CN103488536B - Method for scheduling task, device and operating system - Google Patents

Abstract

Embodiments of the present invention provide a task scheduling method, device, and operating system. The method of the present invention includes: registering and generating a task scheduling index list according to all subtasks included in the task; Subtasks: according to the subtasks that need to be scheduled for execution when the user program schedules the task, update the task scheduling index list so that the task scheduling index list only includes the subtasks that need to be scheduled for execution when the user program schedules the task Subtasks: scheduling and executing each subtask in the updated task scheduling index list to complete the task scheduled by the user program. In the embodiment of the present invention, by determining the subtasks that need to be scheduled and executed by the user program scheduling task and updating the task scheduling index list, dynamic scheduling of tasks is realized, and subtasks that do not need to be executed are no longer scheduled and executed, so as to reduce useless overhead, reduce CPU load and system power consumption purposes.

Description

Task scheduling method, device and operating system

technical field

The embodiment of the present invention relates to computer operating system technology, and in particular to a task scheduling method, device and operating system.

Background technique

In the field of electronic equipment, power consumption is a very important indicator, and the CPU load of the processor will directly affect the power consumption of the entire system. For a product, in order to enhance competitiveness, some restrictions will be imposed on hardware resources, such as CPU frequency, bus frequency, double-rate synchronous dynamic random access memory DDR frequency, etc. Therefore, how to reduce key CPU indicators in limited CPU resources, such as Average load and peak load are important technical means to reduce product power consumption.

In the prior art, CPU processing tasks are scheduled serially, that is, after the task program is compiled, the sequence of task scheduling execution is static and fixed. For example, FIG. 1 is a schematic diagram of task scheduling sequence in the prior art. As shown in FIG. 1 , an interrupt processing task includes multiple subtasks FUN_1, FUN_2, FUN_3, FUN_4...FUN_X, when the interrupt processing task is called, then All subtasks need to be executed sequentially.

When a user program calls a certain task, not all subtasks need to be called, such as the subtasks FUN_1, FUN_3 and FUN_4 in FIG. 1 . However, because the existing task scheduling is executed in a static order, even if there are subtasks that do not need to be executed, operations such as stack pushing, unstacking, and conditional judgment need to be scheduled in the process of scheduling tasks, resulting in useless scheduling. overhead, increasing CPU load and system power consumption.

Contents of the invention

Embodiments of the present invention provide a task scheduling method, device, and operating system to achieve the purpose of bypassing subtasks in the task that do not need to be scheduled for execution when a user program calls a certain task, thereby reducing CPU load and system power consumption.

In a first aspect, an embodiment of the present invention provides a task scheduling method, including:

According to all subtasks included in the task, register and generate a task scheduling index list, the task scheduling index list at least includes the index of each subtask and the function entry address pointer corresponding to each subtask;

Determine the subtasks that need to be scheduled for execution when the user program schedules the task;

According to the subtasks that need to be scheduled for execution when the user program schedules the task, update the task scheduling index list so that the task scheduling index list only includes the subtasks that need to be scheduled for execution when the user program schedules the task;

Scheduling and executing each subtask in the updated task scheduling index list to complete the scheduling of the task by the user program.

In a first possible implementation manner of the first aspect, the scheduling executes each subtask in the updated task scheduling index list to complete the user program scheduling the task, including:

According to the index of each subtask in the task scheduling index list after the update, jump to the function entry pointer address corresponding to each subtask in sequence from the first subtask to execute each subtask code program, if the executed function entry If the pointer address is empty, exit the task scheduling.

With reference to the first aspect or the first possible implementation of the first aspect, in the second possible implementation of the first aspect, the registration and generation of the task scheduling index list according to all subtasks included in the task includes:

According to the execution order of each subtask included in the task, generate the index number of each subtask in the task scheduling index list, so that the execution order of each subtask is consistent with the order of the index number of each subtask;

A task scheduling index list is generated according to the sequence registration of the index numbers of the subtasks.

With reference to the second possible implementation of the first aspect, in the third possible implementation of the first aspect, the subtasks that need to be scheduled for execution when scheduling the task according to the user program are updated to update the task scheduling index list so that the task scheduling index list only includes subtasks that need to be scheduled for execution when the user program schedules the task, including:

If there are subtasks in the task scheduling index list that do not need to be scheduled for execution when the user program schedules the task, then delete the subtasks from the task scheduling index list, and perform all remaining subtasks based on The index numbers of the subtasks are reordered; or,

If there is no subtask that needs to be scheduled for execution when the user program schedules the task in the task scheduling index list, add the subtask registration to the task scheduling index list, and base all subtasks on the basis of The index numbers of each subtask are reordered.

In combination with the first aspect and the first to third possible implementations of the first aspect, in the fourth possible implementation of the first aspect, the index of each subtask is the corresponding function of each subtask Entry address.

With reference to the first aspect and the first to fourth possible implementation manners of the first aspect, in a fifth possible implementation manner of the first aspect, the task is a task executed periodically in the system.

In a second aspect, an embodiment of the present invention provides a task scheduling device, including:

The registration generation module is used to register and generate a task scheduling index list according to all subtasks included in the task, and the task scheduling index list includes at least the index of each subtask and the function entry address pointer corresponding to each subtask;

A determining subtask module, configured to determine the subtasks that need to be scheduled for execution when the user program schedules the task;

An update task scheduling index list module, configured to schedule subtasks that need to be executed when scheduling the task according to the user program, and update the task scheduling index list so that the task scheduling index list only includes the subtasks scheduled by the user program. Subtasks that need to be scheduled for execution during the task;

The scheduling execution module is configured to schedule and execute each subtask in the updated task scheduling index list to complete the task scheduled by the user program.

In the first possible implementation manner of the second aspect, the scheduling execution module is specifically configured to:

According to the index of each subtask in the task scheduling index list after the update, jump to the function entry pointer address corresponding to each subtask in sequence from the first subtask to execute each subtask code program, if the executed function entry If the pointer address is empty, exit the task scheduling.

With reference to the second aspect or the first possible implementation manner of the second aspect, in the second possible implementation manner of the second aspect, the registration generation module includes:

An index generation unit, configured to generate the index number of each subtask in the task scheduling index list according to the execution order of each subtask included in the task, so that the execution order of each subtask is consistent with the index number of each subtask The order of numbers remains the same;

A task scheduling index list generation unit is configured to register and generate a task scheduling index list according to the order of the index numbers of the subtasks.

With reference to the second possible implementation of the second aspect, in the third possible implementation of the second aspect, the module for updating the task scheduling index list is specifically used for:

If there are subtasks in the task scheduling index list that do not need to be scheduled for execution when the user program schedules the task, then delete the subtasks from the task scheduling index list, and perform all remaining subtasks based on The index numbers of the subtasks are reordered; or,

If there is no subtask that needs to be scheduled for execution when the user program schedules the task in the task scheduling index list, add the subtask registration to the task scheduling index list, and base all subtasks on the basis of The index numbers of each subtask are reordered.

In combination with the second aspect and the first to third possible implementations of the second aspect, in the fourth possible implementation of the second aspect, the index of each subtask is the corresponding function of each subtask Entry address.

With reference to the second aspect and the first to fourth possible implementation manners of the second aspect, in a fifth possible implementation manner of the second aspect, the task is a task periodically executed in the system.

In a third aspect, an embodiment of the present invention provides an operating system, including the second aspect, and a task scheduling device in any possible implementation manners from the first to the fifth aspects of the second aspect.

The embodiment of the present invention realizes task dynamic scheduling by determining the subtasks that need to be scheduled and executed by the user program scheduling task and updating the task scheduling index list. consumption purpose.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic diagram of a task scheduling sequence in the prior art;

FIG. 2 is a flow chart of Embodiment 1 of a task scheduling method of the present invention;

FIG. 3 is a schematic diagram of a task scheduling index list generated by registration in FIG. 2;

FIG. 4 is a schematic diagram of an updated task scheduling index list in FIG. 2;

FIG. 5 is a flowchart of Embodiment 2 of a task scheduling method of the present invention;

FIG. 6 is a structural diagram of Embodiment 1 of a task scheduling device according to the present invention;

7 is a structural diagram of Embodiment 2 of a task scheduling device according to the present invention;

FIG. 8 is a structure diagram of Embodiment 1 of an operating system of the present invention;

FIG. 9 is a software scheduling architecture diagram of FIG. 8 .

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Example 1

FIG. 2 is a flow chart of Embodiment 1 of a task scheduling method of the present invention. The execution subject of this method is a task scheduling device, which can be placed in an operating system, such as Linux, Windows, Solaris, and VxWorks. As shown in Figure 2, the method specifically includes:

Step 201, register and generate a task scheduling index list according to all subtasks included in the task, and the task scheduling index list includes at least the index of each subtask and the function entry address pointer corresponding to each subtask;

In this step, the subtask is a subfunction in the task function. The task scheduling index table is stored in the memory, and the space can be uniformly applied for and maintained during implementation, or can be maintained by each specific business module.

Figure 3 is a schematic diagram of the task scheduling index list generated by registration in Figure 2. As shown in Figure 3, if the task includes multiple subtasks FUN_1, FUN_2, FUN_3, FUN_4...FUN_X, the task scheduling index list generated by registration includes Take the index of the above subtask (such as 1, 2, 3...X) and the corresponding function entry address pointer (such as FunPtr_1, FunPtr_2, FunPtr_3, FunPtr_4...FunPtr_X).

Step 202, determining the subtasks that need to be scheduled for execution when the user program schedules the task;

For example, when it is determined that a certain user program calls the task in Figure 3, it only needs to call the two subtasks FUN_1 and FUN_X.

Step 203: According to the subtasks that need to be scheduled for execution when the user program schedules the task, update the task scheduling index list so that the task scheduling index list only includes the subtasks that need to be scheduled for execution when the user program schedules the task Subtasks;

In this step, on the basis of registering the generated task scheduling index list, the task scheduling index list is updated based on the subtasks determined in step 202 that need to be scheduled for execution when the user program schedules the task. For example, Figure 4 is a schematic diagram of the updated task scheduling index list in Figure 2. As shown in Figure 4, when a user program calls a task, only two subtasks, FUN_1 and FUN_X, need to be called, so the generated task scheduling index list will be registered To update, only keep the relevant information of the two subtasks FUN_1 and FUN_X.

Step 204, schedule and execute each subtask in the updated task scheduling index list to complete the task scheduled by the user program.

Compared with the prior art, when a user program schedules a certain task, all subtasks of the task need to be scheduled. The embodiment of the present invention directly The required subtasks are executed in the order of the updated task scheduling index list, and the required subtasks can be directly executed without query. In this way, dynamic scheduling of tasks is realized, and subtasks that do not need to be executed are not scheduled for execution, so as to achieve the purpose of reducing the overhead caused by useless scheduling, reducing CPU load and system power consumption.

Preferably, on the basis of the above embodiments, the task is a task executed periodically in the system. For each periodic task, there will be an independent task entry (such as interrupt entry function, message processing function, etc.). Taking the WCDMA system as an example, there are generally modules such as the protocol layer, the physical layer, and the underlying air interface. For the physical layer module, periodic tasks need to be processed frequently: tasks such as 2ms subframe tasks, measurement, search, and decoding.

Periodically executed tasks need to be called frequently and occupy the largest system resources. If the technical solution of this embodiment is adopted, the CPU load and system power consumption will be effectively reduced. Therefore, the more frequent tasks are called, the technical solution of this embodiment The greater the technical effect will be.

Example 2

Fig. 5 is a flow chart of Embodiment 2 of a task scheduling method of the present invention, as shown in Fig. 5 , specifically including:

Step 501, according to the execution order of each subtask included in the task, generate the index number of each subtask in the task scheduling index list, so that the execution order of each subtask and the order of the index number of each subtask are maintained consistent;

Generate the index number of each subtask in the task scheduling index list according to the execution order of each subtask included in the task, so as to ensure that the execution order is consistent with the relative order of the tasks when statically compiled, so there will be no problem during execution Because the order is inconsistent, the consistency of the software logic is broken.

Step 502: Register and generate a task scheduling index list according to the index numbers of the subtasks in sequence, and the task scheduling index list includes at least the index of each subtask and the function entry address pointer corresponding to each subtask;

Step 503, determining the subtasks that need to be scheduled for execution when the user program schedules the task;

Step 504: If there are subtasks in the task scheduling index list that do not need to be scheduled for execution when the user program schedules the task, delete the subtasks from the task scheduling index list, and Subtasks are reordered based on the index number of each subtask;

Taking the 2ms subframe task in the wideband code division multiple access (wideband CDMA, WCDMA for short) system as an example, the following deletion function can be set:

void DEMO_Del_Wcdma2msTask(int SubFrameIndex, void *pFun);

Function description: delete 2ms periodic tasks

Parameter description: int SubFrameIndex-----subframe index: 0~4

void*pFun-----task entry (function pointer)

Implementation details: 1. Find the "task scheduling index table" corresponding to the 2ms subframe;

2. Delete the subtask and delete the function pointer from the "task scheduling index table";

3. Subsequent tasks are advanced one by one, and NULL (null pointer) is processed at the end.

Optionally, in this step, if there is no subtask that needs to be scheduled for execution when the user program schedules the task in the task scheduling index list, add the subtask registration to the task scheduling index list , and reorder all the subtasks based on the index number of each subtask. Taking the 2ms subframe task in the WCDMA system as an example, the following addition function can be set:

void DEMO_Add_Wcdma2msTask(int SubFrameIndex, void *pFun);

Function description: Add 2ms periodic tasks

Parameter description: int SubFrameIndex-----subframe index: 0~4

void*pFun-----task entry (function pointer)

Implementation details: 1. Find the "task scheduling index table" corresponding to the 2ms subframe;

2. Add subtasks and add function pointers to the "task scheduling index table";

3. Sort the tasks according to the static compilation order.

Preferably, the index of each subtask can also directly use the corresponding function entry address of each subtask, because after the software is compiled, each function entry has a unique entry pointer, and each task entry pointer will not Repetition not only satisfies the sorting requirement, but also satisfies the requirement of using the function entry pointer as an index.

Step 505, according to the index of each subtask in the updated task scheduling index list, jump sequentially from the first subtask to the function entry pointer address corresponding to each subtask to execute each subtask code program;

Step 506, the executed function entry pointer address is empty;

Determine whether the function entry pointer address corresponding to each subtask executed in sequence is empty, if it is empty, it means that the subtask called when the user program is executed has been executed, and step 507 is executed; if the address is not empty, then step 505 is continued .

Step 507, exit the task scheduling.

In this embodiment, by determining the sub-functions that need to be scheduled for execution when the user program is called, and by adding and deleting sub-tasks in the task scheduling index list, dynamic scheduling of tasks is realized, and tasks can be added and deleted. And there is no need to call useless subtask overhead, reduce CPU load, reduce the demand for product hardware, and also reduce system power consumption.

Example 3

FIG. 6 is a structural diagram of Embodiment 1 of a task scheduling device according to the present invention. As shown in FIG. 6, the device 60 includes:

The registration generation module 61 is configured to register and generate a task scheduling index list according to all subtasks included in the task, and the task scheduling index list includes at least the index of each subtask and the function entry address pointer corresponding to each subtask;

Determine the subtask module 62, configured to determine the subtasks that need to be scheduled for execution when the user program schedules the task;

The update task scheduling index list module 63 is configured to update the task scheduling index list so that the task scheduling index list only includes the subtasks scheduled for execution by the user program when scheduling the task. Subtasks that need to be scheduled for execution when describing tasks;

The scheduling execution module 64 is configured to schedule and execute each subtask in the updated task scheduling index list to complete the task scheduled by the user program.

The device of this embodiment is used to implement the technical solution of the method embodiment shown in FIG. 2 , and its implementation principle and technical effect are similar, and details are not repeated here.

Example 4

FIG. 7 is a structural diagram of Embodiment 2 of a task scheduling device according to the present invention. As shown in FIG. 7 , the device 70 is based on the previous embodiment, and further, the scheduling execution module 64 is specifically used for:

According to the index of each subtask in the task scheduling index list after the update, jump to the function entry pointer address corresponding to each subtask in sequence from the first subtask to execute each subtask code program, if the executed function entry If the pointer address is empty, exit the task scheduling.

The registration generating module 61 includes:

The generating index unit 71 is used to generate the index number of each subtask in the task scheduling index list according to the execution order of each subtask included in the task, so that the execution order of each subtask is consistent with the execution order of each subtask The order of index numbers remains the same;

The generating task scheduling index list unit 72 is configured to register and generate the task scheduling index list according to the order of the index numbers of the subtasks.

Specifically, the update task scheduling index list module 63 is specifically used for:

If there are subtasks in the task scheduling index list that do not need to be scheduled for execution when the user program schedules the task, then delete the subtasks from the task scheduling index list, and perform all remaining subtasks based on The index numbers of the subtasks are reordered; or,

If there is no subtask that needs to be scheduled for execution when the user program schedules the task in the task scheduling index list, add the subtask registration to the task scheduling index list, and base all subtasks on the basis of The index numbers of each subtask are reordered.

Further, the index of each subtask is the corresponding function entry address of each subtask.

Preferably, the task is a task executed periodically in the system.

The device of this embodiment is used to implement the technical solution of the method embodiment shown in FIG. 5 , and its implementation principles and technical effects are similar, and details are not repeated here.

Example 5

FIG. 8 is a structure diagram of Embodiment 1 of an operating system according to the present invention. As shown in FIG. 8 , the operating system includes a task scheduling device 80 .

In this embodiment, the operating system may be Linux, Windows, Solaris, VxWorks and the like.

The task scheduling device 80 in this embodiment can adopt the structure of the task scheduling device shown in any one of the embodiments in FIG. 6 or 7 , and can correspondingly execute the method described in any one of the embodiments in FIG. 2 or 5 .

Figure 9 is a software scheduling architecture diagram of Figure 8, as shown in Figure 9, the specific explanation is as follows:

CPU core: the main body of software instruction execution;

Double Rate Synchronous Dynamic Random Access Memory (Double Data Rate, referred to as DDR): software code storage medium; similar storage media can be extended to Synchronous Dynamic Random Access Memory (Synchronous Dynamic Random Access Memory, referred to as SDRAM), read-only memory (Read- Only Memory, referred to as ROM), etc.;

Advanced High Performance Bus (AHB for short)/Advanced eXtensible Interface (AXI for short) BUS: system bus, used to link various modules to maintain synchronization and complete data interaction;

Other modules: other modules required for system operation;

push: The system pushes the stack to save the system context;

pop: The system unstacks and restores the system context;

When the CPU is running, it needs to obtain instructions (such as push, pop, etc.) from the DDR through the AHB/AXI BUS; the number of instructions determines the length of CPU execution time; in the embodiment of the present invention, the CPU does not need to completely run all subtasks in the DDR , you only need to run the subtasks that need to be scheduled for execution (such as task0, task1, task2, and task3 in Figure 9), and you can exit halfway after executing the required subtasks, reducing the useless overhead of the CPU.

The operating system of the above embodiment can be used in various application scenarios, especially involving many periodically executed tasks, such as taking the global system for mobile communications (global system for mobile communications, GSM for short) system as an example, generally there will be a protocol layer, Physical layer, bottom air interface and other modules. For the physical layer module, periodic tasks need to be processed frequently: tasks such as time slot tasks, measurement, demodulation, and decoding. The tasks listed above are all periodically repeatable; take the decoding task as an example; in different business states, such as CS state (voice), PS state (data transmission) and PCH state (idle solution paging); translation The code processing flow is not exactly the same, and the tasks that need to be scheduled are also different. For example, in the PCH state, there are few tasks to be processed, only TASK_COM, TASK_A1 and TASK_A2; while in the PS state, there are many tasks to be processed, including TASK_COM, TASK_B1, TASK_B2...TASK_A266. When switching from the PCH state to the PS state, it is necessary to update the "task scheduling index list", mount the tasks that need to be executed in the PS state, and delete the tasks that are executed only in the PCH state; for the public task TASK_COM, it needs to be retained.

Since the operating system in the embodiment of the present invention does not need to execute useless subtasks, the more system scenarios that periodically execute tasks exist, the greater the technical effect brought by the operating system in the embodiment of the present invention.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (7)

1. A kind of 1. method for scheduling task, it is characterised in that including：

   All subtasks included according to task, registration generation task scheduling index list, the task scheduling index list Function entrance address pointer corresponding to index and each subtask including at least each subtask；

   Determine to need to dispatch the subtask performed during task described in user procedure dispatching；

   According to the subtask for needing scheduling to perform described in the user procedure dispatching during task, the task scheduling index column is updated Table is so that the task scheduling index list needs to dispatch the son times performed when only including task described in the user procedure dispatching Business；

   Scheduling performs each subtask in the task scheduling index list after renewal to complete to appoint described in the user procedure dispatching Business；

   All subtasks included according to task, registration generation task scheduling index list, including：

   The execution sequence of each subtask included according to the task, each son generated in the task scheduling index list are appointed The call number of business, so that the execution sequence of each subtask and the call number order of each subtask are consistent；

   Call number sequential registration according to each subtask generates task scheduling index list；

   The scheduling performs each subtask in the task scheduling index list after renewal to complete the user procedure dispatching institute Task is stated, including：

   The index of each subtask in the task scheduling index list after renewal order since first subtask Jump to and perform each subtask program in machine code corresponding to each subtask at function entrance pointer address, if the function entrance performed refers to Pin address is sky, then exits the task scheduling；

   It is described to need to dispatch the subtask performed during task according to the user procedure dispatching, update the task scheduling rope Draw list so that needs scheduling execution when the task scheduling index list only includes task described in the user procedure dispatching Subtask, including：

   If the son of execution need not be dispatched when task described in the user procedure dispatching be present in the task scheduling index list Task, then the subtask is deleted from the task scheduling index list, and each son is based on to remaining whole subtask The call number of task carries out order again and sorted；Or,

   If be not present in the task scheduling index list described in the user procedure dispatching needs to dispatch the son performed during task Task, then subtask registration is increased in the task scheduling index list, and each son is based on to the subtask of whole The call number of task carries out order again and sorted.
2. 2. according to the method for claim 1, it is characterised in that the index of each subtask is pair of each subtask The function entrance address answered.
3. 3. according to any described methods of claim 1-2, it is characterised in that the task is times periodically performed in system Business.
4. A kind of 4. task scheduling apparatus, it is characterised in that including：

   Generation module is registered, it is described for all subtasks included according to task, registration generation task scheduling index list Task scheduling index list is including at least function entrance address pointer corresponding to the index of each subtask and each subtask；

   Subtask module being determined, needing during for determining task described in user procedure dispatching to dispatch the subtask performed；

   Task scheduling index list module is updated, for needing to dispatch what is performed during task according to the user procedure dispatching Subtask, the task scheduling index list is updated so that the task scheduling index list only includes the user procedure dispatching Need to dispatch the subtask performed during the task；

   Execution module is dispatched, each subtask in the task scheduling index list after updating is performed to complete the use for dispatching Task described in the program scheduler of family；

   The registration generation module, including：

   Indexing units are generated, for the execution sequence of each subtask included according to the task, generate the task scheduling The call number of each subtask in index list, so that the execution sequence of each subtask and the call number order of each subtask are kept Unanimously；

   Task scheduling index list unit is generated, task scheduling is generated for the call number sequential registration according to each subtask Index list；

   The scheduling execution module, is specifically used for：

   The index of each subtask in the task scheduling index list after renewal order since first subtask Jump to and perform each subtask program in machine code corresponding to each subtask at function entrance pointer address, if the function entrance performed refers to Pin address is sky, then exits the task scheduling；

   The renewal task scheduling index list module, is specifically used for：

   If the son of execution need not be dispatched when task described in the user procedure dispatching be present in the task scheduling index list Task, then the subtask is deleted from the task scheduling index list, and each son is based on to remaining whole subtask The call number of task carries out order again and sorted；Or,

   If be not present in the task scheduling index list described in the user procedure dispatching needs to dispatch the son performed during task Task, then subtask registration is increased in the task scheduling index list, and each son is based on to the subtask of whole The call number of task carries out order again and sorted.
5. 5. device according to claim 4, it is characterised in that the index of each subtask is pair of each subtask The function entrance address answered.
6. 6. according to any described devices of claim 4-5, it is characterised in that the task is times periodically performed in system Business.
7. 7. a kind of operating system, it is characterised in that including a kind of any described task scheduling apparatus of claim 4-6.