A method for scheduling analysis of embedded real-time systems

Abstract

The application provides a kind of embedded real-time system schedulability analysis method, belong to embedded system schedulability analysis technical field, specifically includes step 1: establish IO model based on AADL;Step 2: establish embedded system model based on time automaton;Step 3: simulate embedded system operation, schedulability analysis is carried out.Through the processing scheme of the application, the accuracy of schedulability analysis result is improved.

Description

Technical Field

[0001] The present application relates to the field of schedulable analysis of embedded systems, and in particular to a schedulable analysis method for embedded real-time systems. Background Art

[0002] Safety- and mission-critical embedded real-time systems, exemplified by aerospace, must ensure both functional execution correctness and timing accuracy. Furthermore, in embedded real-time systems, I / O resources, such as sensor resources, actuator resources, and network resources, are crucial. Existing embedded system scheduling design and analysis methods focus on processors and deployed software tasks, lacking support for I / O resources or abstracting I / O resources into tasks and processors. This results in inaccurate schedulability analysis. Summary of the Invention

[0003] In view of this, the present application provides a schedulable analysis method for an embedded real-time system, which solves the problems in the prior art and improves the accuracy of the schedulable analysis results.

[0004] The present application provides an embedded real-time system schedulability analysis method using the following technical solutions:

[0005] A schedulable analysis method for an embedded real-time system, comprising:

[0006] Step 1: Establish an IO model based on AADL;

[0007] Step 2: Establish an embedded system model based on timed automata;

[0008] Step 3: Simulate the operation of the embedded system and perform schedulability analysis.

[0009] Optionally, the step 1 specifically includes: establishing an IO resource provider model, including data, storage, and IO devices;

[0010] Establish an IO resource subscriber model, including threads and processes;

[0011] Establish a relational model of IO resources, including PCP, I PCP, and PIP protocols, in the IO resource relational model;

[0012] Establish the start and end times for a subscriber's access to a resource.

[0013] Optionally, step 2 specifically includes: establishing a time automaton model for the task, establishing a time automaton model for the operating system scheduling policy, establishing a time automaton model for the IO resource scheduling policy, and establishing a synchronization relationship between the time automaton for the task, the time automaton for the operating system scheduling policy, and the time automaton for the IO resource scheduling policy.

[0014] Optionally, step 3 specifically includes: setting a simulation time according to a periodic attribute of the task set, simulating the execution of all tasks within the simulation time, and comparing whether the actual response time of all tasks is less than the deadline of the task.

[0015] Optionally, in step 1, an embedded real-time system scheduling model is established using the AADL integrated development environment OSATE 2.9.

[0016] Optionally, in step 2, UPPAAL is used to establish a timed automaton model of the embedded real-time system.

[0017] Optionally, in step 3, based on the periodic relationship between tasks, the least common multiple of each task is selected as the simulation period to perform schedulability analysis.

[0018] In summary, this application has the following beneficial technical effects:

[0019] During the embedded system design phase, this application standardizes system design for different types of IO resources. More importantly, it uses simulation methods to verify the correctness of the scheduling design involving IO resources, which can discover system design problems as early as possible and improve the accuracy of schedulable analysis results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 AADL model for resource competition;

[0022] Figure 2 It is the IO resource time automaton model;

[0023] Figure 3 Gantt chart for scheduling. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0026] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0027] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0028] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details.

[0029] An embodiment of the present application provides a schedulable analysis method for an embedded real-time system.

[0030] A schedulable analysis method for an embedded real-time system, comprising:

[0031] Step 1: Establish an IO model based on AADL.

[0032] Step 2: Establish an embedded system model based on timed automata.

[0033] Step 3: Simulate the operation of the embedded system and perform schedulability analysis.

[0034] The step 1 specifically includes: establishing an IO resource provider model, including data, storage and IO devices;

[0035] Establish an IO resource subscriber model, including threads and processes;

[0036] Establish a relational model of IO resources, including PCP, I PCP, and PIP protocols, in the IO resource relational model;

[0037] Establish the start and end times for a subscriber's access to a resource.

[0038] The above step 2 specifically includes: establishing a time automaton model for the task, establishing a time automaton model for the operating system scheduling policy, establishing a time automaton model for the IO resource scheduling policy, and establishing a synchronization relationship among the time automaton for the task, the time automaton for the operating system scheduling policy, and the time automaton for the IO resource scheduling policy.

[0039] The step 3 specifically includes: setting the simulation time according to the periodic attribute of the task set, simulating the execution of all tasks within the simulation time, and comparing whether the actual response time of all tasks is less than the deadline of the task.

[0040] In one embodiment, the schedulability analysis method of an embedded real-time system is specifically described by taking the following model as an example.

[0041] One process contains three threads. The processor adopts the RMS scheduling strategy. The threads are all periodic. The three threads preempt Ethernet resources. The CPU board is connected to the Ethernet card through the PCI bus. The time information of the task is shown in Table 1, where t1 occupies the Ethernet resource time as the second time unit of the execution time, and t3 occupies the Ethernet resource time as the entire execution time.

[0042] Table 1 Task scheduling information

[0043]

[0044]

[0045] In the first step, the embedded real-time system scheduling model was established using the AADL integrated development environment OSATE 2.9, such as Figure 1 As shown, process p1 includes three threads t1, t2, and t3, which are deployed on cpu1. cpu1 communicates with Ethernet card d1 through PCIE bus b1.

[0046] In the second step, we use UPPAAL to build a timed automaton model for the embedded real-time system, such as Figure 2 IO resource time automaton.

[0047] In the third step, based on the period relationship between tasks, we select their least common multiple 24ms as the simulation period and perform schedulability analysis. The results show

[0048] Figure 3 The results of the schedulability analysis are shown. Based on the period relationship between tasks, their least common multiple of 24 is selected as the large period. t1 and t2 are schedulable. t3 only runs for 4 time units before the first deadline and is finally completed in 15ms, exceeding the deadline.

[0049] According to the period relationship between tasks, their least common multiple 24 is selected as the large period. At the 7th ms, t1 occupies the processor and t3 occupies the Ethernet resource. t1 tries to access the Ethernet resource, but cannot access it and is therefore interrupted. t3 occupies the processor and is completed at the 10th ms, meeting the deadline.

[0050] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for analyzing the schedulability of an embedded real-time system, characterized in that: include: Step 1: Establish an IO model based on AADL; Step 2: Establish an embedded system model based on timed automata; Step 3: Simulate the operation of the embedded system and perform schedulability analysis; The step 1 specifically includes: establishing an IO resource provider model, including data, storage and IO devices; Establish an IO resource subscriber model, including threads and processes; Establish a relational model of IO resources, including PCP, IPCP, and PIP protocols, in the IO resource relational model; Establishing the start and end times for subscriber access to resources; The step 2 specifically includes: establishing a time automaton model for the task, establishing a time automaton model for the operating system scheduling policy, establishing a time automaton model for the IO resource scheduling policy, and establishing a synchronization relationship among the time automaton for the task, the time automaton for the operating system scheduling policy, and the time automaton for the IO resource scheduling policy.

2. The method for analyzing the schedulability of embedded real-time systems according to claim 1, wherein: The step 3 specifically includes: setting the simulation time according to the periodic attribute of the task set, simulating the execution of all tasks within the simulation time, and comparing whether the actual response time of all tasks is less than the deadline of the task.

3. The method for analyzing the schedulability of embedded real-time systems according to claim 1, wherein: In the step 1, the AADL integrated development environment OSATE 2.9 is used to establish an embedded real-time system scheduling model.

4. The method for analyzing the schedulability of embedded real-time systems according to claim 1, wherein: In the step 2, UPPAAL is used to establish a timed automaton model of the embedded real-time system.

5. The method for analyzing the schedulability of embedded real-time systems according to claim 2, wherein: In step 3, based on the periodic relationship between tasks, the lowest common multiple of each task is selected as the simulation period to perform schedulability analysis.

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