JP2003084990A - General communication method between task - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve portability and reliability by reducing a labor for designing inter-task communication, providing a flexible synchronized control design and a strict heap memory control, and standardizing inter-task communication procedures in the development of a computer system using a built-in OS or a general purpose OS. SOLUTION: The inter-task communication and an interface are designed as an integrated one, (1) the inter-task communication is materialized by a message or a message address communication function alone, (2) the synchronized control is commanded by a transmission side and a receiver side synchronously responds thereto using the message or the message address communication function according to the command, and (3) the heap memory control is commanded by the transmission side by acquisition and release (return).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to inter-task communication design, which is an important element in computer system development using an embedded OS or a general-purpose OS.

[0002]

2. Description of the Related Art In a computer system development using a built-in OS typified by a real-time OS and a general-purpose OS such as Windows (registered trademark) and Unix (registered trademark), designing communication between tasks is an important element. The issue that must be investigated / considered is OS
It is summarized in the communication function, synchronization control method and resource management function provided by.

[0003]

In the past, every time the OS was changed, the macro function provided by the new OS was used, and the communication method between tasks, and the design and interface of the control method, which is the above-mentioned problem, were used. Had been redesigned.
Therefore, due to the labor required for redesign, the effect of porting tasks, and the like, a huge amount of work has been required to change the OS.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. When the requirements specifications for inter-task communication are examined and examined, various macros provided by the OS are also found. Regardless, the truly required functions are extremely limited, and most kinds of OS provide such functions. Therefore, on the premise that the same high-level language is used, if the functions to be used are narrowed down as much as possible and the inter-task communication method or interface is configured using only necessary and sufficient functions, the user macro (or function)
Only by rewriting, will porting be easier. On the other hand, in inter-task communication in an embedded OS or a real-time multi-task system, there are technical constraints such as critical timing and severe memory resources, and it is necessary to design in consideration of this problem. In particular, synchronous control and dynamic memory (heap memory) management are essential functions. The functions required for inter-task communication can be summarized into the following three points. It is realized using only general communication functions provided by various OSs. Controls synchronous communication (whether or not synchronization is required, synchronization method and dynamic control). Performs heap memory management (whether management is required or not, and dynamic control).

In order to meet the above-mentioned required specifications, communication between tasks and an interface (hereinafter referred to as I / O
(Referred to as F) is designed as a single unit to realize a general-purpose communication method between tasks. Inter-task communication is realized only by a message or message address communication function. It is assumed that the sender controls the synchronization control, and the receiver uses the message or message address communication function to send a synchronization response in accordance with the instruction. This I / F includes a response destination of this synchronous communication and control information for instructing the necessity / unnecessity of the synchronization, and thereby realizes the necessity / unnecessity of the synchronization, the synchronization method, and the dynamic control. Heap memory management shall be instructed by the sender and shall be performed by acquisition and release (return). This I / F includes this heap memory information and control information for instructing the necessity / unnecessity of the release, whereby the necessity / unnecessity of the heap memory management,
And realize dynamic control.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a general communication method between tasks according to the present invention will be described below with reference to the drawings. FIG. 1 shows an example of inter-task communication with synchronization control, FIG. 2 shows an example of inter-task communication without synchronization control, and FIG. 3 shows an example of handler-to-task communication without synchronization control and memory management.
FIG. 4 shows an example of inter-task communication for making a reception request. Table 1 shows an example of a general-purpose communication interface between tasks.

[0007]

[Table 1]

FIG. 1 shows an example of inter-task communication with synchronization control. It is assumed that the transmission side instructs the synchronization control, and the reception side is configured to perform a synchronization response using the message or message address function in accordance with this instruction. The processing flow is as shown in. Further, FIG. 2 is an example of communication between tasks without synchronous control, and the flow of processing is
As shown in.

This I / F can be adopted not only for inter-task communication but also for handler-> inter-task communication. An example of handler-> inter-task communication without synchronous control and memory management is as shown in FIG. The processing flow is as shown in. Further, an example of communication between tasks for making a reception request is as shown in FIG. 4, and the flow of processing is shown in.

[0010]

As described above, according to the general-purpose communication method between tasks according to the present invention, it is understood that the following effects can be obtained. Flexible Synchronous Control Design Synchronous control is a critical issue in the design of real-time multitasking systems, and it is a part where design changes often occur during production and testing, but the I / F according to the present invention is adopted. By doing so, the specification of this part can be easily changed. For example, assuming that the sending side task and the receiving side task were originally designed without a synchronous response, if the specification is changed to wait for a synchronous response, the transmitting side task sets the mailbox ID for synchronization of this I / F. This is because the procedure / specification can be changed simply by performing. If a mailbox waiting for a synchronous response is set as the normal mailbox of the sending task, the task will be activated by the logical sum of the synchronous response wait and the normal event wait. On the other hand, if a mailbox that waits for a synchronization response is set as the synchronization mailbox for the sending task, strict synchronization control can be performed. In addition, the dynamic control of the synchronous control is realized by determining whether the task on the sending side specifies the mailbox waiting for the synchronous response at that time and selecting whether the synchronous control is necessary or not as necessary. To do. Strict heap memory management In the past, heap memory management decided how to acquire / release between tasks each time it was designed, and created according to it, but heap memory release (memory leak) and Errors such as multiple release were incessant. Book I / F
The procedure of releasing the heap memory becomes stricter by adopting, and the reliability can be improved by making the processing into a library and making the releasing procedure common. Conversely, by not specifying heap memory management, it is possible to use other than heap memory (static memory). Further, the dynamic control of the heap memory management is realized by the task on the transmission side judging the method of memory management at that time and selecting the necessity / unnecessity of the memory management as necessary. As mentioned in the standardization of inter-task communication procedure, when designing inter-task communication so far, each time (communication, I / F) macro selection,
Although it was necessary to negotiate in advance the method of synchronous control, the method of controlling heap memory, etc., by adopting this I / F, it is possible to standardize intertask communication while ensuring versatility. This interface can be used not only for inter-task communication but also for handler-to-task communication. As a result, on the task side, activation by multi-event (logical sum) can also be performed by the handler. In addition,
Here, the handler means general interrupt processing. High portability and high reusability In recent years, it has become common for program development to be performed using a compiler. Taking the C language as an example, there is a "struct" as one of the data structure description methods of the C language. When this I / F is described by this "structure", the order in which the items handled by the application program and the library are arranged, the type and size of the data do not need to be changed. Therefore, the designer can flexibly design the I / F structure as long as the basic items are covered, which shows high portability and high reusability. High reliability and high productivity is nothing but to build a highly reliable library / module that has a proven track record of use by accumulating a track record of adoption, which means that many tasks can be reused. It will facilitate and increase programming productivity.

[Brief description of drawings]

FIG. 1 shows an example of inter-task communication with synchronous control.

FIG. 2 is an example of communication between tasks without synchronous control.

FIG. 3 shows an example of communication between a handler and a task without synchronous control and memory management.

FIG. 4 is an example of communication between tasks that makes a reception request.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiro Ishikawa             1-9-9 Motomoto-cho, Hachioji-shi, Tokyo             Chuo Electronics Co., Ltd. F term (reference) 5B098 AA03 GA04 GC16 GD03 GD14

Claims (3)

[Claims] 1. The inter-task communication is realized by using only the message or message address communication function provided by various OSs, and the inter-task communication and the interface are integrally designed to control the synchronous communication and the heap memory management. A general-purpose communication method between tasks, characterized in that 2. The synchronous communication is controlled by the transmitting side, and the receiving side uses the message or message address communication function to make a synchronous response in accordance with the instruction from the transmitting side, and a synchronous communication response destination and a necessary point. The general-purpose communication method between tasks according to claim 1, wherein the necessity / non-necessity of synchronization, the synchronization method, and the dynamic control are realized by the interface including the control information indicating the unnecessary. 3. Heap memory management shall be instructed by the transmitting side, and heap memory management is performed by acquisition and release (return) instructions, and heap memory information and control information instructing whether release is necessary or not are also included. The general-purpose communication method between tasks according to claim 1, wherein heap memory management is required / not required and dynamic control is realized by an interface.