JPH04290114A - Memory control system for computer - Google Patents

Abstract

PURPOSE:To increase the program execution speed by decreasing the frequency of access to an auxiliary storage device under memory control which performs paging. CONSTITUTION:A main storage device as a real storage device and the auxiliary storage device as an external storage device are used and an execution type program which is divided into blocks of size corresponding to memory allocation units of the main storage device is paged in the block units between said main storage device and auxiliary storage device. In this memory control system for the computer, information regarding the frequencies of the use of the respective blocks is gathered by executing said program. When said program is started after the information gathering, blocks which are high in the use frequency are allocated preferentially to the main storage device according to the information regarding the use frequencies of the respective blocks and blocks which are low in use frequency are allocated to the auxiliary storage device from the beginning.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory management system for a computer, and more particularly to a paging type memory management system.

0002

2. Description of the Related Art A memory management system using a virtual memory system that performs paging is known as one of the memory management systems that a computer operating system has to effectively utilize the limited memory space of a main storage device. This memory management system divides an executable program into blocks (pages) of a size corresponding to the memory allocation unit (page frame) of the main storage device, and uses the divided blocks as real storage devices. Programs are read and written between the main storage device and an auxiliary storage device as an external storage device.

[0003] In a memory management system using a virtual memory system that performs paging, when an executable program, that is, a target program is started, this target program is allocated to free space in the main storage device in block units in the order in which it is written. , if there is no free space in the main memory, blocks of other programs that have already been allocated in the real memory are paged out to the auxiliary memory, and then blocks of the target program are allocated, or the blocks of the target program are If the memory capacity of the target program is larger than the free memory capacity of the main memory, only some blocks of the target program are allocated to the main memory, and the remaining blocks that could not be allocated to the main memory are allocated to the auxiliary memory. The allocation is performed, thereby making it possible to effectively utilize the memory space of the main storage device and to execute a target program with a memory capacity larger than the memory capacity of the free area of the main storage device.

0004

[Problems to be Solved by the Invention] Conventionally, however, in the above-mentioned memory management system, the target program is simply allocated to the main memory in block units in the order in which the program is written, that is, in order from the beginning of the program. On the other hand, each block of the target program is not arranged in order of frequency of use during program execution, so blocks that are used less frequently are allocated to the main memory, and blocks that are used more frequently are allocated to the auxiliary storage. Blocks of other programs that are used more frequently than newly allocated blocks may be paged out, that is, saved, to the auxiliary storage device.

[0005] In this case, since the blocks allocated to the auxiliary storage device are frequently used, the number of times blocks of the target program are read and written to the auxiliary storage device during program execution increases. There is a problem that the number of accesses increases and the program execution speed of the computer decreases.

The present invention was created in view of the problems in the conventional memory management system as described above, and the present invention is designed to allocate a target program divided into blocks to the main memory by taking into account the frequency of use of each block. The present invention aims to provide a memory management system that improves program execution speed by reducing the number of times an auxiliary storage device is accessed during program execution.

[0007]

[Means for Solving the Problems] According to the present invention, the above-mentioned object is achieved by using a main storage device as a real storage device and an auxiliary storage device as an external storage device, and by using a main storage device as a memory allocation unit of the main storage device. In a computer memory management system that pages an executable program divided into blocks of corresponding sizes between the main storage device and the auxiliary storage device in block units, the execution of the program causes the Collecting information regarding the usage frequency of each block, and when starting the program after collecting this information, prioritize and allocate blocks with high usage frequency to the main storage device based on the collected information regarding the usage frequency of each block. This is achieved by a computer memory management system characterized by:

[0008]

[Operation] According to the above-described memory management system, when a program is started, frequently used blocks of the program are allocated to the main memory, and less frequently used blocks are randomly allocated to the main memory. There is no.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an example of a computer capable of executing a memory management system according to the present invention. This computer has a CPU 1, a main storage device 2 as a real storage device, and a controller 3 for controlling an external storage device,
These are connected to each other by an internal bus 4. An auxiliary storage device 5 as an external storage device such as a hard magnetic disk is connected to the controller bus 3 for controlling the external storage device.

The main storage device 2 has a memory space for storing an operation system file including a memory management program for executing the memory management system according to the present invention, and a memory space for reading an executable program, that is, a target program. As shown in FIG. 2, the memory space into which the target program is read is logically divided into a plurality of page frames to which the target program can be allocated in memory allocation units, that is, page units, or in other words, block units. ing.

The auxiliary storage device 5 stores programs in executable format and logging table files related to these programs.

The operating system of this computer employs a virtual storage system, and for example, when a target program A stored as a file in the normally used area of the auxiliary storage device 5 is executed, the program A that is stored in the main storage device 2 is executed. The address space of the target program A is divided into blocks A1, A2, A3, A4, .
As shown in FIG. 2, blocks A1, A2, A3, A4, etc. are divided into blocks A1, A2, A3, A4, etc., and are divided into the main storage device 2 and a part of the auxiliary storage device 5 (swap area or external page area). The target program is allocated to each page frame of the memory space constituted by , and this target program is executed as a program with consecutive addresses on the virtual memory while the addresses are managed by the virtual memory system.

The memory management program collects information regarding the frequency of use of each block A1, A2, A3, A4, etc. by executing the object program A, and collects information regarding the frequency of use of each block A1.
, A2, A3, A4, etc. is stored in the auxiliary storage device 5, and when the target program A is started after collecting this information, each block A1, A2, A3, A4, etc. stored in the auxiliary storage device 5 is stored. Allocation management is performed in which blocks with high usage frequency are prioritized and allocated to the main storage device 2 based on the usage frequency logging table of A4....

Each block A1, A2 of the target program A
, A3, A4, etc., the memory management program of the operating system collects information on the usage frequency of blocks (pages) that have been referenced within a certain amount of time in the past, that is, within the working set, before page-out processing is performed. This is done by checking a certain block and incrementing the count value of a counter corresponding to each block, and this data is stored as a logging table file in the auxiliary storage device 5 when the execution of the target program A is completed. . This logging table file is
It may be updated each time the target program A is executed, and in this case, the frequency of use may be the average value of the frequency of use in past program executions.

It is assumed that the page-out process is executed by the memory management program of the operating system when the free memory area of the main storage device 2 becomes less than a predetermined amount while a certain program is being executed.

Therefore, if the target program A has been executed at least once before, the auxiliary storage device 5 stores a logging table indicating the frequency of use of each block, which is logged for each block by the memory management program.

When the target program A is restarted, its memory allocation is such that the address space of the target program A is divided into blocks A1 and A of the same size as the page frame of the main storage device 2.
2, A3, A4, etc., and each block is divided into main storage 2, A3, A4, etc. based on a logging table indicating the usage frequency of each block.
and a part of the auxiliary storage device 5. In this case, among the blocks A1, A2, A3, A4, etc. of the target program A, the most frequently used blocks are It is allocated with priority to storage device 2.

FIG. 2 shows that blocks A1, A3, and A4 are allocated to the main storage device 2 as frequently used blocks.
An example is shown in which block A2 is allocated to the auxiliary storage device 5.

Block A allocated to auxiliary storage device 5
2, the memory management program of the operating system pages out blocks that have not been used for a certain period of time from the main storage device 2 to the auxiliary storage device 5, frees the page frame of this, and uses this freed page. Block A2 of the auxiliary storage device 5 is paged into the frame.

Next, each block A1, A2, A3, A4, . The allocation will be explained with reference to the flowchart of FIG.

First, in order for the target program A to be executed, the memory management program stores each block A1 of the target program A in the memory space constituted by the main storage device 2 and a part of the memory usage area of the auxiliary storage device 5. ,A2,A
3, A4... is requested by the CPU 1, first, in step 1, it is checked whether a count value indicating the frequency of use of each block of the target program A is written in the logging table of the auxiliary storage device 5, that is, whether or not the usage frequency of each block of the target program A is written. It is determined whether frequency information is present or not. Program A in auxiliary storage device 5
If the usage frequency information is not stored, the process proceeds to step 2, in which the target program A is constructed from the main memory 2 and part of the memory usage area of the auxiliary memory 5 in order from the first block, as in the past. This flow is then allocated to an empty memory space. Then, the target program A is executed by the CPU 1 as in the conventional case.

On the other hand, program A is stored in the auxiliary storage device 5.
If the usage frequency information is stored, proceed to step 3, and set the total number of blocks of target program A to variable N and 1.
is assigned to the counter variable n, and a threshold value set for each operating system or program is assigned to the variable Lim, and each block A1 is assigned from the auxiliary storage device 5.
, A2, A3, A4, . . . usage frequency information is read. Then, the process proceeds to step 4, where the frequency of use of the nth (counter variable) block An is assigned to the variable f(n), and in step 5, this variable f(n) is compared with the threshold variable Lim.

If the variable f(n) is less than or equal to the threshold variable Lim in step 5, the process proceeds to step 6, and block A
If n is allocated to the memory usage area of the auxiliary storage device 5, and the variable f(n) is larger than the variable Lim,
Proceeding to step 7, block An is allocated to the main storage device 2.

Next, in step 8, 1 is added to the counter variable n, and then the process proceeds to step 9, where the variable n and the variable N
are compared. If the variable n is less than the variable N, the process returns to step 4 and the above steps are repeated. On the other hand, if the variable n becomes equal to the variable N, it is assumed that all blocks of the target program A have been allocated and this flow ends. do. Then, the CPU 1 executes the target program A.

According to the block allocation procedure as described above, only blocks whose use frequency is above a predetermined value are allocated to the main storage device 2, and blocks whose use frequency is below a predetermined value are allocated to the auxiliary storage device 5 from the beginning.

As a result, if the memory capacity of the target program is larger than the free memory capacity of the main storage device 2, the less frequently used blocks may be allocated to the main memory device 2 from the beginning, or the less frequently used blocks may be allocated to the main memory device 2 from the beginning. Blocks of other programs with high values are not saved to the auxiliary storage device 5, and as a result, the number of accesses to the auxiliary storage device 5 during program execution is reduced.

In addition to the embodiments described above, the computer memory management system according to the present invention stores each block of the target program in the main memory in the order of the most frequently used blocks within the allowable memory capacity of the main memory. It is also possible to assign it.

[0029]

As is clear from the above explanation, according to the computer memory management system of the present invention, when a program is started, frequently used blocks of the program are allocated to the main memory, and Blocks that are infrequently used are no longer randomly allocated to the device, thereby reducing the number of accesses to the auxiliary storage device during program execution and improving program execution speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a computer capable of executing a memory management system according to the present invention.

FIG. 2 is a diagram schematically showing the memory space of a computer capable of executing the memory management system according to the present invention.

FIG. 3 is a flowchart illustrating a procedure for allocating blocks to a target program in a computer memory management system according to the present invention.

[Explanation of symbols]

1 CPU 2 Main memory 3 Controller for external storage device control 4 Bus 5 Auxiliary storage device

Claims (1)

[Claims] Claim 1: Using a main storage device as a real storage device and an auxiliary storage device as an external storage device, an executable program divided into blocks of a size according to the memory allocation unit of the main storage device is blocked. In a memory management system of a computer that performs paging between the main storage device and the auxiliary storage device in units, information regarding the frequency of use of each block is collected by executing the program, and after collecting this information, A memory management system for a computer, characterized in that when the program is started, blocks that are frequently used are prioritized and allocated to a main storage device based on collected information regarding the frequency of use of each block.