JPS603224B2 - Data creation method for adjusting the number of page storage areas in page buffer memory - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for storing pages in a page buffer memory that makes it possible to easily obtain data that is effective when adjusting the size of a page buffer memory that can store multiple pages. This relates to a data creation method for adjusting the number of areas.

An input/output management program that performs random access to a direct access device has a page buffer area that can store multiple pages in main memory, and uses an appropriate algorithm to remove pages, such as LRU (Least Rec).
entryUsed) method.

In such a case, once the number of buffers is determined,
In an actual continuous use environment, it is difficult to determine which page has a proper number of storage sites, and it is difficult to adjust the number of page storage sites. The present invention is based on the above-mentioned consideration, and it is determined by what percentage that if the number of pages in the page buffer memory is increased by n, the probability that the page to be accessed exists in the page buffer memory is increased. The purpose of this invention is to provide a data creation method for adjusting the number of pages stored in a page buffer memory, which makes it possible to reasonably and easily obtain data for determining the number of pages stored in a page buffer memory.

Therefore, in the data creation method for adjusting the number of pages stored in the page buffer memory of the present invention, if the page requested by the access request source does not exist,
A virtual buffer that controls a page number stack, an access count recording section, and the page number stack and access count recording section in a page buffer memory where pages are transferred in and out of other memory devices. A control means is provided, and the virtual buffer control means performs a process of (a) checking whether the number of the page to be accessed exists in the page number stack each time page replacement is performed in the page buffer memory; (B)
If the number of the page you want to access exists in the page number stack, remove the page number from the page number stack and push the page number stack by 1.
(c) If the number of the page you want to access does not exist in the page number stack, remove the last page number from the page number stack, and and (d) processing to set the number of the page pushed out from the page buffer memory at the top of the page number stack. That is.

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a diagram showing a page number stack, a read table and a write table, and FIG. 3 is a diagram explaining the operation of the present invention.

In FIG. 1, 1 is a page buffer memory, 2 is a page buffer control device, 3 is an input/output control device, 4 is an external storage device, 5 is an access page register, 6 is an extended page register, 7 is a virtual buffer control device;
8 is the page number stack, 9 is the lead table, 10
11 indicates a write table, and 11 indicates a page access request source. Page buffer memory 1 is
It has multiple page storage areas, and a change bit field is added to the page storage area. The change bit indicates whether or not the data in the page storage area has been rewritten, and a change bit of "1" indicates that the data has been rewritten. page buffer
Memory 1 may be considered to be an area on main memory, or may be considered to be a cache memory,
Alternatively, it may be considered as the main memory itself. When a page access requester accesses a page, the page address is set in the access page register. The page buffer controller 2 uses the contents of the access page register 5 to search the page buffer memory 1. If the corresponding page does not exist in the page buffer memory 1 and there is no free page storage, the page number and change bit of the page to be created are set in the ejection page register 6. . When the creation page change bit is “1”, the input/output control device 2
The page writing function unit 3-1 writes the created page to the external storage device 4. Also, since the page to be accessed did not exist in the page buffer memory 3, the page reading function section 310 of the input/output control device 2 reads the corresponding page from the external storage device 4 and extracts the read page. The page will be stored in the page storage castle where the page was stored. A system that performs the above-mentioned operation is conventionally known, but the present invention is characterized by adding a mechanism shown by dotted lines to this type of system.

The dotted line indicates that if there are n more pages stored in the page buffer memory, the number of times pages are read from the external storage device 4 and the number of pages written to the external storage device 4 based on page creation is calculated. This is to calculate how much it will decrease. The page number stack has entries #1 to #n, and the number of the extrusion page is written in each entry. Read table 8 and write table 10 also have #1 to #n entries. The virtual buffer control device 7 controls the page number stack 8 and performs write processing to the read table 9 and write processing to the write table 101. As mentioned earlier, if the page requested by the page access request source 11 does not exist in the page buffer memory 1, the page is read from the external storage device 4, and this read data is stored in the free storage space. Alternatively, it is stored in the page storage area of the created page.

Every time such page replacement occurs, the following processing is performed. First, it is checked whether the page to be accessed is registered in the page number stack 8. As shown in Figure 3 A, the page you want to access is ## in the page number stack 8.
If the #i entry in the read table 9 is registered in The contents of the i entry are also incremented. If the number of the page you want to access is registered in the page number stack 8, after performing the process shown in Figure 3 A, remove the number of the page you want to access from the page number stack 8, as shown in Figure 3. The contents of the page number stack 8 are pushed down by 1 as shown in FIG. If the number of the page to be accessed is not registered in the page number stack 8, as shown in FIG. 3C, the data in the #n entry of the page number stack 8 is invalidated and pushed down. After the above-mentioned processing of FIG. 3A and FIG. 3A or FIG. page buffer
Information for adjusting the number of pages stored in memory can be obtained as follows.

If m (1≧n) extra page storages exist, the number of reads from the external storage device 4 should decrease by the number given by the following equation. Number of decreases = i≧. (
#i The number of times the entry is read (number of times the entry is read) and the number of times the write is decreased is similarly determined. The validity of increasing the page storage area by m can be determined by comparing the number of decreases in the number of reads or the number of decreases in writes obtained in this way with the total number of reads or writes. The present invention provides, for example, VS (VM
This can be applied to the paging supervisor of an OS that has the uaIStonege) function.

In this case, for the paging algorithm, the page buffer is real memory itself, and pages are moved in and out between real memory and the page data set directly above the direct access diamond. When the present invention is used, the following operations are performed. ○'If you want to obtain information for adjusting the number of pages stored, specify so at the time of IPL.

'21 The paging supervisor, as mentioned above,
It simulates how much the number of reads or writes decreases when the number of pages stored is increased by m, and the simulation results are written to a system log file at a predetermined timing.

'31 The system administrator analyzes the logs and determines whether the amount of memory installed is appropriate under the actual continuous use environment.

Even when thrashing occurs frequently, by using the present invention, it can be determined whether thrashing can be reduced by increasing the mounted memory capacity.

As is clear from the above description, according to the present invention, it is possible to easily and rationally create data for optimally adjusting the number of pages stored in the page buffer memory.・Brief explanation of the drawings Figure 1 is a block diagram of one embodiment of the present invention, Figure 2 is a diagram showing a page number stack read table and write table, Figure 3 explains the operation of the present invention. It is a diagram.

DESCRIPTION OF SYMBOLS 1... Page buffer memory, 2... Page buffer control device, 3... Input/output control layer, 4... External storage device, 5... Access page register, 6... Extrusion page register. Register, 7...virtual buffer control device,
8...Page number stack, 9...Read table, 10...Write table, 11...Page access request source.

O diagram Figure 2

Claims (1)

[Claims] 1. If the page requested by the access request source does not exist, the page number stack, access count recording section, and the above page number stack are stored in the page buffer memory that transfers pages to and from other memory devices. and an access count recording unit, and the virtual buffer control means performs the following operations, each time a page is replaced in the page buffer memory: (b)
If the number of the page you want to access exists in the page number stack, remove the page number from the page number stack and push the page number stack by 1.
(c) If the number of the page you want to access does not exist in the page number stack, remove the last page number from the page number stack and add 1 to the access count record section. and a process of setting the number of the page evicted from the page buffer memory at the top of the page number stack. - Data creation method for adjusting the number of page storage areas in memory.