JPH0734186B2 - Cash system - Google Patents

Description

The present invention relates to a cache system, and more particularly to an in-program cache system created in a program data area on a main memory.

[Conventional technology]

Conventionally, an application program (hereinafter simply referred to as a program) that frequently reads data from a data file or writes data to the data file
When a read request or a write request for the data on the data file is generated during execution, has issued an input / output (I / O) instruction for the data file each time.

Even if the data file is configured on the disk device and the disk cache is used, I / O to the disk cache is faster than I / O to the disk, but it takes longer than disk I / O to execute when a mishit occurs. It was hanging.

[Problems to be solved by the invention]

In the conventional program I / O instruction processing method described above, I / O
When a large number of instructions are issued, the disk device I / O is slower than the central processing unit (CPU) I / O, so the disk I / O time deteriorates the program turnaround time (TAT). .

Further, even if the disk cache is used to reduce the disk I / O time, if the job E issues an I / O command at the timing p as shown in FIG. Frequently because it is abandoned when the CPU issues an instruction to the IOP (Input Output Processor)
If there is an I / O command, the effective CPU time of job E out of the allocated CPU time of job E becomes shorter, and job E becomes invalid C
There is a drawback that the proportion of PU time increases and the usage of CPU allocation becomes inefficient.

On the other hand, if you want to eliminate almost all I / O instructions, you have to load all the data file images into the program, and if the amount of data is huge, page I / O will occur due to the use of virtual space and CPU performance will increase. However, there is a problem in that the

In view of the above points, an object of the present invention is to cache data in a data file, which is read or written many times during program execution, in a program data area in advance, and
It is to provide a cache system that suppresses the number of times.

[Means for solving problems]

The cache system of the present invention includes an input means for inputting a data item to be read or written many times out of the data on a data file designated from the outside when the program is executed, and the data item input from the input means. Based on the cache management information when a read command or a write command is issued from the program, a cache creating unit that reads the corresponding data from the data file in advance and creates a cache and cache management information in the program. Judging means for judging whether necessary data is in the cache; and data reading means for acquiring a data from the cache or the data file and passing it to the program based on the judgment by the judging means in the case of a read command. , For writing instructions And data writing means for writing data from the program into the cache or the data file based on the determination by the determination means,
Data copy means for copying all cache data from the cache to the data file based on the cache management information at the end of the program.

[Action]

In the cache system of the present invention, the input means inputs the data item to be read or written many times out of the data on the data file designated from the outside when the program is executed, and the cache creating means is input from the input means. Based on the data item, the corresponding data is read in advance from the data file, a cache and cache management information are created in the program, and the necessary data based on the cache management information when the judgment means issues a read command or a write command from the program. Is in the cache, and when the data reading means is a read instruction, the data is obtained from the cache or the data file based on the judgment by the judging means and passed to the program, and when the data writing means is a write instruction. Based on the judgment by the judgment means There writes data from the program to the cache or data files, the data copying means for copying the entire cache data from the cache based on the cache management information upon termination of the program data file.

〔Example〕

 Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. The cache system according to the present embodiment has an input means 1 for inputting a data item designation a of data to be read or written many times among data on a data file A designated from the outside when a program (not shown) is executed. And cache creating means 2 for reading the corresponding data c from the data file A in advance based on the specified data item b input from the input means 1 and creating cache management information B and cache C in the program, and reading from the program When the instruction d or the write instruction e is generated, the determination means 3 for determining whether the necessary data is in the cache C based on the cache information f from the cache management information B, and the determination means for the read instruction d. The file data h of the data file A or the file A data reading means 4 to be passed to the program won read data j from the cache data i Gerhard C, cache based on a determination result by the determination unit 3 in the case of a write command e g C or data file A
Data writing means 5 for writing write data k from the program to the program, and data copying means 6 for copying all cache data m from the cache C to the data file A based on all the cache information l of the cache management information B at the end of the program. It consists of and.

Next, the operation of the cache system of this embodiment configured as described above will be described.

The input means 1 inputs, from the outside, a data item designation a of data to be read or written many times among the data on the data file A.

The cache creating means 2 receives the designated data item b from the input means 1, reads the data c corresponding to the designation from the data file A, and cache management information B (items registered in the cache, position in the cache, used amount, etc.). ) And cache C.

Upon receiving a read command d from a program (not shown), the judging means 3 inputs the cache information f from the created cache management information B and judges whether the read-requested data is in the cache C or not. To do. Further, when the judging means 3 receives the write command e from the program, the judging means 3 similarly judges whether or not the data requested to be written is in the cache C.

The data reading unit 4 reads the file data h from the data file A if the data requested to be read is not in the cache C based on the judgment result g of the judgment unit 3.
If it is in the cache C, the cache data i is read from the cache C and the read data j is passed to the program.

The data writing unit 5 writes the write data k passed from the program to the data file A if the data requested to be written is not in the cache C based on the determination result g of the determination unit 3, and also in the cache C. If there is, the write data k passed from the program is written in the cache C.

The data copying means 6 obtains all the cache information 1 from the cache management information B at the end of the program, and writes all the cache data m of the cache C into the data file A based on the obtained cache information 1.

〔The invention's effect〕

As described above, according to the present invention, data on a data file, which is read or written many times during program execution, is cached in the program data area in advance, and I / O to the data file is minimized to reduce the normal I / O. By replacing the / O instruction with the I / O instruction for the in-program cache in the main memory, the allocated CPU time for the program can be efficiently used and the TAT of the program can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a timing chart showing an example of inefficient CPU utilization. In the figure, 1 ... input means, 2 ... cache creating means, 3 ... judging means, 4 ... data reading means, 5 ... data writing means, 6 ... data copying means, A ... data file, B ... cache management information, C ... cache, a ... data item designation, b ... designated data item, c ... data, d ... read command, e ... write command, f ... cache information, g ... ... Judgment result, h ... file data, i ... cache data, j ... read data, k ... write data, l ... all cache information, m ... all cache data.

Claims (1)

[Claims] 1. An input means for inputting a data item to be read or written many times among data on a data file designated externally when executing a program, and based on the data item input from this input means. Cache creating means for reading the corresponding data from the data file in advance and creating a cache and cache management information in the program, and necessary data based on the cache management information when a read command or a write command is issued from the program Means for determining whether or not is in the cache, and data read means for acquiring data from the cache or the data file and passing it to the program based on the determination by the determination means in the case of a read command, and In the case of an instruction, the determination means Data writing means for writing data from the program to the cache or the data file based on the judgment by the above, and copying all cache data from the cache to the data file based on the cache management information at the end of the program. A cache system comprising: a data copying unit.