JP2001092678A - Method for controlling task of multi-media processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling the task of a multi-media processor for realizing the well-balanced execution of each task even when total workloads are increased. SOLUTION: This method comprises a step for calculating the thinning-out rate of each task so that total workloads can be set so as to be made less than total workloads which can be processed by a multi-media processor based on total workloads which can be processed by the multi-media processor, the workloads of each task, and the maximum thinning-out rate of each task when the total workloads at the time of the maximum thinning-out are not beyond the total workloads which can be processed by the multi-medial processor and a step for executing each task in a thinning-out processing mode corresponding to the calculated thinning-out rate of each task.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a task control method for a multimedia processor.

[0002]

2. Description of the Related Art Multimedia processors suitable for image processing and capable of simultaneously processing a plurality of tasks have already been developed. Such a multimedia processor is used for a digital TV, a PC, a TV conference system, and the like.

In a multimedia processor, when a plurality of tasks are processed simultaneously, the total work of these tasks may exceed the total work that can be processed by the processor. Therefore, conventionally, priorities are determined in advance for each task, and when there is a possibility that the total work amount of the tasks may exceed the total work amount that can be processed by the processor, a task with a lower priority order is put into a standby state. I was

[0004] In such a method, when the workload of a certain task is extremely large, there is a possibility that while the task is being executed, another task always stops.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a task control method for a multimedia processor that enables each task to be executed in a well-balanced manner even when the total amount of work increases. .

[0006]

A task control method for a multimedia processor according to the present invention is a task control method for a multimedia processor capable of simultaneously executing a plurality of tasks. A step of calculating a total amount of work when no thinning is performed based on the amount of work of each task to be attempted; the total amount of work when no thinning is performed exceeds the total amount of work that can be processed by the multimedia processor In the case, the step of calculating the total work amount at the time of maximum thinning based on the work amount of each task and the maximum thinning rate of each task, the total work amount at the maximum thinning time is the total work amount that the multimedia processor can process. If not, the total amount of work that the multimedia processor can handle, the amount of work for each task, and Calculating the thinning rate of each task based on the maximum thinning rate of the tasks so that the total work is equal to or less than the total work that the multimedia processor can process, and according to the calculated thinning rate of each task. And a step of executing each task in the thinning processing mode.

Determining the priority for each task, and if the total work at the maximum thinning exceeds the total work that can be processed by the multimedia processor,
It is preferable to provide a step of placing the tasks in a waiting state in order from the one with the lowest priority.

[0008]

Embodiments of the present invention will be described below with reference to FIG.

FIG. 1 shows the configuration of a multimedia processor.

The multimedia processor 100 has a CP
U10, first to third input ports 11, 12, 13, first to third input interfaces (I / F) 21 to 23,
First to third output interfaces (I / F) 31 to 3
3, a first to third output ports 41 to 43, a ROM connection terminal 51, and a RAM connection terminal 52.

First to third input ports 11, 12, 13
Are the first to third input interfaces (I / F) 21 to
23 is connected to the CPU 10. First to third
Output ports 41 to 43 are connected to the CPU 10 via first to third output interfaces (I / Fs) 31 to 33.

A ROM 61 is connected to the ROM connection terminal 51, and a RAM 62 is connected to the RAM connection terminal 52.

In this example, the multimedia processor performs three tasks: audio signal decoding (task name; audio decoding), video signal decoding (task name; video decoding), and communication processing (task name; Modem processing) at the same time.

Table 1 shows task numbers 1 to 3 for each task.
Task name, workload W when no thinning is performed
_n (n is a task number), a maximum thinning rate _An and a priority _Pn . In this specification, the work amount and the total work amount mean the work amount per unit time and the total work amount per unit time.

[0015]

[Table 1]

The maximum thinning rate refers to a maximum reduction rate when the work amount of a task is reduced to a maximum by simplifying the processing content and reducing the processing speed when processing a certain task.

In the case of video decoding, skipping the field to be decoded every few fields reduces the workload of the task. In the case of communication processing, the work load of the task can be reduced by reducing the bit rate.

In this example, the audio decoding
Maximum thinning rate A₁0%, maximum for video decoding
Thinning rate A_TwoIs 20%, maximum thinning for modem processing
Rate A _ThreeIs 70%.

The concept of the task control method performed in this embodiment will be described.

For example, assume that the total work WP that can be processed by the processor is 100. Audio decoding and video decoding has been performed, the modem processing is not performed, workload W ₁ of the audio decoding 5, workload W ₂ video decoding 60, at work amount W ₃ are 0 modem processing In some cases, the total work WA _min is 65. Therefore, in this case, audio decoding and video decoding can be executed at the thinning rate of 0.

Audio decoding, video decoding and modem processing are performed. The work amount W _{1 of} audio decoding is 10, the work amount W _{2 of} video decoding is 80,
When workload W ₃ of modem processing is 50, the total amount of work WA _min is beyond 140, and the processor can process the total amount of work WP a (= 100).

In such a case, since each task cannot be executed as it is, the thinning rate B _n (n is a task number) of each task is set so that the total work is equal to or less than the total work that can be processed by the multimedia processor. ). Specifically, the thinning rate _Bn of each task is obtained based on Expressions 1 and 2. In Expression 1, x is an unknown number indicating what percentage of the maximum thinning rate is to be thinned.

[0023]

(Equation 1)

[0024]

(Equation 2)

According to Equation 1, B ₁ = 0 [%] and B ₂ = 2
0x (%), and B ₃ = 70x [%]. Then, by substituting these into Equation 2, x = 0.78 is obtained. Therefore, B ₁ = 0 [%], B ₂ = 16 [%],
B ₃ = 55 [%]. Work amount W ₁ ′ of each task after thinning out (= W ₁ × (100−B ₁ ) / 100), W ₂ ′
(= W ₂ × (100−B ₂ ) / 100), W ₃ ′ (= W
₃ × (100−B ₃ ) / 100) are 10, 6 respectively.
7, 23, and their sum is 100.

If the total work load WP (= 100) that can be processed by the processor is exceeded even if each task is thinned according to the maximum thinning rate, the tasks are sorted in the order of lower priority. Stop.

FIG. 2 shows a task control processing procedure.

First, the total work W that can be processed by the processor W
Measure P (step 1).

Next, the work amount W of each task_nWhen you measure
In both cases, the maximum thinning rate A of each task _nAnd priority P
_nIs determined (step 2). Maximum thinning rate for each task
A_nAnd priority P_nMay be predetermined or outside
The information may be transmitted from a unit.

The work amount W of each task_nThinning based on
Total work load WA when not performing _minIs calculated.
Step 3).

Total work load WA without thinning-out
_It is determined whether or not _min exceeds the total work WP that can be processed by the processor (step 4).

Total work load WA without thinning-out
_{If min} does not exceed the total work WP that can be processed by the processor, each task is executed without thinning out (step 5).

Total work load WA without thinning-out
If _{the min} exceeds the total work WP processor can process, on the basis of the workload W _n of the maximum thinning ratio A _n and each task of each task, total work WA at maximum thinning
Calculate _max (step 6).

It is determined whether the total work amount WA _max at the time of the maximum thinning exceeds the total work amount WP that can be processed by the processor (step 7).

[0035] If the total amount of work WA _max at the time of maximum thinning does not exceed the total amount of work WP processor is capable of processing, the processor can process the total amount of work WP, maximum thinning ratio A _n and each of each task and workload W _n tasks, on the basis of the above equations 1 and 2, to calculate the thinning ratio B _n of each task (step 8).

Then, each task is executed in the thinning processing mode corresponding to the thinning rate _Bn of each task (step 9).

If it is determined in step 7 that the total work amount WA _max at the time of the maximum thinning exceeds the total work amount WP that can be processed by the processor, the task with the lower priority is put into a waiting state, and the number of tasks is set to 1 (Step 1
0). Then, the process returns to step 2, and the processes after step 2 are performed again.

[0038]

According to the present invention, it is an object of the present invention to provide a task control method for a multimedia processor which enables each task to be executed in a well-balanced manner even when the total work amount increases.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a multimedia processor.

FIG. 2 is a flowchart illustrating a task control processing procedure.

[Explanation of symbols]

 10 CPU 100 Multimedia processor

Claims (2)

[Claims] 1. A task control method for a multimedia processor capable of simultaneously executing a plurality of tasks, a step of determining a maximum thinning rate for each task, wherein no thinning is performed based on a workload of each task to be executed. Calculating the total amount of work when the multimedia processor does not exceed the total amount of work that can be processed by the multimedia processor. Calculating the total work amount at the time of the maximum thinning based on the total work amount at the time of the maximum thinning-out if the total work amount at the maximum thinning-out does not exceed the total work amount that the multimedia processor can process. Based on the workload, the workload for each task, and the maximum decimation rate for each task, the total workload is processed by the multimedia processor. A step of calculating a thinning rate of each task so as to be equal to or less than a possible total work amount, and a step of executing each task in a thinning processing mode corresponding to the calculated thinning rate of each task. A task control method for a multimedia processor, comprising: Determining a priority for each task; and, if the total amount of work at the time of maximum thinning exceeds the total amount of work that can be processed by the multimedia processor,
2. The task control method for a multimedia processor according to claim 1, further comprising the step of: placing tasks in a waiting state in ascending order of priority.