JPH04111029A - Main storage allocation control system - Google Patents

Abstract

PURPOSE:To enhance the use efficiency of a main storage and to always obtain the stable and satisfactory performance by changing dynamically the distribution of an allocation of the main storage in accordance with a load state of a system. CONSTITUTION:A program 1 for measuring a load to a virtual storage and a file buffer is called at the time when paging and a file input/output request are generated, and load information of the number of times of a page fault and a hit rate of the file buffer, etc., is collected. Subsequently, a program 2 for controlling an allocation distribution of a main storage is called at the timing of every prescribed time and the time when paging is generated, etc., and based on the load information derived by the program 1, a distribution of an allocation of the virtual storage and the main storage to the file buffer is adjusted. Accordingly, the distribution of the main storage capacity allocated to the original virtual storage and the main storage capacity allocated to the file buffer can be changed dynamically in accordance with a load of a system derived by this function. In such a way, an optimal state can always be held.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a main memory allocation control method for a computer system having a virtual memory control function.

[Conventional technology]

Figure 3(a) shows an external storage device! ! This is an example in which a physical file access from a program 31 to a file 52 is realized as a logical file access by associating a file on 42 with a file buffer 32 on a virtual memory 41.

The file buffer 32 is associated with part or all of the external storage device 42, and logical file access is realized by referencing and updating the file buffer 32.

The contents of the file buffer 32 are reflected when the system performs input/output with the external storage device 42.

The main memory allocated to the file buffer 32 of the virtual memory 41 can be fixedly allocated to each program and buffer as shown in FIG. 3(b), or as shown in FIG. 3(C).
As shown in Figure 2, there is a method of allocating as needed without distinguishing between programs and buffers.

Note that related techniques of this type include, for example, Japanese Patent Application Laid-Open No. 62-37754.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, the allocation distribution of main memory for programs and main memory for file buffers is fixed at the time of system startup, or file buffers are also considered as part of virtual memory, and programs and buffers are not distinguished. It was either to allocate main memory without

In the virtual memory control function, when the amount of main memory allocated to a program is small, paging occurs frequently and performance deteriorates, and the larger the allocated amount, the better the performance. Similarly, for file buffers, the smaller the allocated amount of main memory, the lower the probability that data exists in the buffer, resulting in lower performance, and the larger the allocated amount, the better the performance.

In a system where the main memory allocation is fixed at system startup,
Even if the program access frequency or file access frequency changes depending on the status of the program to be executed, the main memory allocation distribution for the program and file buffer remains constant, so the main memory usage efficiency does not improve, and the program If accesses concentrate on one of the file buffers, it may become a bottleneck in overall performance.

In addition, in a method that stores file buffers in virtual memory and treats data on the original virtual memory, such as programs and work areas, and data on the file equally, as the size of the file being accessed increases, the relative program and work Since the capacity of the main memory allocated for the area becomes smaller, the frequency of occurrence of paging increases, which may lead to a decrease in performance.

An object of the present invention is to solve the above-mentioned drawbacks and realize a high-performance computer system by efficiently allocating main memory.

[Means to solve the problem]

In order to achieve the above purpose, it has a function to calculate the load on the original virtual memory, such as the number of paging times, and the load on the file, such as the probability that a file access hits the file buffer. By dynamically changing the allocation of storage capacity and main storage capacity allocated to file buffers according to the system load determined by this function, it is possible to always maintain an optimal state.

[Effect]

When the frequency of access to a program increases, the main memory capacity allocated to the program is increased, and when the frequency of access to the file buffer increases, the main memory capacity allocated to the file buffer is increased, so depending on changes in either load. It is possible to dynamically allocate main memory capacity, thereby improving performance.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of this embodiment, in which 1 is a program that measures the load on virtual memory (virtual memory area for programs and their work areas) and file buffers, and 2 is an output from program 1. 3 is a program that controls allocation of main memory to virtual memory and file buffers based on load information;
A program that allocates and deallocates main memory based on decisions made by

4 is a main memory divided into pages.

In FIG. 1, a program 1 for measuring loads on virtual memory and file buffers is called when paging or file input/output requests occur, and collects load information such as the number of page faults and file buffer hit rates.

The program 2 that controls the allocation of main memory is called at regular intervals or when paging occurs.
Based on the load information obtained by the program 1, the allocation of main memory to virtual memory and file buffers is adjusted. According to the simplest algorithm example for adjustment shown in Figure 2, if the load on virtual memory is thought to be heavier than the load on file buffers, such as when the number of paging is large, the amount of main memory allocated to virtual memory increase. Conversely, if the hit rate of the file buffer is low and paging does not occur much, the amount of main memory allocated to the file buffer is increased, and if deemed appropriate, the allocation is left as is.

Examples of other algorithms for allocation are listed below.

The main memory capacity allocated to the file buffer is B (MAX
) and the following equation.

B (MAX)=B (MAX)+F (p) F here
(P) is a function of the number P of 170 pages in a certain period of time, and a simple example is as follows.

F (P) = - Δ: Page ■ / ○ number of times + △: Page I / ○ number of times Program 3 that performs main memory allocation control is an extension of memory allocation requests from other programs, file access, paging, etc. It is called and performs main memory allocation changes, page outs, file buffer release, etc. so as to match the main memory 4 allocation determined by the program 2.

〔Effect of the invention〕

According to the present invention, the allocation distribution of main memory can be dynamically changed according to the load status of the system, so it is possible to improve the usage efficiency of main memory and always obtain stable and good performance. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a flowchart of processing in the embodiment, and FIG. 3 is a diagram showing a conventional main memory management system. 1... A program that measures the load on virtual memory and file buffers, 2... A program that determines main memory allocation, 3.
...Program that controls allocation of main memory, 4...Main memory. 1st B

Claims (1)

[Claims] 1. In a computer system equipped with a virtual memory control function and a function of using part of the main memory as a buffer area to improve access performance for files on an external storage device, the main memory capacity for storing programs and A computer system, characterized in that the allocation distribution of the main memory capacity used for the file buffer is dynamically controlled according to the load of the computer system.