JPH06224970A - Communication speed adaptive variable device - Google Patents

Abstract

PURPOSE:To improve the communication efficiency of a real time system by utilizing effectively an idle time of system processing. CONSTITUTION:The device is provided with a means (#1) measuring a CPU occupying time required for internal processing, a means (#2) discriminating whether or not the internal processing is a load based on the measurement result, means (#4, #7) revising the communication speed based on the result of discrimination, and means (#3, #6) informing a communication object of the revised communication speed. When the real time system does not so much time for the internal processing, the communication speed to the communication object is increased, and when much time is required for the internal processing, the communication speed to the communication object is decreased to attain efficient communication.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication speed adaptive variable device, and is used for a real-time system having a function of communicating with a system to be communicated.

[0002]

2. Description of the Related Art Conventionally, a real-time system including a communication means and a screen control means has been widely used as a control target of a CPU. In the case of a real-time system, it is necessary to respond to the request for communication in real time. Also, since it is necessary to respond to other requests such as screen control in real time, when the processing capacity of the CPU exceeds the limit due to frequent communication,
Delays such as screen control and missed communications occur. Therefore, the communication speed is kept constant so as not to burden the CPU.

[0003]

As described above, because of the limitation of the communication speed, in the current real time system, no matter how the internal processing of the system is,
Communicating at the same communication speed. Therefore, if it is possible to realize a communication speed adaptive variable device that increases the communication speed when the system does not spend much time in the internal processing and decreases the communication speed when spending a lot of time in the internal processing, it would be efficient. It should be possible to communicate.

The present invention has been made in view of the above circumstances, and an object thereof is to improve the communication efficiency of a real-time system by effectively utilizing the idle time of the processing of the system. It is to provide a communication speed adaptive variable device capable of performing the above.

[0005]

In order to solve the above-mentioned problems, the communication speed adaptive variable apparatus of the present invention has the configuration shown in FIG.
In the real-time system 2 having the function of communicating with the communication target 1, as shown in FIG. 1, means (# 1) for measuring the CPU monopolization time required for internal processing,
A means (# 2) for judging whether or not the internal processing is burdened from the measurement result, a means (# 4, # 7) for changing the communication speed according to the judgment result, and a communication target 1 And a means (# 3, # 6) for notifying the changed communication speed.

[0006]

The operation of the present invention will be described with reference to the flowchart of FIG. In the process of # 1, by measuring the CPU monopolization time required for the internal processing in the real-time system, the degree to which the internal processing is burdened is checked. next,
In the process of # 2, it is determined whether or not the internal processing is burdened by the means for determining whether or not the internal processing is burdened from the measurement result of the CPU exclusive time.
If the internal processing is burdensome, the burden on the CPU is reduced by lowering the communication speed in the processing of # 4. In addition, prior to that, the communication target is notified that the communication speed will be reduced in the process of # 3. Also,#
If it is determined that the internal processing does not become a burden in the processing of No. 2, it is determined whether or not the CPU idle time is large in the processing of # 5. The process shifts to the process of 8 and the communication speed is not changed.
However, if it is determined in the process of # 5 that the CPU idle time is large, efficient communication can be performed by increasing the communication speed. Therefore, the communication speed is increased in the process of # 7.
In addition, prior to that, the communication target is notified that the communication speed will be increased in the process of # 6. This makes effective use of the free time of the processing of the real-time system,
It is possible to improve communication efficiency.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the operation of a communication speed adaptive variable device of the present invention, and FIG. 2 shows the communication status between a real-time system and a communication target when the communication speed is changed. In this embodiment, as the means for measuring the CPU monopolization time required for internal processing, the task with the lowest priority of the real-time system is used, and the CPU monopolization time is measured by measuring the frequency of control transfer to the task. ing. As a means to determine whether the internal processing is overloaded, two kinds of thresholds, an upper limit and a lower limit, are set for the number of times the control is transferred to the task with the lowest priority using the task with the lowest priority. If the upper limit is exceeded, it is determined that the CPU has a lot of free time, and if the lower limit is exceeded, the CPU is idle.
Judging that the free time is low and internal processing is a burden.

As means for changing the communication speed,
This is achieved by changing the baud rate of the communication LSI. Further, as a means for notifying the communication target of the communication speed to be changed, it is realized by transmitting the communication speed change command to the communication target 1 and waiting for the reply of the confirmation command ACK. ing. That is, as shown in FIG. 2, when the communication speed is to be changed while normal communication is being performed between the real-time system 2 and the communication target 1 at a predetermined communication speed, The communication speed change command is transmitted to 1. In response to this command, the communication target 1 sends back a confirmation command ACK to the real-time system 2, whereby the real-time system 2 can know that the communication target has confirmed the change in the communication speed. After that, normal communication is performed between the real-time system 2 and the communication target 1 at a communication speed different from before.

[0009]

According to the present invention, in a real-time system having a function of communicating with a communication object, the CPU monopolization time required for internal processing is measured, and it is judged from the measurement result whether the internal processing is a burden. The communication speed is changed according to the judgment result, and the changed communication speed is notified to the communication target. Therefore, when the real-time system does not spend much time on internal processing, the communication speed to the communication target is increased. At the same time, when a large amount of time is spent on internal processing, there is an effect that communication can be efficiently performed by reducing the communication speed for the communication target.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining the operation of the present invention.

FIG. 2 is a block diagram showing an embodiment of means for transmitting a communication speed to a communication target.

[Explanation of symbols]

 # 1 CPU exclusive time measurement means # 2 Internal processing load determination means # 3 Communication speed notification means # 4 Communication speed reduction means # 5 CPU idle time determination means # 6 Communication speed notification means # 7 Communication speed increase means

Claims (1)

[Claims] 1. In a real-time system having a function of communicating with a communication target, means for measuring a CPU monopolization time required for internal processing, means for judging whether or not the internal processing is burdened from the measurement result, A communication speed adaptive variable device comprising: means for changing a communication speed according to a result of determination; and means for notifying a communication target of the changed communication speed.