JP2006338409A - Compressed data transfer method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize a data transfer method while considering the whole of a series of processing consisting of compression, transfer, and decompression, transferring performance of a communication means, a buffer capacity of data receipt decompression processing and the like while increasing transfer speed during compressed data transfer between a programming assist device and a built-in apparatus. <P>SOLUTION: In this compressed data transfer method, the programming assist device and the built-in apparatus are connected together via a transmission path, and data are compressed to be transmitted from the programming assist device to be received and decompressed by the built-in apparatus. The programming assist device notifies a data size and a transmission sequence of the respective compressed data files to be transmitted to the built-in apparatus before transmission, and then, transmits the compressed data files sequentially. According to the data size and the transmission sequence, which are notified by the programming assist device, of the transmitted respective compressed data files, communication performance of the transmission path, an available buffer capacity, other processing load conditions, and the like, the built-in apparatus selects an optimum task from a plurality of tasks with different priority for performing decompression processing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a compressed data transfer method and a compressed data transfer system between a programming support device and an embedded device.

  Conventionally, data processing has been performed by connecting information processing apparatuses via transmission lines. Comparing the processing speed of the information processing device and the transfer speed of the transmission path, the transfer speed of the transmission path is significantly lower. Therefore, when exchanging large data, the information processing equipment performs processing such as compression and decompression on the data. It is a common data transfer technique to exchange data with a data size as small as possible.

In such a compressed data transfer system, various inventions and proposals have been made according to the data to be transferred and the characteristics of the system itself. Patent document 1 etc. are the examples.
Patent Document 1 discloses a system for transferring image data between information processing apparatuses. When the information processing apparatus on the transmission side compresses a single image, the image is divided into a plurality of regions and compressed, and decoding information is created simultaneously with the compression. Decryption information is transferred together with the compressed data, and the information processing apparatus on the receiving side decompresses from a portion that is desired to be displayed quickly, such as a character portion in an image, based on the decryption information. This system is characterized by the fact that it is decompressed from data corresponding to a high information area including character information in an image and presented to an image viewer, etc., and it successfully solves the requirements in the information presentation system. It is an example.

  In addition, a programming support device and an embedded device are connected via a transmission line, and control programs and data of the embedded device are frequently exchanged. Embedded equipment means industrial equipment, home appliances, etc., and means that a computer system for realizing a specific function is incorporated. Unlike general-purpose computer systems such as personal computers, the built-in computer system is characterized in that required functions and performance are extremely limited, and there are strong restrictions on available resources due to cost limitations. Generally, it consists of an inexpensive CPU, a small amount of memory, and a ROM for storing a program.

  In the conventional compressed data transfer method between the programming support device and the embedded device, all the transfer files are first compressed individually, and then transferred in the order of ascending order of the file names, for example, and the receiving side has received all the files. Later, thawing started. The outline is shown in FIG. Data is transferred from a terminal such as a personal computer including software such as a programming support tool to the embedded device terminal through a plurality of transfer paths.

  In recent years, a method of improving this method and shortening the entire transfer processing time by performing parallel processing by overlapping compression, transfer, and decompression processing is often used. FIG. 4 shows this flowchart. As shown in the figure, when transferring three data, the data 1 starts to be transferred when the data 1 is compressed. At the same time, data 2 is compressed. When the data 1 is received by the receiving side, the data 1 is decompressed and the data 2 is transferred at the same time. In this way, the overall transfer processing time can be shortened by performing parallel processing in which each processing is overlapped. This method is typified by multi-task processing in the operating system μITRON, which is often used in embedded devices. Scheduling based on priority and internally defined timing so that other processing is not significantly delayed by one processing delay. Is to be done.

  However, if the embedded device is a device that performs processing that requires a high degree of real-time performance, such as a programmable controller or an industrial robot, the user data downloaded during operation, program update processing, etc. However, since other real-time processing is being executed, the processing capacity of the CPU cannot be largely allocated to the transfer processing or compression processing itself. However, since the download time of programs and data is regarded as a simple waiting time for the user, it is always required to increase the speed as much as possible.

  Devices that perform processing that requires a high degree of real-time often have a plurality of relatively large programs and user data, and these data are often related to each other. As an example, a program for an embedded device program is composed of a main routine and a subroutine, each of which is stored as a file, and the operating embedded device must update the program online. It is. In such a case, the relevant data, such as the main routine and subroutine, is compressed, transferred, and decompressed as a series of transfer processes, and then fetched as valid program data on the device side and updated at the same time. It is necessary to reflect as a group. In other words, not only shortening the individual transfer time that increases according to the amount of transfer data, but also optimization of the overall processing time including the transfer of a plurality of block data and the compression and decompression processing performed at the same time is required. .

Further, when the embedded device has a plurality of different communication interfaces such as USB (Universal Serial Bus), RS-422, and Ethernet (registered trademark), the data transfer processing performance varies greatly depending on the respective communication means. Comparing the transfer speed, it can be said that the Ethernet (registered trademark) of 100 Mbps and the RS-422 serial communication of 19.2 Kbps are greatly different, and comparing the packet size, the maximum is 1500 bytes for TCP / IP and 1024 bytes for USB. This is also a packet, and this also causes a difference in transfer processing performance. Another factor that determines the transfer processing performance is the size of the buffer capacity that can be prepared for data transfer and decompression processing on the embedded device side. Considering these things, when transferring compressed data, it is required to perform an optimal compressed data transfer process in consideration of the transfer processing capability of the communication means and the buffer capacity that can be prepared for the decompression process. It can be said. In addition, with regard to the decompression process on the embedded device side, if the decompression process is a common process regardless of multiple communication paths, and if a high priority is assigned to the decompression process unavoidably, for example, high-speed In the case of a network, the decompression process is frequently called, which may interfere with the process that requires real-time processing, and assigning high processing performance to a low-speed network will cause the process to be performed instantaneously and quickly. Although it seems to end, there is actually a lot of wasted time. Therefore, it is necessary to optimize the assignment of the priority of the decompression process.
JP 2000-13610 A

  Therefore, in view of the above-described problems, the present invention has an object of performing a whole series of processes of compression, transfer, and decompression while satisfying the high-speed data transfer process in the compressed data transfer between the program creation support apparatus and the embedded device. In view of this, another object is to propose a data transfer method that can be optimally adjusted in consideration of the transfer processing performance of the communication means and the buffer capacity that can be prepared for data reception and decompression processing.

  In order to solve the above-described problems, in the present invention, a program creation support apparatus and an embedded device are connected by a transmission line, and a plurality of block data files such as programs and user data are filed from the program creation support apparatus on the transmission side. In the compressed data transfer method in which data is exchanged by compressing and transferring in units and decompressing with an embedded device on the receiving side, the program creation support apparatus prior to transferring a plurality of compressed data files, Informs the embedded device of the data size and transmission order of the file to be transmitted, and then performs data transfer. The embedded device compresses / transfers data from the data size and transmission order of the file notified from the program creation support device. Consider the efficiency of parallel processing of a series of decompression processes, and transfer performance of the transmission line That the buffer capacity, consideration of the load status of the other processing, to determine the processing priority of the tasks to decompression processing, by executing the decompression process, and to optimize the processing of the embedded device side.

  According to one aspect of the present invention, a programming support device and an embedded device are connected via a transmission line, data is compressed from the program creation support device and transmitted, and the embedded device receives and decompresses the data to exchange data. The program creation support apparatus notifies the embedded device of the data size and transmission order of each file to be transmitted before transmitting a plurality of compressed data files, and then compresses the compressed data file. The data file is sequentially transmitted, and the embedded device notifies the program creation support device of the data size of each file to be transmitted, information about the transmission order, communication performance of the transmission path, available buffer capacity, and other Select the optimal task from multiple tasks with different priorities based on the processing load status and assign decompression processing. To perform the decompression processing to the task, characterized in that. As a result, on the embedded device side, based on the file information and transmission order notified in advance, the communication performance of the transmission path, the buffer capacity that can be prepared for data reception and data decompression, the load status of other processes, It is possible to select an optimal task from different tasks and assign the decompression process, thereby improving the processing margin on the embedded device side while optimizing the processing time required for data transfer.

  According to one aspect of the present invention, a programming support device and an embedded device are connected via a transmission line, data is compressed from the program creation support device and transmitted, and the embedded device receives and decompresses the data to exchange data. A compressed data transfer system, wherein the program creation support apparatus incorporates a compression means for compressing data and a data size and a transmission order of each file to be transmitted prior to transmitting a plurality of compressed data files. A notification means for notifying the device, and a transmission means for sequentially transmitting the compressed data file. The embedded device is assigned various processes such as data decompression and real-time processing, and is assigned based on the priority. A plurality of tasks for executing processing, and data of each transmitted file notified by the program creation support device And a task scheduler that determines an optimum task to which the decompression process is assigned from information on the transmission order, the communication performance of the transmission path, the buffer capacity that can be prepared, and the load status of other processes. . As a result, on the embedded device side, based on the file information and transmission order notified in advance, the communication performance of the transmission path, the buffer capacity that can be prepared for data reception and data decompression, the load status of other processes, It is possible to select an optimal task from different tasks and assign the decompression process, thereby improving the processing margin on the embedded device side while optimizing the processing time required for data transfer.

  According to the present invention, in compressed data transfer between a terminal device such as a programming support tool and an embedded device, on the embedded device side, information on the compressed data file notified from the terminal device before the transfer of the data body and the transmission order, Select the optimal task from tasks with different priorities based on the communication performance of the transmission path used for data transfer, the buffer capacity available on the embedded device, and the load status of other processing in the embedded device. It is possible to assign decompression processing, and this improves the margin of processing on the embedded device side while optimizing the series of data transfer processing time required to transfer compressed data and decompress it Is possible.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows the configuration of the present invention. A programming support device 1 having software such as a programming support tool and the embedded device 2 are connected by a transmission path A or B via respective communication interfaces 14 and 24. The transmission lines are not always connected by a plurality of transmission lines, but indicate that a plurality of transmission lines can be used. That is, the transmission path used for data transfer is determined depending on which transmission path the user uses to connect the support apparatus 1 and the embedded device 2.

  The programming support device 1 includes a compression unit 11 that compresses a program file to be transferred and a user data file 10, and a notification unit 12 that notifies the embedded device 2 of the data size and transfer order of the file compressed and transferred by the compression unit 11. And transmitting means 13 for transmitting the compressed file.

  The embedded device 2 includes a buffer 23 used for processes such as reception of data transferred from the programming support apparatus 1 and decompression of compressed data, and a task 22-1 to which various processes such as data decompression and real-time processing are assigned. 22-2 and 22-3, and a task scheduler 21 that determines which process is assigned to each task. Each task has a different priority. The task scheduler 21 supervises all task assignments in the embedded device 2, and in particular, information on the data size and transmission order of each transmitted file notified by the program creation support apparatus 1, and transmission The optimum task to which the decompression process is assigned is determined from the communication performance of the path, the buffer capacity that can be prepared for data reception and data decompression, and other processing conditions.

The compressed data transfer of the present invention will be specifically described below.
In FIG. 1, it is assumed that the transfer speed of the transmission path A is 20 Kbps, the transfer speed of the transmission path B is 300 Kbps, and the support apparatus 1 and the embedded device 2 are connected by the transmission path B. Also, there are three tasks T1 to T3 in the embedded device 2, and these are T1, T2 and T3 in order of priority, and decompression processing is possible at processing speeds of 100 Kbps, 200 Kbps and 600 Kbps, respectively. To do.

Assume that files F1, F2, F3, F4, and F5 having file sizes after compression of 20 Kbytes, 40 Kbytes, 100 Kbytes, 40 Kbytes, and 200 Kbytes are transferred. When the transfer order is F1->F2->F3->F4-> F5, the flow of the transfer process is as follows.
(1) The transfer order and the file size of each file are notified from the support apparatus 1 to the embedded device 2.
(2) The compression, transfer, and decompression processes are sequentially performed in the order of F1, F2, F3, F4, and F5.
(3) On the embedded device side, the task scheduling of the decompression process is performed based on the processing time of the file transfer process that is subsequently performed.

  FIG. 2A shows an example of time when the compression, transfer, and decompression processes are sequentially performed in the order of F1-> F2-> F3-> F4-> F5 on the transmission line B as described above in the prior art. It is. Conventionally, the decompression process on the embedded device side is performed in one task, and the processes are performed serially. In this example, since the decompression process of F3 cannot be completed before the decompression process of F4 is started, a waiting time is generated.

  On the other hand, in the data transfer according to the present invention, referring to the transfer order of the file notified before starting the compressed data transfer, the decompression process of the file F1 is the transfer process of the next file F2, and the decompression process of the file F2 is The decompression process is scheduled based on the transfer process time of the next file to be transferred in the same manner as described below, such as the transfer process of the next file F3. That is, for example, if the decompression processing of F1 is made shorter than the transfer processing time of the next F2, the processing time is offset, so no waiting time occurs. Therefore, task assignment is performed so as to be like that. Note that, when scheduling, there is a buffer capacity sufficient for receiving and decompressing data (file), and other processing load conditions are also taken into consideration.

  FIG. 2B shows an example of time when the file is compressed, transferred, and decompressed according to the present invention. First, the file F1 is transferred, and then the file F1 is decompressed. If the decompression time of the file F1 having a file size of 20 Kbytes is made smaller than the transfer processing time of the file F2, the decompression process of the file F2 is performed. There is no waiting time before starting. The transfer processing time of the file F2 is 40 Kbytes × 8/300 Kbps = 1.06 sec because the file size of the file F2 is divided by the transfer speed of the transmission path B, and the task scheduler takes 1.06 seconds or less for the decompression processing of the file F1. Select the minimum task level required to be In this case, the file F1 decompression processing time in the task T2 with a processing performance of 200 Kbps is 20 Kbytes × 8/200 Kbps = 0.8 sec, and the file F1 decompression processing time in the task T1 with a processing performance of 100 Kbps is 20 Kbytes × 8/100 Kbps = 1. .6 sec, the task scheduler selects task T2 and assigns decompression processing. Similarly, the decompression process of the file F2 is assigned to the task T2. The task assignment for the subsequent decompression processing of the file F3 is determined by the transfer processing time of the file F4. That is, since the transfer processing of the file F4 takes 40 Kbytes × 8/300 Kbps = 1.06 sec, it is desired to allocate the decompression processing of the file F3 so that the waiting time does not occur. In this case, the task T3 having a processing performance of 600 Kbps is allocated. However, it takes 100 Kbytes × 8/600 Kbps = 1.3 sec to decompress the 100 Kbyte file F3. Since the task T3 is the highest processing performance task provided in the embedded device 2, a waiting time occurs in this case, but the task T3 is assigned to the decompression processing of the file F3. Next, the task assignment of the decompression processing of the file F4 is determined by the transfer processing time of the file F5. That is, the transfer processing time of the file F5 is 200 Kbytes × 8/300 Kbps = 5.3 sec, and even if the task T1 having a processing performance of 100 Kbps is assigned the decompression processing of the file F4, the transfer processing time of the file F5 is 40 Kbytes × 8/100 Kbps = 3.2 sec. Since it is sufficient not to generate a waiting time before starting the decompression process, the decompression process of the file F4 is assigned to the task T1. Finally, the decompression process of the file F5 having a file size of 200 Kbytes is assigned to the task T3 having the highest processing performance because there is no transfer process that follows.

As described above, the task scheduling is performed in consideration of the time required for the decompression process and the transfer time of the next file on the embedded device side, and as shown in FIG. 2A and FIG. It is possible to increase the efficiency of the compressed data transfer process.
In the above description, the task allocation is mainly performed according to the transfer processing time of the file to be transferred next. However, depending on the free space of the buffer and other load conditions, other processes may be performed. There is a case where task assignment is performed so that processing is prioritized over decompression processing. In other words, devices that should guarantee real-time performance are configured to optimize the processing time after suppressing the decompression task selection to the lowest possible level, and other processing is not performed regularly. In a device in which a process with a high priority runs, information on whether or not the high priority process is being executed may be used as a material for determining task assignment. As a result, the data transfer process can be performed without affecting other processes, and the processing time can be optimally suppressed.

  As described above, according to the present invention, in compressed data transfer between a terminal device such as a programming support tool and an embedded device, information on the compressed data file notified from the terminal device before the data body is transferred on the embedded device side. Based on the order of transmission, the communication performance of the transmission path used for data transfer, the buffer capacity that can be prepared on the embedded device side, and the load status of other processes in the embedded device It is possible to assign the decompression process by selecting the optimal task, which optimizes the series of data transfer processing time required to transfer the compressed data and decompress it, while leaving the processing margin on the embedded device side It is possible to improve the degree.

It is a figure which shows the structure of this invention. (A) is a figure which shows the time example of the compression, transfer, and decompression | decompression process in a prior art, (b) It is a figure which shows the time example of the compression, transfer, and decompression | decompression process in this invention. 1 is a diagram illustrating an example of a system that performs data transfer. It is a figure which shows the flow of the compression, transfer, and decompression | decompression process in the conventional system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Programming support apparatus 2 Embedded apparatus 10 Program file, user data file 11 Compression means 12 Notification means 13 Transmission means 14 Communication interface 21 Task scheduler 22-1 to 22-3 Task 23 Buffer 24 Communication interface

Claims (2)

A compressed data transfer method in which a programming support device and an embedded device are connected by a transmission path, data is compressed and transmitted from the program creation support device, and data is exchanged by receiving and decompressing the embedded device,
Prior to transmitting a plurality of compressed data files, the program creation support device notifies the embedded device of the data size and transmission order of each file to be transmitted, and then sequentially transmits the compressed data files,
The embedded device is notified from the program creation support device, the data size of each file to be transmitted, information about the transmission order, the communication performance of the transmission path, the buffer capacity that can be prepared and the load status of other processing, Select an optimal task from a plurality of tasks with different priorities, assign a decompression process, and let the task perform the decompression process.
A compressed data transfer system characterized by this. A compressed data transfer system that connects a programming support device and an embedded device via a transmission line, compresses and transmits data from the program creation support device, receives and decompresses the data by the embedded device, and exchanges data.
The program creation support device includes:
Compression means for compressing data;
Prior to transmitting a plurality of compressed data files, a notification means for notifying the embedded device of the data size and transmission order of each file to be transmitted;
A transmission means for sequentially transmitting the compressed data file;
With
The embedded device is
A plurality of tasks that are assigned various processes such as data decompression and real-time processing, and execute the assigned processes based on priority,
The optimal allocation of decompression processing based on the data size and transmission order information of each file to be transmitted, notified by the program creation support device, and the communication performance of the transmission path, the buffer capacity that can be prepared, and the load status of other processing A task scheduler that determines which tasks are
A compressed data transfer system comprising:

Images