JPS63313252A - Cache system - Google Patents

Abstract

PURPOSE:To suppress the number of times of I/O operation to/from files by previously caching data of a file to be frequently read out or written at the time of executing a program in a program data area. CONSTITUTION:At the time of receiving a reading instruction (d) from the program, a decision means 3 inputs cache information (f) from formed cache management information B to decide whether data to be requested to be read out exists in a data file A or a cache C. A data reading means 4 reads out file data (h) or from the data file A or cache data (i) from the cache C based on the decided result (g) of the means 3 and transfers read data (j) to the program. A writing instruction (e) is similarly processed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cache system, and particularly to an in-program cache system created in a program data area on a main memory.

[Conventional technology]

Conventionally, an abduction program (hereinafter simply referred to as a program) that frequently reads data from a file and writes data to a refile, when a read request or write request for data on a file occurs during execution, Input/output to the file (Il)
o) He was giving orders.

Even when a file is configured on a disk device and a disk cache is used, Ilo for the cache is faster than Ilo for the disk, but when a miss hint occurs, it takes longer to execute than disk I10.

(Problems to be solved by the invention) In the conventional program I10 instruction processing method described above,
If the I10 command is issued many times, the Ilo of the disk device is slower than the Ilo of the central processing unit (CPU), so there is a disadvantage that the disk 110 time deteriorates the program turnaround time (TAT).

Furthermore, even if a disk cache is used to reduce the disk time, if job E issues an I10 command at timing p, as illustrated in FIG. (I npu
Since the command is abandoned as soon as it is issued to the I10
If there is a command, the effective CPU time of job E out of the allocated CPU time of zip E will be short (as a result, the ratio of invalid CPU time of job E will increase, making the use of the allocated CPU time inefficient) There is a drawback.

On the other hand, if you try to eliminate almost all I10 instructions, you will have to import all file images into the program, and if the amount of data is huge, page I10 will occur due to the use of virtual space, making it impossible to fully utilize the performance of the CPU. There is a problem.

In view of the above-mentioned points, an object of the present invention is to cache data on a file that is read or written many times during program execution in advance in a program data area, thereby suppressing the number of times the file is cached. The goal is to provide a system.

[Means for solving problems]

The cache system of the present invention includes an input means for externally inputting a data item to be read or written many times among data on a specified file when a program is executed, and a data item input from the input means. cache creation means for reading corresponding data from the file in advance based on the information and creating a cache and cache management information in the program; a determining means for determining whether data is in the cache or on the file; and in the case of a read command, data acquired from the cache or the file based on the determination by the determining means and data to be passed to the program. reading means; data writing means for writing data from the program into the cache or the file based on the determination by the determining means in the case of a write command; and data copying means for copying all cache data from the cache data to the file.

[Effect]

In the cache system of the present invention, the input means inputs a data item to be read or written many times from data on a file specified from the outside when executing a program, and the cache creation means inputs data items input from the input means. A cache and cache management information are created in the program by reading the corresponding data from a file in advance based on the item, and when the judgment means issues the command or write command one after another from the program, the necessary data is determined based on the cache management information. It is determined whether the data is in the cache or on the file, and when the data reading means is a read command, the data is acquired from the cache or the file based on the judgment by the determining means and passed to the program, and the data writing means receives the write command. In this case, the data from the program is written to the cache or file based on the judgment by the judgment means, and the data copying means copies all the cache data from the cache to the core and file based on the cache management information when the program ends.

【Example〕

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

FIG. 1 is a block diagram showing one embodiment of the present invention. The cache system of this embodiment includes an input means 1 for inputting a data item designation a of data to be read or written many times among data on file A that is input from the outside when a program (not shown) is executed. , input means l
cache creation means 2 for reading corresponding data C from data file A in advance and creating cache management information B and cache C in a program based on specified data items inputted from the program; and a read command d or write command from the program. determining means 3 for determining whether necessary data is in cache C or data file A based on cache information r from cache management information B when e is issued; and determining in the case of read command d. Data file A based on the judgment result g by means 3
data read means 4 that acquires read data j from file data h or cache data i of cache C and passes it to the program; Data writing means 5 writes write data k from the program to f!, and all cache information f! of the cache management information B at the end of the program. ! The data copying means 6 copies all the cache data m from the cache C to the data file A based on tt.

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

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

The cache creation means 2 receives the designated data item from the input means 1, reads the data C corresponding to the designation from the data file A, and creates cache management information B (items registered in the cache, 2, positions in the cache). , usage amount, etc.) and cache C.

When the determining means 3 accepts a read command d from a program (not shown), it inputs cache information f from the created cache management information B, and determines whether the data requested to be read is on the data file A. Determine whether it is in cache C. Further, when the determining means 3 accepts a write command e from the program, it similarly determines whether the data requested to be written is in the data file A or in the cache C.

The data succession means 4 reads either the file data h from the data file A or the cache data j from the cache C based on the determination result g of the determination means 3,
Pass read data j to the program.

The data writing means 5 writes the write data k passed from the program into either the data file A or the cache C based on the judgment result g of the judgment means 3.

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

〔Effect of the invention〕

As explained above, the present invention caches data on a file that is read or written many times during program execution in advance in the program data area, minimizes Ilo for the file, and improves the normal I1
By replacing the 0 instruction with the I10 instruction for the in-program cache in the main memory, the CPU time allocated to the program can be used efficiently and the TAT of the program can be improved.

[Brief explanation of the drawing]

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 usage. In the figure, 1...input means. 2... Cache creation means, 3... Determination 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 specification, b...Specified data item, C...Data, d...Read instruction, e...Write instruction, 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] An input means for inputting a data item to be read or written multiple times among data on a file specified from the outside when executing a program, and an a cache creation unit that reads relevant data from the file in advance and creates a cache and cache management information in the program; and a cache creation unit that reads relevant data from the file in advance and creates a cache and cache management information in the program; and when a read command or a write command is issued from the program, the necessary data is determining means for determining whether the data is in the cache or on the file; and data reading means for acquiring data from the cache or the file based on the determination by the determining means in the case of a read command and passing it to the program. and a data writing means for writing data from the program to the cache or the file based on the determination by the determining means in the case of a write command, and data writing from the cache based on the cache management information upon termination of the program. A cache system comprising: data copying means for copying all cache data to a file.