables of an argument are provided for continuous areas for respective goals. Furthermore, a value undecided field showing the presence or absence of the instructed variable is provided for the terms of respective variable pointers for easily and efficiently executing control, and an initial value is turned on so that the value is shown to be not decided. For executing the program in a processor, the goals are executed as mentioned. When the new goal is produced, the control information block of the goal is produced, the execution precedence of the goal is decided by the prescribed processing and the control information block is connected to the scheduling queue of the precedence. Thus, the order of execution is controlled. Consequently, the processing can efficiently be proceeded.

Description

[Detailed Description of the Invention] [Summary] Regarding processing of execution priority of a computer program that can generate execution targets that can be executed in parallel, execution priority is dynamically and automatically determined to satisfy executable conditions. The purpose of this program is to provide a priority management processing method that can reduce the number of execution targets waiting for a goal and improve processing efficiency. Search for the clause whose head matches the goal and whose logical expression of the guard is true, and process the clause to set the value of the required variable and generate a new goal. is determined by the presence or absence of a value for each variable that is an argument of the goal, and the existence or nonexistence of the goal that cannot be executed because the value of the logical expression of the guard containing the variable is not true. The execution priority of the goal is determined based on a predetermined condition, and the goal is executed in a predetermined order according to the execution priority.

[Industrial Application Field] The present invention relates to a priority management processing method for dynamically determining execution priority in executing a computer program that can generate execution targets that can be executed in parallel.

[Conventional technology]

For example, GH, which is one of the well-known programming languages,
A C (Guarded Horn C1ause) language program generally consists of a plurality of clauses, and each clause is structured like a head-knee-guard body.

Here, the head is a predicate, the guard is a logical expression (including a true list value) whose value is a truth value, and the body is a predicate, an assignment expression, or a sequence thereof.

A predicate has the form ``predicate name'' or ``predicate name (variable, variable 1-'I variable)''.The following are examples of three clauses that form part of such a program.

a knee true b(X, Y), c(X, Y
+Z).

b (X, Y) knee true I X=1+Y・2
゜c(X, Y, Z) Knee X=I Z=X+Y.

Such a GHC program is executed as follows.

That is, given a goal consisting of a predicate, search for a clause whose head has the same predicate name as the goal, and when the logical expression of its guard is true, execute the assignment expression of its body, and The predicate is set as a new goal, and the goal consisting of such processing is executed for successively generated goals.

For example, in the program example above, when goal a is executed, goals b (X, Y) and ccX, Y, Z) are generated from the first clause.
is generated. However, in this case, the goal c (
The execution of the goal b(X, Y) results in the execution of the goal b(X, Y) because there is a discriminant The process waits until the body of clause 2 is processed and variable X has the value 1.

Multiple generated goals can be executed from any one unless otherwise specified, and if an execution priority is specified, they will be executed in the order according to the specification, and goals with the same priority will be executed if the environment is possible. They can be executed in parallel.

Generally, when a practical program consisting of many nodes is executed, a large number of goals are generated one after another, so in the program processing unit, these goals are connected to scheduling queues with multiple execution priorities. The goals are taken from the queue in descending order of their value and attempted to be executed.

If the goal requires waiting for execution as described above, connect the variable that caused it to the interrupt chain, and instruct the interrupt chain from the control information corresponding to the variable. The variable hooks (
hook)

Figure 4 shows the above scheduling queue and
It is a diagram illustrating the state of an interrupted chain, and each element connected to the queue and chain is information about each goal, including a pointer to the predicate definition of the goal, a pointer to each variable of the predicate argument, and pointers for chaining, etc., and are configured in each continuous area.

[Problems to be Solved by the Invention] In the above, it is important for processing efficiency to execute goals in an appropriate order so as to reduce the number of goals that lead to interrupted chains. For example, in the example above, the goal b(χ,
If you execute Go71.Y) first, no hook will occur, but if Go71. If you try to execute it before b(X, Y), an interrupt chain will be connected to variable X, χ will turn into a hook, and then when the value of .

However, the execution priority of each goal is given by the program creator writing a specification directly in the program when necessary, so the program creator must decide the priority by taking processing efficiency into consideration. It is extremely difficult to accurately predict the execution situation and determine an appropriate execution priority, which increases the burden on programming.The present invention dynamically changes the execution priority. The object of the present invention is to provide a priority management processing method that can automatically determine execution conditions, reduce the number of execution targets that wait for the fulfillment of executable conditions, and improve processing efficiency.

[Means to solve the problem]

FIG. 1 is a process flowchart showing the configuration of the present invention.

The diagram shows the configuration of a priority management processing method, which is a program consisting of one or more nodes, each node has a head and a guard, and when a goal is executed, the head becomes the node that matches the goal. , and the logical expression of the guard is true, and by processing the clause, setting the value of the required variable and generating a new goal, in processing step 1 For each variable that is an argument of a goal, identify the state of the variable that indicates whether the variable has a value or not, and whether the goal cannot be executed because the value of the logical expression of the guard containing the variable is not true. , In processing step 2, the execution priority of the goal is determined based on a predetermined condition determined by the states of all variables, and the goal is executed in a predetermined order according to the execution priority.

[For production]

According to this processing method, for the generated goal, the state of each variable of its argument is identified and divided into, for example, a state where the value is simply undetermined, a state where it is hooked, and a state where it has a value, and For example, if the values are all determined, the highest priority is given to the status of all variables, and the one with the least number of undetermined variables is given priority, and the undetermined variables are hooked variables. The execution priority is set to give priority to cases where there is. In this way, if all variables have values, the execution of the goal will not be interrupted, and if a goal has one undetermined variable, the value of that variable may be determined by executing it. Since there are many variables, the probability of interruption is low, and if a variable whose value is determined in this way is hooked, a goal will be created to solve the interruption condition by determining the value, and the process can proceed efficiently.

〔Example〕

FIG. 2 is an example of the configuration of a control information block for each goal when implementing the present invention, and as in the past, a pointer for chaining to a scheduling queue and a pointer to a predicate definition are provided in a continuous area for each goal. , and variable pointers that indicate each variable of the argument are provided.In order to control the present invention smoothly and efficiently, each variable pointer section contains information indicating whether or not the indicated variable has a value. A value undetermined field is provided to indicate whether the value is undetermined, and the initial value is turned on to indicate that the value is undetermined.

The area pointed to by the variable pointer includes an area for holding variable values, a control information area indicating the presence or absence of a value, and an area for a pointer to an interruption chain when hooking.

In order to process the program in the processing device, when a new goal is generated by executing the goal as described above, a control information block for the goal as shown in Fig. 2 is created, and the control information block for the goal is created by the processing shown in Fig. 3. The order of execution is managed by determining the execution priority of a goal and connecting control information blocks to the scheduling queue of that priority.

Also, for goals that were interrupted while trying to execute them and were chained to the interruption chain as described above, when the value of the hooked variable is determined, the execution priority is determined and scheduled in the same way as shown in Figure 3.・Connect to queue.

The process shown in FIG. 3 is based on an example in which four levels of execution priority are provided from the first highest priority to the fourth priority, and hook and undef are used as state evaluation variables.

In FIG. 3, first, in processing step 10, hook and undef are set to O, and then each term of the variable pointer of the control information block of the goal to be processed is sequentially processed,
In processing step 11, it is determined whether the value undetermined field is on, and if it is off, the process immediately proceeds to the next variable section via processing step 17, but if it is on, the following processing is performed according to the state of the variable indicated by the variable pointer. do.

In processing step 12, whether a variable is hooked is determined by whether the pointer corresponding to the variable points to an interrupted chain, and if hooked, the value of the state evaluation variable hook is incremented by 1.

If it is not hooked, it is determined whether the variable has a value in processing step 14, and if the value is undetermined, the state evaluation variable undefO value is incremented by 1 in processing step 15, and if there is a value, processing step In step 16, the value undetermined field of the variable pointer term is set to OFF.

After repeating the above processing for all terms of the variable pointer identified in processing step 17, execution priorities are assigned using the values of the state evaluation variables hook and undef as follows.

First, in process step 18, the book and unde are identified.
If the sum of f is 0, that is, both are O, and all variables have values, in processing step 19, the queue is connected to the highest first priority scheduling queue.

Otherwise, process step 20 identifies and hoo
If k=1 and undef=o, that is, there is one variable whose value is not determined and it is hooked, process step 2
1 connects to the second priority queue.

Furthermore, if this is not the case, un
If there are two or more variables with undef=0, that is, values whose values have not been determined, and they are all hooked, connect them to the third priority queue in processing step 23. For goals that do not enter the goal, processing step 24
Connects to the fourth priority queue, which is the lowest, and ends the allocation of execution priorities.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in executing a computer program that can generate execution targets that can be executed in parallel, the execution priority is dynamically and automatically determined, and the execution waits for the fulfillment of an executable condition. This has a significant industrial effect of reducing the number of objects to be executed and improving processing efficiency.

[Brief explanation of drawings]

Fig. 1 is a flowchart of processing showing the configuration of the present invention, Fig. 2 is an explanatory diagram of a goal control information block, Fig. 3 is a flowchart of processing of the present invention, and Fig. 4 is an explanatory diagram of scheduling queues, etc. It is. In the figure, 1.2.10 to 24 are processing flowcharts showing the configuration of the present invention. 1. V. An explanatory diagram of goal control information blocks. 2. A national policy diagram for explaining scheduling, queues, etc.

Claims (1)

[Scope of Claims] A program consisting of one or more sections, each section having a head and a guard, wherein execution of a goal causes the head to match the goal, and the guard When setting the value of the required variable and generating a new goal by searching for the clause for which the logical formula is true and processing the clause, for each variable that is an argument of the goal, , determines the execution priority of the goal based on a predetermined condition determined by the presence or absence of the value of the variable and the existence of the goal that cannot be executed because the value of the logical expression of the guard containing the variable is not true (1 , 2) A priority management processing method, characterized in that the goal is executed in a predetermined order according to the execution priority.