KR20040102835A - Method for communication of message queue in real time operating system - Google Patents

Abstract

PURPOSE: A message queue communication method in an RTOS(Real Time Operating System) is provided to guarantee always the same performance regardless of the amount of data in a transmission rate. CONSTITUTION: A region of a message queue(100) to be used for communication is created. In this case, a send task(200) obtains an address of an empty message queue pointer(110) by using a queue get. The content of data to be transmitted is directly written in a pointer region(210), and when the data is ready for transmission, it transmitted through a send process. A receiving task(300) receives the data through a receive process. A returned result value corresponds to an address of the message queue pointer(110) plus a size of the actually received data. The receiving task(300) uses the received data through a read process, and if the data is not necessary any longer, the receiving task(300) informs that the message queue pointer region(110) is not necessary any longer by using a queue free, and makes the region free for reuse.

Description

Method for communication of message queue in real time operating system

The present invention provides a real-time operation that can operate without a memory copy process in order to improve message delivery performance in a communication method using a message queue provided by a general real time operating system (RTOS). The method relates to the message queue communication method in the operating system. More specifically, it implements the concept of processing by pointer operation so that the actual memory copy process is not performed. It is an empty queue before the message queue send process. By receiving a pointer of, by writing the data to be sent directly to the message queue, and by receiving a pointer of the received queue at the time of Message Queue Receive, so that the memory copy process does not occur at all, To reduce the load that takes up most of the CPU's execution time. In addition, the present invention relates to a message queue communication method in which a memory copying process is omitted in a real-time operating system to ensure the same performance regardless of the amount of data at a transmission speed that decreases according to the amount of data.

In general, communication methods between processors used in a general operating system (OS) include shared memory, message queues, pipes, and mail boxes. In the mobile communication program, most communication is performed by a communication method using a message queue that facilitates communication between various tasks.

1 is a diagram illustrating a message queue communication process supported by a general RTOS.

As shown therein, a communication method using a message queue includes a message queue, a message queue is created, a send, a receive, and a delete.

First, a message queue 10 to be used for communication is generated through the message queue creation process. Thereafter, the send task 20 to transmit data secures the buffer area with a local variable and then writes the data to be transmitted to the buffer 21.

Meanwhile, when the preparation for transmission is completed, the message is transmitted using a message queue send. At this time, the contents of the buffer 21 in the above process becomes a memory copy at 11.

As described above, the data to be transmitted are sequentially stacked in the message queue 10.

On the other hand, the task (# 0) to receive the message first secures the memory space of the buffer 31 as a local variable. This is the space where the data you want to receive will be stored.

Then use the Message Queue Receive to prepare to receive the message. If there is data to be received in the message queue 10, it is stored in the buffer 31 through a memory copy in the receiving process.

In the communication method using the message queue as described above, a memory copy process corresponding to the corresponding data is present at the time of send and receive.

Therefore, a problem occurs that the speed decreases according to the amount of data to be transferred by the memory copy process, which causes a problem of degrading the performance of the entire system.

Accordingly, the present invention is proposed to solve the above problems of the prior art,

It is an object of the present invention to receive a pointer to an empty queue before a Message Queue Send process, so that the data to be sent can be written directly to the Message Queue, and at the time of Message Queue Receive. By receiving the pointer of the received queue so that the memory copy process does not occur at all, the load that takes up the most of the CPU's execution time can be reduced, and the data rate is always the same regardless of the amount of data. It is to provide a message queue communication method in a real-time operating system to ensure performance.

In the message queue communication method in a real-time operating system (RealTime Operating System) according to the present invention for achieving the above object,

Creating a message queue area to be used for communication through Message Queue Create;

After the message queue is created, acquiring an empty message queue pointer address using a queue get in a send task;

After acquiring the address, writing the content of the data to be transmitted directly to the pointer area, and if the data is ready to be transmitted, transmitting data using a send process;

When the data is transmitted, receiving data directly through a receiving process in a task to receive a message;

Using the received data in the receive task through a read process;

After using the data, it is characterized in that the method consists of a process of freeing the area for reuse of the message after notifying that the message queue pointer area is not necessary by using queue free. .

1 is a diagram illustrating a message queue communication process supported by a general RTOS.

2 is a view illustrating a message queue communication process supported by the RTOS according to the present invention;

3 is a flowchart illustrating a message queue creation process in a message queue communication process according to the present invention;

4 is a flowchart illustrating a message queue send process in a message queue communication process according to the present invention;

5 is a flowchart illustrating a message queue receiving process in a message queue communication process according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100 ..... Message Queue

200 ..... Send Task

300 ..... Receive Task

210, 310 ..... Message Queue Pointer

Hereinafter, a preferred embodiment of the "message queue communication method in a real-time operating system" of the present invention according to the above technical concept will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating a message queue communication process supported by the RTOS according to the present invention.

As shown in the figure, in the message queue communication method according to the present invention, a process of queue get and queue free is added, and a message queue pointer usable through the queue get. In other words, since the address can be known, the buffer 21 region of FIG. 1 can be allocated separately and can be written directly to the pointer 210 region without a memory copy process. Here, the pointer 210 area is the same area as that of the reference numeral 110 of the message queue 100.

In addition, the reception task 300 finally performs a queue-free process so that the use of the area 110 is terminated in the receive task 300 and other send tasks can be reused. .

Looking at the overall operation through the configuration as described above are as follows.

First, an area of the message queue 100 to be used in communication is created through message queue creation. At this time, the send task 200 obtains an empty message queue pointer 110 address using a queue get.

Then, the contents of the data to be transmitted are written directly to the pointer area 210, and after the data is ready to be transmitted, data is transmitted using a send process.

Meanwhile, the task 300 to receive a message receives data through a receive process.

However, as in the conventional method shown in FIG. 1 of the accompanying drawings, direct reception is used without having to make a local area (buffer 31 of FIG. 1 of the accompanying drawings).

At this time, the result returned is the message queue pointer 110 address and the data size actually received.

Next, the receive task 300 uses the received data through a read process and then uses queue free when no longer needed, so that the message queue pointer area 110 may be no longer used. Notify this need and free this area for reuse.

Here, the message queue generation, transmission, and reception process according to the present invention as described above will be described in more detail.

Looking at the overall operation through the configuration as described above are as follows.

3 is a flowchart illustrating a message queue creation process in a message queue communication process according to the present invention.

As shown therein, when the required message size and number are input (ST101), calculating a required memory size (ST102), and after calculating the memory size, checking whether a memory exists (ST103). And, if the check result memory does not exist, outputs an error value and returns it, and if the check result memory exists, allocating memory (ST105), and after the memory allocation, a semaphore (Semaphore, multitask) Generating a variable used for synchronization or exclusive control between tasks in the OS (ST106), checking whether the semaphore is generated normally (ST107), and outputting an error value if the semaphore is not generated as a result. When the semaphore is generated, the process returns to the step of terminating the message queue creation process.

4 is a flowchart illustrating a message queue send process in the message queue communication process according to the present invention.

As shown in the drawing, the state of the message queue is checked (ST201) to check whether the queue is empty (ST202), and if the check result is not empty, the error value is output and returned (ST203). Assigning a queue when the check result queue is empty (ST204), returning a pointer of the allocated queue after assigning the queue (ST205), and writing the transmitted data after the return (ST205). a step of writing (ST206), a step of checking whether there is a task to receive after the data is written (ST207), and a message send number count if the check result does not exist ) Increase the step ST208, give the semaphore if the check result reception task exists (ST209), and decrease the message receive number count after the semaphore give ( S T210) and then terminating the message queue transmission process.

5 is a flowchart illustrating a message queue receiving process in a message queue communication process according to the present invention.

As shown therein, the state of the message queue is checked (ST301) to check whether the queue is empty (ST302), and if the check result queue is empty, the semaphore is taken (ST303), and the check result Decrementing the message send number count when the queue is not empty (ST304), returning a pointer of the received queue after the decrement (ST305), and transmitting the data after the return Reading (ST306), releasing the resources of the allocated queue (ST307) and ending the message queue receiving process.

As described above, in the detailed description of the present invention, specific embodiments of the message queue communication method in the real-time operating system will be described. However, the present invention may be modified in various ways without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

According to the present invention "message queue communication method in a real-time operating system" described above,

By receiving a pointer to an empty queue before the Message Queue Send process, it allows the data to be sent to be written directly to the Message Queue, and also a pointer to the queue that was received during Message Queue Receive. By avoiding the memory copying process at all, the load that takes up the most of the CPU's execution time can be reduced, and the same performance can be guaranteed at all times regardless of the amount of data in terms of the transfer rate that is reduced by the amount of data. Has the advantage.

In addition, the present invention has the advantage that the performance improvement effect can be expected in a system that frequently uses the message queue, such as a mobile communication system by omitting the memory copy process in the communication method process through the message queue.

Claims (4)

In a message queue communication method in a real time operating system, Creating a message queue area to be used in communication through Message Queue Create; After the message queue is created, acquiring an empty message queue pointer address using a queue get in a send task; After the address is obtained, writing the contents of the data to be transmitted directly to the pointer area, and transmitting data using a send process when the data is ready to be transmitted; When the data is transmitted, receiving data directly through a receiving process in a task to receive a message; Using the received data in a receive task through a read process; After using the data, if it is not necessary, using a queue free (queue free) using the message queue pointer area is not necessary, and the real-time operating system comprising the step of freeing for reuse of the area To communicate with Message Queuing in Windows. The method of claim 1, wherein the process of creating a message queue comprises: Calculating a required memory size if a required message size and number are input; After calculating the memory size, checking whether a memory exists; Outputting an error value if the memory does not exist and returning the result, and allocating the memory if the memory exists; Generating a semaphore after the memory allocation, and checking whether the semaphore is normally generated; And outputting an error value when the semaphore is not generated, and ending the message queue generation process when the semaphore is generated. The method of claim 1, wherein the message queue send process comprises: Checking the status of the message queue to check if the queue is empty; Outputting and returning an error value if the queue is not empty and assigning a queue if the queue is empty; After assigning the queue, returning a pointer of the allocated queue, and then writing the transmitted data; After writing the data, checking whether there is a task to receive; Increasing a Message Send Number Count when there is no receiving task as a result of the checking; Giving a semaphore if there is a receiving task as a result of the checking; And after the semaphore gib, reducing the message reception number count and terminating the message queue transmission process. The method of claim 1, wherein the message queue receiving process comprises: Checking the status of the message queue to check if the queue is empty; Taking a semaphore when the check result queue is empty, and decreasing a message send number count when the check result queue is not empty; After the reduction, returning a pointer of the received queue, and then reading the transmitted data; Message queue communication method in a real-time operating system comprising the step of releasing the message queue receiving process after releasing the allocated resources of the queue.