JPH03218545A - Pre-loading system for main storage - Google Patents

Abstract

PURPOSE:To shorten response time by pre-loading pages on a system buffer based on the order of the pages in an index memory when a system rises. CONSTITUTION:Index information showing the order of the pages which are pre-loaded in a main storage 16 is stored in the index memory 13 and log information showing to which page access is actually made is stored in a log buffer 19 at the time of operation. Then, index information is updated at a prescribed timing by log information. When the system rises, the pages are pre-loaded on the system buffer 18 based on updated index information. Thus, the number of input/output times at the time of initially reading the pages is reduced and response time is shortened.

Description

[Detailed Description of the Invention] [Summary] Regarding the preloading method of preloading pages from a disk device to main memory, response time can be shortened by preloading frequently used pages onto main memory. The purpose of this system is to provide a method for preloading pages into main memory that can be preloaded from a disk device to the main memory of a computer. The computer has a log buffer that stores information on whether pages have been accessed and updates the index memory, and a system buffer that stores accessed pages in the main memory. The system buffer is configured to preload pages into the system buffer based on the order of the pages.

[Industrial Application Field] The present invention relates to a preloading method for preloading pages from a disk device to a main memory.

Computer applications that use databases and files have long been required to reduce the number of inputs and outputs and speed up response times. Therefore, it is desirable to reduce the number of inputs and outputs even when starting up the system to further shorten the response time.

[Prior Art] As a conventional main memory loading method, there is one shown in FIG. 4, for example.

In FIG. 4, 1 is a computer, 2 is a CPU, 3 is an input/output control device, and 4 is a main memory. 5 is a disk device, and the disk device 5 reads data or records data according to instructions from the computer 1.

In a system that uses databases and files using such a disk device 5, a system buffer 6 is provided on the main memory 4, and pages once read from the disk device 5 into the main memory 4 are likely to be accessed again. , are secured on the system buffer 6. Then, when that page is accessed again, no input/output is required. In this way, response time is made faster.

[Problems to be Solved by the Invention] However, in such conventional main memory loading methods, pages once read into main memory are held in the system buffer; Since the page is not preloaded into memory, the first time the page is loaded, the page must be input/outputted, resulting in a long response time.

The present invention has been made in view of these conventional problems, and provides a main memory storage system that can shorten response time by preloading frequently used pages onto the main memory. It is intended to provide a preloading method.

[Means to solve the problem] FIG. 1 is a diagram explaining the principle of the present invention.

In FIG. 1, 11 is a computer, 12 is a disk device,
13 is an index memory that stores the order of pages to be preloaded from the disk device 12 to the main memory 16 of the computer 11; 19 is a log buffer that stores which pages have been accessed during operation and updates the index memory 13; A system buffer 18 holds accessed pages and is preloaded with pages based on the order of pages in the index memory 13 when the system is started up.

[Operation] In the present invention, index information indicating the order of pages to be preloaded into the main memory is stored in the index memory, while log information indicating which pages were actually accessed during operation is stored in the log buffer. remember,
The index information is updated at a predetermined timing using this log information. When the system is started up, pages are preloaded into the system buffer based on the updated index information.

Therefore, when loading a page for the first time, the number of inputs and outputs can be reduced, and as a result, response time can be shortened.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIGS. 2 and 3 are diagrams showing one embodiment of the present invention.

In FIG. 2, 11 is a computer, and 12 is a disk device such as a magnetic disk device or an optical disk device.The disk device 12 is connected to the computer 11 and reads and writes data according to instructions from the computer 11. An index memory 13 and a log file 14 are provided within the disk device 12.

The index memory 13 is for storing the order in which pages are to be preloaded.

The log file 14 is for holding log information regarding page access during operation.

That is, log information regarding page accesses is temporarily held in a log buffer, which will be described later, but is written to the log file 14 when the log buffer becomes full.

The computer 11 has a CPU 15, a main memory 16, and an input/output control device 17, and the main memory 16 includes a system buffer: 71
8 is provided.

The system buffer 18 is for holding accessed pages in the main memory 16. Furthermore, when the system is started up, pages corresponding to the system buffer are preloaded onto the system buffer 18 based on the order of the pages in the index memory 13.

19 is the log buffer provided in the computer 11, and the log buffer 719 is for storing which pages are accessed during operation. As described above, log information regarding this page access is temporarily held in the log buffer 19, but when the log buffer 19 becomes full, it is written to the log file 14.

The index information in the index memory 13 is updated as a packed job regardless of the application being operated based on the log information in the log buffer 19 or log file 14. Various timings can be considered for updating, such as when the amount of log information reaches a certain amount, or every time a certain amount of time has elapsed.

Next, the operation will be explained.

It is assumed that there are, for example, five system buffers 18 that hold accessed pages in the main memory 16. It is also assumed that the index information in the index memory 13 at the time of system startup is as shown in FIG. 3(A). Note that the numbers in FIG. 3 indicate page IDs.

Therefore, at the time of system startup, the system buffer 18 contains five pages from the beginning of the index information, that is, page ID 55. 3. 28.15.86
will be preloaded.

After that, the system is operated, and when the order of pages accessed during this operation is indicated by page IDs, these page IDs are 7, 35, 22, 28, 7, 86, 55.8. It is stored in the log buffer 19 or log file 14 as log information. When a certain amount of log information is reached or every time a certain amount of time elapses, the index information in the index memory 13 is changed to, for example, LRU (Least Rec) based on the log information.
entl7Used ). In other words, if we consider log information to be LRU, the page priorities are 8.55.86.7.28.22.35, so index information is 8, 55, 86, 7, 28, 22, 35, 3,15,・
... (see Figure 3 (B)).

Then, when the next system is started up, 8,55.86
．． 7.28 is preloaded into the system buffer 18.

In this way, frequently used pages are loaded into the system buffer 18 in advance, so that when reading the first page, the number of inputs and outputs can be reduced and the response time can be shortened. Incidentally, since updating of index information can be performed as a backup job, the possibility of causing overhead can be reduced. Furthermore, since this index information is related to efficiency, there is no need to perform troublesome processing related to maintaining consistency.

[Effects of the Invention] As described above, according to the present invention, index information indicating the order of pages to be preloaded is updated based on page access log information, and when the system is started up, pages are updated based on the index information. By preloading the page into the system buffer, it is possible to reduce the number of inputs and outputs when the page is first read, and as a result, the response time can be shortened.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention; Figure 3 (A). (B) is a diagram showing index information, FIG. 4 is a diagram showing a conventional example. In the figure, 11... Calculator, 12... Disk device, 13...index memory, 14...Log file, 15...CPU, 6...main memory, 7... Input/output control device, 8... System buffer, 9...Log buffer.

Claims (1)

[Claims] From the disk device (12) to the main memory (1) of the computer (11)
An index memory (13) for storing the order of pages to be preloaded in the disk device (13) is connected to the disk device (13).
2) has a log buffer (19) in the computer (11) that stores which pages are accessed during operation and updates the index memory (13), and also stores accessed pages. A system buffer (18) is provided in the main memory (16) to store data, and the system buffer (18)
A preloading method to main memory characterized by preloading pages.