JP2001109664A - Information processor and buffer managing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a buffer list control method capable of improving a hit rate and accelerating the average speed of access to stored data. SOLUTION: Concerning the buffer managing method for accessing data inside a secondary storage device after storing them in a buffer, the number of times of access after storing respective data in the buffer is stored for each piece of data, plural pointers are prepared for inserting buffer information in the middle of a buffer list having the list of respective pieces of buffer information showing respective buffers, and when data are read out in the buffer at the time of requesting the acquisition of the data, the number of times of access corresponding to the relevant data is acquired. When that number of times of access is more than the prescribed number of times, the buffer information showing the said buffer is moved from a position on the buffer list corresponding to the kind of the relevant data to a position closer to the end, but when it is less than the prescribed number of times, this buffer information is moved to a position corresponding to the kind of the data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buffer list control method for controlling a buffer list such as an LRU list for managing a buffer for temporarily storing data in a secondary storage device in a main storage device. The present invention relates to a buffer list control method capable of improving the average access speed to stored data by increasing the probability that such data exists in a buffer.

[0002]

2. Description of the Related Art Generally, an information processing apparatus has a high access speed (short access time) but a small storage capacity of a main storage device (for example, a RAM or the like). A large secondary storage device (auxiliary storage device, for example, a hard disk device). Therefore, in the information processing apparatus having such a configuration,
In order to improve the average access speed to data stored in the main storage device or the secondary storage device, data that is likely to be accessed frequently is stored in the main storage device. As one of such conventional techniques, in recent years, L
A buffer list control technique called RU (Least Recently Used), which has the meaning of least recently used, is provided. In this LRU list control, a plurality of buffers constituting a main storage device are provided, and An LRU list including individual buffer information (for example, pointer information to a buffer or a buffer number) associated with each buffer or the buffer itself is configured in the main storage device, and indicates a buffer that has been used least recently. The buffer information or buffer is, for example, the LR
If the data to be accessed is not in the LRU list at the time of data access, the data is read from the secondary storage device, and is displayed in the first buffer or at the top of the LRU list. Stored in the buffer that has been set. As a result, the data stored in the buffer at the head position is lost.
That is, the data is stored only in the secondary storage device. The buffer information or the buffer indicating the buffer storing the new data is moved from the head on the LRU list to the end of the LRU list, and the buffer is accessed in this state. On the other hand, at the time of data access, if the data to be accessed is in the LRU list, buffer information indicating the buffer in which the data is stored or the buffer from the current position on the LRU list to the end of the LRU list And in that state, access the buffer. In this way, of the data stored in the buffer, if the access to the data does not occur after the buffer is moved to the end of the LRU list, the buffer information or the buffer indicating the buffer is eventually stored in the LRU list. Reach the beginning. In the LRU list control disclosed in JP-A-6-52060, a plurality of pointers pointing to the middle of the LRU list are prepared, and when data is accessed, a buffer for storing the data is not moved to the end of the LRU list. Is moved to the position indicated by the pointer selected according to the type of data.
In other words, in this LRU list control, the buffer in which the type of data that is likely to be accessed frequently is stored in, for example, L
This means that the data is stored far away from the head of the RU list in the buffer for a longer time.

[0003]

SUMMARY OF THE INVENTION
In the prior art described in 6-52060,
If a certain type of data is regarded as having a high access frequency and, as a result, is treated as having a high priority, data belonging to that type is accessed once and then lower even if it is not accessed at all. As long as a part of the data belonging to the type of the priority is being accessed and the buffer information or the buffer indicating the buffer storing the data belonging to the type is in the LRU list, it is not replaced. As a result, there is a problem that the use efficiency of the buffer is reduced, and the hit ratio (probability of being stored in the buffer) of frequently accessed data is reduced. An object of the present invention is to solve such a problem of the prior art, and to provide a buffer for a longer period of time for a type of data having a higher access frequency, and to provide a buffer for a longer period even for a type of data having a high access frequency. It is an object of the present invention to provide a buffer list control method capable of increasing a hit rate by releasing a buffer when there is no access and improving an average access speed to stored data.

[0004]

In order to solve the above-mentioned problems, according to the present invention, data in a secondary storage device is temporarily stored in a buffer in a main storage device before accessing the data. In the information processing apparatus, a buffer list control unit that controls a list of individual buffer information indicating individual buffers or a buffer list having a list in which the individual buffers are incorporated, and stores individual data in the buffers And an access number storage means for storing the number of accesses from each of the data, and having a plurality of pointers for inserting buffer information or one of the buffers in the middle of the buffer list. The buffer list control means accesses the access number associated with the data from the access count storage means. A buffer for storing the data at a position on the buffer list pointed to by the selected pointer, and selecting one of the pointers according to the obtained access frequency and the type of the data. The buffer information is inserted. Also,
According to the second aspect of the present invention, in the information processing apparatus for temporarily storing data in a secondary storage device in a buffer in a main storage device and then accessing the data, a list of individual buffer information indicating each buffer or Buffer list control means for controlling a buffer list having a list in which the buffer itself is incorporated, and a configuration having a plurality of pointers for inserting buffer information or one of the buffers themselves in the middle of the buffer list; At the time of access, the buffer list control means checks whether or not the access to the data is the first access after storing the data in the buffer, and the pointer according to the check result and the type of the data. One of the data points, and moves the data to the position on the buffer list pointed to by the selected pointer. And the configuration of inserting a buffer or buffer information that stores. According to a third aspect of the present invention, in the buffer management method of the information processing apparatus for temporarily storing data in the secondary storage device in a buffer in the main storage device and then accessing the data, the individual When controlling a buffer information list or a buffer list having a list in which each buffer itself is incorporated, the number of accesses after storing each data in the buffer is stored for each of the data, and the buffer A buffer information or a plurality of pointers for inserting one of the buffers is prepared in the middle of the list, and at the time of data access, the number of accesses associated with the data is obtained, and the obtained access number and the data Select one of the pointers according to the type of the pointer, and select a buffer list indicated by the selected pointer. To the position and the method of inserting the buffer or buffer information that stores the corresponding data.

According to the invention described in claim 4, according to claim 3,
In the described invention, if the access to the data is the first access after storing the data in the buffer, select a pointer associated with the type of the data, if not the first access, In accordance with the number of accesses, the pointer or a pointer located farther from the buffer return position than the pointer is selected. According to a fifth aspect of the present invention, in the buffer management method of the information processing apparatus for temporarily storing data in the secondary storage device in a buffer in the main storage device and then accessing the data, the individual When controlling a buffer information list or a buffer list having a list in which the buffer itself is incorporated, a plurality of pointers for inserting buffer information or one of the buffers themselves are prepared in the buffer list. At the time of data access, whether or not the access to the data is the first access after storing the data in the buffer is checked, and one of the pointers is determined according to the check result and the type of the data. A buffer for storing the data at a position on the buffer list pointed to by the selected pointer or a buffer thereof. It was how to insert the file information. In the invention according to claim 6, in the invention according to claim 5, if the access to the data is the first access after storing the data in the buffer, the data is associated with the type of the data. If the pointer is not the first access, a pointer farther from the buffer return position than the pointer is selected. According to the first and third aspects of the present invention, a buffer list having a list of individual buffer information indicating individual buffers or a list in which each buffer itself is incorporated is controlled. In this case, the number of accesses from storing individual data in the buffer is stored for each data, and a plurality of pointers for inserting buffer information or one of buffers in the buffer list are prepared. In addition, at the time of data access, the number of accesses stored in association with the data is acquired, and one of the pointers is selected according to the acquired number of accesses and the type of the data, and the selected pointer is selected. The buffer for storing the data or its buffer information is inserted into the position on the buffer list indicated by.

According to a fourth aspect of the present invention, in the third aspect of the invention, if the access to the data is the first access after storing the data in the buffer, the data is associated with the type of the data. The selected pointer is selected, and if it is not the first access, the pointer or a pointer farther from the buffer return position than the pointer is selected according to the number of accesses. According to the second and fifth aspects of the present invention, when controlling a buffer list having a list of individual buffer information indicating individual buffers or a list in which the buffer itself is incorporated, buffer information or buffer information is provided in the middle of the buffer list. A plurality of pointers for inserting one of the buffers themselves is prepared, and at the time of data access, it is checked whether the access to the data is the first access after storing the data in the buffer, One of the pointers is selected according to the result of the check and the type of the data, and a buffer for storing the data or its buffer information is inserted into a position on the buffer list pointed to by the selected pointer. . In the invention according to claim 6, in the invention according to claim 5, if the access to the data is the first access after storing the data in the buffer, the pointer associated with the type of the data Is selected, and if it is not the first access, a pointer at a position farther from the buffer return position than the pointer is selected.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration block diagram of a main part of an information processing apparatus according to each embodiment of the present invention. As shown in the figure, an information processing apparatus according to this embodiment includes a main storage device 1 constituted by a RAM or the like, a CPU 2 for controlling the entire information processing device according to a program loaded into the main storage device 1, various data and programs. A secondary storage device (auxiliary storage device, for example, a hard disk device) 3 in which the information is stored is provided. The main storage device 1 includes a plurality of buffers (not shown) for temporarily storing data in the secondary storage device 3 and a list of individual buffer information associated with each buffer. An LRU list 4 is provided as a buffer list having the following. The LRU list 4 is also an access count storage unit for storing the access count for each data in each buffer. In addition, the main storage device 1 storing the program and C
The PU2 operates as a buffer list control unit that controls the LRU list, and the buffer list control unit obtains the number of accesses associated with the data from the number-of-accesses storage unit at the time of data access, and obtains the obtained access One of a plurality of pointers (pointing to a plurality of positions in the LRU list) is selected according to the number of times and the type of the data, and the LRU indicated by the selected pointer is selected.
The buffer information indicating the buffer for storing the data is inserted into the position on the list. With such a configuration,
In this embodiment, when the user requests data in the secondary storage device 3, the CPU 2 refers to the LRU list to determine whether or not the data has been read into the buffer.
For example, if the data has not been read, the data is read from the secondary storage device 3, stored in a buffer managed using the LRU list 4, and the buffer is accessed.

FIG. 2 shows an operation flow of the first embodiment of the present invention. Hereinafter, the operation of this embodiment will be described in detail with reference to FIG. In this embodiment, first, at the time of data access (at the time of data reading), for example, a user or an application program issues a data acquisition request with a target data name (eg, file name) and data type (step S1). ). Then, the CPU 2 refers to the LRU list 4 and determines whether or not the data (the data of the data name) has been read from the secondary storage device 3 to the buffer in the main storage device 1 (Step S2). FIG. 3 shows the state of the LRU list 4 at this time. As shown in the figure, the LRU list 4 is composed of a plurality of connected individual information strings, and one set of individual information includes information indicating the type of data such as A, B, and C and a data name (shown in the figure). No), the number of accesses since the data was stored in the buffer (information indicated by numerical values such as 421,999), and pointers as buffer information indicating each buffer (indicated as B11, B12, B13, B14, and B15) It is composed of With such a configuration, in the illustrated example, as the individual information corresponding to the first buffer, the data type A (data name is omitted), the number of accesses 421 times after storing the data in the buffer, the pointer B
11 is stored, the next is stored as type A, 999 accesses, pointer B12, the next is stored as type B, 30 accesses, pointer B13, and the next is type C, 1 access, pointer B14. It is memorized, the next is type C, the number of access times is 2,
The pointer B15 is stored. In addition, the type of data is, for example, a file constituting a homepage,
HTML files, image files, movie files,
If the page is a sound file or the like and constitutes a file having a tree structure, the page includes a header page, a root page representing a root of a tree, a node page representing a node of a tree, and a leaf page representing a leaf of a tree. The head pointer P10 shown in FIG. 3 indicates the individual information at the head (buffer acquisition / return position) of the LRU list.
1, P12 and P13 indicate the middle of the LRU list corresponding to the data type.

In the example of FIG. 3, when the buffer storing the data to be accessed does not exist in the LRU list 4 (No in step S2), the CPU 2 stores the data in the buffer pointed to by the pointer B11 stored at the head of the LRU list 4. (Target data) is read from the secondary storage device 3 (step S3). If the type of the data is, for example, B, as shown in FIG. 4, the individual information including the buffer information (pointer) is moved from the head of the LRU list 4 to the position indicated by the pointer P12 corresponding to the type B of the data. (Step S
4). Since the first access is made after the data is stored in the buffer, the number of accesses is set to 1 as shown (step S5), and the access to the buffer is performed (step S6). On the other hand, if the buffer storing the data to be accessed is in the LRU list 4 (Yes in step S2), the number of accesses to the data is compared with a predetermined number A (step S7). (Yes in step S7), the individual information including the buffer information is moved to the position indicated by the pointer closer to the end of the LRU list 4 than the pointer corresponding to the data type (step S8), and the number of accesses is increased by 1 (step S9). ), The access to the buffer is performed (step S6). For example, if the predetermined number of times is 500 and the buffer that stores the data in FIG. 4 is the buffer pointed to by the pointer B12, even if the type of the data is A, the number of times that the data is stored in the buffer Is 999
5, the individual information including the buffer information (pointer B12) is moved to the position indicated by the pointer P12 closer to the end of the LRU list 4 than the pointer P11 corresponding to the data type, as shown in FIG. is there. In this way, even if the buffer at the position corresponding to the type of data having a low priority (the position near the head of the LRU list) is accessed as described above, if the frequency of access to the buffer is high, the data of the buffer is accessed. Individual information such as buffer information associated with a buffer storing data of a type having a higher priority than the type is shifted to the previous position. In the above, if the number of accesses to the data is smaller than the predetermined number A (No in step S7), the individual information is moved to the position of the pointer corresponding to the type of the data (step S10), and the number of accesses is reduced. One is increased (step S8), and the access to the buffer is performed (step S6).

In FIG. 4, if the pointer to the buffer for storing the data to be accessed is B12 and the number of accesses after storing the data is equal to or more than a predetermined number B which is larger than the predetermined number A, For example, as shown in FIG. 6, the pointer P1 closer to the end of the LRU list 4
A configuration in which the individual information including the pointer B12 is moved to the position indicated by 3 is also possible. In this case, even when data of type A having a lower priority is accessed, individual information including a pointer of a buffer for storing data of type B having a higher priority and data of a type C having a higher priority is stored in the LRU list 4. Move forward one by one. FIG. 7 is an operation flowchart showing the second embodiment of the present invention. Hereinafter, the operation of this embodiment will be described with reference to FIG. In this embodiment, first,
At the time of data access (at the time of data reading), for example, a user or an application program issues a data acquisition request with a target data name (for example, a file name) and a data type (step S11). Then, the CPU 2 refers to the LRU list 4 and determines whether or not the data (the data of the data name) has been read from the secondary storage device 3 to the buffer in the main storage device 1 (step S12).

FIG. 8 shows the state of the LRU list 4 at this time. As shown in the figure, the LRU list 4 is composed of a plurality of connected individual information strings, and one set of individual information includes information indicating the type of data such as A, B, and C and a data name (shown in the figure). No), and pointers (shown as B21, B22, B23, B24, B25) as buffer information indicating each buffer. FIG.
The pointer P20 shown in (1) indicates the individual information at the head of the LRU list 4, and the plurality of pointers P21, P22, and P23 indicate the middle of the LRU list 4 corresponding to the data type. Unlike the case of the first embodiment, each individual information does not store the number of accesses since the data was stored. In the example of FIG. 8, when the buffer storing the data to be accessed does not exist in the LRU list 4 (N in step S12)
o), the CPU 2 reads the data (target data) from the secondary storage device 3 into the buffer pointed to by the pointer B21 stored at the head of the LRU list 4 (step S13).
Then, if the type of the data is, for example, B, as shown in FIG.
(Step S14), and accesses the buffer pointed by the pointer P22 (step S15).
On the other hand, if the buffer storing the data to be accessed is in the LRU list 4 (Ye in step S12)
s), the individual information including the pointer to the buffer is L
The RU list 4 is moved to the end or a position closer to the end than the position corresponding to the type of data (step S16), and the buffer pointed to by the pointer is accessed (step S15). For example, in FIG. 9, when the pointer of the buffer storing the data to be accessed is B22, since it is not the first access after storing the data in the buffer, the individual information including the pointer B22 is replaced with the type A of the data as shown in FIG. Instead of the pointer P21 corresponding to
Is moved to the end of the LRU list indicated by. Thus,
According to the second embodiment, when data of a type A having a lower priority is accessed, data of a type B having a higher priority and data of a type C having a higher priority as well as the type B are stored. The individual information including the pointer of the buffer to be moved to the previous one on the LRU list 4.

In the above description, the LRU list 4 includes a pointer to a buffer. However, a buffer number or the like may be used as buffer information instead of the pointer, or the buffer itself may be incorporated in the LRU list 4. When the buffer itself is incorporated, LRU is stored in one buffer.
It has a pointer to the next buffer on list 4. Therefore, in such a case, the pointer (for example, P10) pointing to the beginning of the LRU list 4 changes, and
When the data is inserted in the middle of the RU list 4, a pointer to the next buffer is obtained from the buffer at the insertion position, and the pointer is used as a pointer to the next buffer of the inserted buffer. The pointer to the next buffer of the buffer at the insertion position is set as a pointer indicating the insertion position. In the above description, the buffer return position is at the head of the LRU list 4, and every time buffer information or the like is inserted in the middle, the buffer information or the like at the head of the LRU list 4 from that position is at the head. In the reverse direction, the buffer return position is set to the end of the LRU list, and every time buffer information or the like is inserted in the middle, buffer information at the end of the LRU list from that position is returned. Can be advanced by one toward the end.

[0013]

As described above, according to the present invention,
According to the first and third aspects of the invention, when controlling a buffer list having a list of individual buffer information indicating individual buffers or a list in which the individual buffers themselves are incorporated, individual data is stored in the buffers. The number of times of access after that is stored for each of the data, and a plurality of pointers for inserting buffer information or one of buffers are prepared in the middle of the buffer list. The number of accesses stored in association with the data is acquired, one of the pointers is selected according to the acquired number of accesses and the type of the data, and the position on the buffer list pointed to by the selected pointer is acquired. Since the buffer for storing the data or the buffer information is inserted, the type of frequently accessed data is A buffer is given for a longer period of time, and even if the type of data is frequently accessed, if there is no access for a long period of time, the buffer or buffer information of that data will move to the buffer return position and the buffer will be released, so The hit rate is improved, and the average access speed to the stored data is improved. Further, in the invention according to claim 4, in the invention according to claim 3, if the access to the data is the first access after storing the data in the buffer, the data is associated with the type of the data. The pointer according to claim 3, wherein the pointer is selected and if not the first access, the pointer or a pointer farther from the buffer return position than the pointer is selected according to the number of accesses, so that the effect of claim 3 is easily realized. can do. According to the second and fifth aspects of the present invention, when controlling a buffer list having a list of individual buffer information indicating individual buffers or a list in which the buffer itself is incorporated, a buffer is provided in the middle of the buffer list. A plurality of pointers for inserting information or one of the buffers themselves are prepared, and when accessing data, it is checked whether or not the access to the data is the first access after storing the data in the buffer. One of the pointers is selected according to the result of the check and the type of the data, and the buffer for storing the data or its buffer information is inserted into a position on the buffer list pointed to by the selected pointer. Therefore, the same effect as the first or third aspect of the invention can be realized. In the invention according to claim 6, in the invention according to claim 5, if the access to the data is the first access after storing the data in the buffer, the data is associated with the type of the data. If the pointer is selected and the access is not the first access, the pointer at a position farther from the buffer return position than the pointer is selected, so that the effect of claim 5 can be easily realized.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a main part of an information processing apparatus according to each embodiment of the present invention.

FIG. 2 is an operation flowchart of a buffer management method according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a buffer management method according to the first embodiment of the present invention.

FIG. 4 is another explanatory diagram of the buffer management method according to the first embodiment of the present invention.

FIG. 5 is another explanatory diagram of the buffer management method according to the first embodiment of the present invention.

FIG. 6 is another explanatory diagram of the buffer management method according to the first embodiment of the present invention.

FIG. 7 is an operation flowchart of a buffer management method according to a second embodiment of the present invention.

FIG. 8 is an explanatory diagram of a buffer management method according to a second embodiment of the present invention.

FIG. 9 is another explanatory diagram of the buffer management method according to the second embodiment of the present invention.

FIG. 10 is another explanatory diagram of the buffer management method according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main storage device 2 CPU 3 Secondary storage device 4 LRU list

Claims (6)

[Claims] 1. An information processing apparatus for temporarily storing data in a secondary storage device in a buffer in a main storage device and then accessing the data, wherein a list of individual buffer information indicating each buffer or an individual buffer is provided. A buffer list control unit that controls a buffer list having a list incorporated therein, and an access number storage unit that stores the number of accesses from storing individual data in the buffer for each data, The buffer list has a plurality of pointers for inserting buffer information or one of buffers in the middle of the buffer list, and at the time of data access, the buffer list control unit is associated with the data from the access count storage unit. Acquires the number of accesses and responds to the acquired number of accesses and the type of the data. An information processing apparatus, wherein one of the pointers is selected, and a buffer for storing the data or its buffer information is inserted into a position on the buffer list indicated by the selected pointer. 2. An information processing apparatus for temporarily storing data in a secondary storage device in a buffer in a main storage device and then accessing the data, wherein a list of individual buffer information indicating each buffer or the buffer itself is used. A buffer list control means for controlling a buffer list having a built-in list is provided, and a configuration having a plurality of pointers for inserting buffer information or one of the buffers themselves in the middle of the buffer list, at the time of data access, The buffer list control means checks whether or not the access to the data is the first access after storing the data in the buffer. According to the check result and the type of the data, one of the pointers in the pointer is checked. And stores the data at a position on the buffer list pointed to by the selected pointer. An information processing apparatus characterized in that a buffer or buffer information thereof is inserted. 3. A buffer management method for an information processing apparatus in which data in a secondary storage device is temporarily stored in a buffer in a main storage device and then the data is accessed, wherein a list of individual buffer information indicating each buffer is provided. Alternatively, when controlling a buffer list having a list in which each buffer itself is incorporated, the number of accesses after storing each data in the buffer is stored for each of the data, and the buffer is stored in the middle of the buffer list. A plurality of pointers for inserting one of the information or the buffer is prepared, and at the time of data access, the number of accesses associated with the data is obtained, and according to the obtained number of accesses and the type of the data, Select one of the pointers and move the pointer to a position on the buffer list pointed to by the selected pointer. A buffer management method comprising inserting a buffer for storing data or buffer information thereof. 4. The buffer management method according to claim 3, wherein if the access to the data is the first access after storing the data in the buffer, a pointer associated with the type of the data is set. A buffer management method comprising: selecting, if not the first access, the pointer or a pointer at a position farther from the buffer return position than the pointer according to the number of accesses. 5. A buffer management method for an information processing device in which data in a secondary storage device is temporarily stored in a buffer in a main storage device and then the data is accessed, wherein a list of individual buffer information indicating each buffer is provided. Alternatively, when controlling a buffer list having a list in which the buffer itself is incorporated, a plurality of pointers for inserting buffer information or one of the buffers themselves are prepared in the middle of the buffer list, and at the time of data access, Check whether the access to the data is the first access after storing the data in the buffer, select one of the pointers according to the check result and the type of the data, and select The buffer for storing the data or its buffer information is inserted into the buffer list at the position indicated by the pointer. A buffer management method. 6. The buffer management method according to claim 5, wherein if the access to the data is the first access after storing the data in the buffer, a pointer associated with the type of the data is set. And selecting a pointer at a position farther from the buffer return position than the pointer if the access is not the first access.