JPH0451341A - Buffer number managing system - Google Patents

Abstract

PURPOSE:To inform the optimum number of buffers to a user by setting (n-m)(n>=m) buffers without having real areas on a main memory device other than (m) real buffers on the main memory device. CONSTITUTION:A buffer managing means 14 performs buffer control at every issuance of a request to use a page and also, checks whether or not requested page identifiers L1-Ln exist in a buffer page table (BT) 12, and adds one on a hit counter(BC) Cn with a number in accordance with a position where the request page identifiers L1-Ln exist when they exist, and on a BCCn+1 when no request page identifiers exist on a hit number table(HT) 13, respectively. The BT 12 and the HT 13 are comprised of (m) real buffers and (n-m)(n>=m) virtual buffers. A hit rate informing means 15 finds the buffer hit rates of the number of requests to use the BCC1-Ci and that of request to use BCC1-Cn+1 from the HT 13, and informs the optimum number of buffers to the user.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a buffer number management method, and particularly to buffer number management in an information processing system that manages the number of buffers in a main memory device used for input/output of pages in an auxiliary storage device. Regarding the method.

[Conventional technology]

In conventional buffer number management methods, in order to find the optimal number of buffers in the main memory used for input/output of pages in the auxiliary storage, the target process is executed with the number of buffers changed several times, or The optimal number of buffers was determined by considering the physical structure of each file stored in the auxiliary storage device and predicting the page input/output for each file.

[Problems to be solved by the invention] ゛The conventional buffer number management method described above may not be able to obtain the optimal number of buffers unless the target process is executed by changing the number of buffers many times, or If the structure is not known, the optimum number of buffers cannot be predicted, and it has the disadvantage that it takes a lot of effort to obtain the optimum number of buffers for the main memory.

The purpose of the present invention is to set n-m virtual buffers (where n≧m) that do not have a real area on the main memory in addition to m real buffers on the main memory. With this method, the buffer hit rate for the number of buffers from 1 to n can be obtained in one execution of the target process, and the buffer hit rate can be notified to the user as information for determining the optimal number of buffers. The goal is to provide a method.

[Means to solve the problem]

The buffer number management method of the first invention rewrites a new page that is not in the buffer of the main memory read from the auxiliary memory in response to a usage request onto the buffer of the main memory that has the page that was used at the oldest point in time. In an information processing system that performs buffer control for storing pages in the auxiliary storage device, in a buffer number management method that manages the number of buffers in the main storage device used for inputting and outputting pages in the auxiliary storage device, (A)
m real buffers in operation on the main memory) (B) identifiers of m pages in operation in each of the real buffers and priority of use over the real buffers in addition to the real buffers; Assuming that there are n-m virtual buffers with a low value (where n≧m), the most recent point in time with respect to n-m page identifiers assumed during operation on the virtual bar/sofa. (C) n hit counters each having the number of usage requests for pages corresponding to each number in the buffer page table; (D) A hit count table that has an n+1 hit counter that has the number of usage requests for pages that are not in any of the buffers; Check whether the identifier exists in the buffer page table;
buffer management means that adds 1 to a hit counter corresponding to a position where the requested page identifier exists on the hit count table; when the requested page identifier does not exist, adds 1 to the (n+1)th hit counter; ) For a certain number of buffers i (where n≧i), using the contents of the hit count table, calculate the value obtained by adding the i number of usage requests in the first to i-th hit counters, and 1. Hit rate notification means for calculating the ratio of the number of usage requests added to the number of n+1 usage requests in the number of hit counters from the number n+1 to the number n+1, and notifying the user as information for determining the optimal number of buffers. It is configured.

In addition, the buffer number management method of the second invention stores a new page read from the auxiliary storage device in response to a usage request and which is not in the buffer of the main storage device, onto the buffer of the main storage device that has the page that was used at the oldest point in time. In an information processing system that performs buffer control for rewriting and storing pages in the auxiliary storage device, in a buffer number management method that manages the number of buffers in the main storage device used for inputting and outputting pages in the auxiliary storage device, (A) , identifiers of m active pages in each of the m real buffers active on the main memory, and n−m pages whose use priority is lower than that of the real buffer in addition to the real buffer. Assuming that there is a virtual buffer (where n≧m), numbers are assigned in order from the most recently used page for the n-m page identifiers assumed during operation in the virtual buffer. (B) in the hit count table, n hit counters having the number of usage requests for pages corresponding to each number in the buffer page table, and in neither the real buffer nor the virtual buffer; (C) each time there is a request to use a page, it is checked whether the identifier of the requested page exists in the buffer page table; If the requested page identifier exists on the hit count table, add 1 to the hit counter with the number corresponding to the position where the requested page identifier is located, and if it does not exist, add 1 to the n+1th hit counter, respectively, For i (where n≧i), using the contents of the hit count table, add the i number of usage requests in the 1st to ith hit counters, and the 1st to n+1th hit counters. By determining the ratio between the number of usage requests and the number of usage requests (n+1) in the hit counter up to that point, the user is notified as information for determining the optimal number of buffers.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the buffer number management method of the present invention.

The information processing system of this embodiment rewrites and stores a new page that is not in the buffer of the main storage device read from the auxiliary storage device in response to a usage request on the buffer of the main storage device that has the page that was used at the oldest point in time. Performs buffer control.

As shown in FIG. 1, the buffer area 11 consists of m real buffers B
＋・・・・・・BI, ゛.

In addition, the buffer page table 12 includes the real buffer Bl
Identifiers of m pages operating in each of +...B, Lt+L2t...L,..., and real buffer BI+...B, priority of use Assuming that there are n-m virtual buffers (n≧m) with low
−m page identifiers LyH+I!・・・・・・L、
, are given numbers in order from the most recently used page, and the identifiers of n pages L'l+L2+
・・・・・・L, , is held.

On the other hand, the hit number table 13 includes numbers 1, 2, . ...Number of usage requests for the page corresponding to n Ct + C2+ ...
・It has n hit counters with Cn and an n+1 hit counter with the number of usage requests for pages that are not in any of the m real buffers and nm virtual buffers, 0□1. .

Therefore, the buffer management means 14 performs buffer control every time there is a request for use of a page, checks whether the identifier of the requested page exists in the buffer page table 12, and writes it on the hit number table 13.
When the requested page identifier exists, 1 is added to the hit counter corresponding to the position where the requested page identifier exists, and when it does not exist, 1 is added to the n+1th hit counter.

FIG. 2 is a flowchart showing an example of the operation of the buffer management means 14 of this embodiment.

The buffer management means 14 in FIG. 2 first begins in step S1.
Then, a search is made to see if the identifier of the requested page exists in the buffer page table 12.

Then, in step S2, if the requested page identifier exists in the buffer page table 12, 1 is added to the hit counter on the hit count table 13 corresponding to the position of the requested page identifier, and If the identifier of the page that has been updated does not exist in the buffer page table 12, n+1 on the hit count table 13
The hit number table 13 is updated by adding 1 to the th hit counter.

In addition, in step S3, the stored contents of the buffer page table 12 up to the position before the position where the requested page identifier is located are shifted backward one by one, and the requested page identifier is placed at the beginning of the buffer page table 12. I remember.

Next, in step S4, it is determined whether the requested page is a real buffer in the buffer area 11.

If it is a real buffer (YES), the process moves to step S7, and if it is not a real buffer (NO), a real buffer containing the oldest used page is searched for in step S5.

Then, in step S6, it is checked whether there is an update flag at the position of the buffer page table 12 corresponding to the real buffer containing the page used at the oldest point, and if there is an update flag, the page is used at the oldest point. The requested page is input after the requested page is output to the auxiliary storage device.

Next, in step S7, it is determined whether the request is an update request or an input request.

Then, only if it is an update request, in step S8,
An update flag is set at the top position of the buffer page table 12 that has the identifier of the requested page.

Furthermore, the hit rate notification means 15 sends a certain number of buffers i(
However, for n≧i), hit count table 1
Using the contents of 3, the value Ct +C2+ is the sum of the number of i usage requests in the hit counters from 1st to 1st.
......+CI and the number of n+1 usage requests in the 1st to n+1st hit counters C
t+C2+...10 The ratio with n+1 is defined as the buffer hit rate HI, and the following is calculated and notified as information for the user to determine the optimal number of buffers.

Therefore, the user can easily determine the number of buffers in the main memory used for inputting and outputting pages in the auxiliary memory.

Next, an example of state changes for the buffer page table and the hit count table will be described in the case where m is 3 and n is 6 in this embodiment.

Figure 3 shows this example where m is 3 and n is 6, and the identifier 12
FIG. 3 is a block diagram showing an example of the state of a buffer page table and a hit count table immediately before a page is requested to be used. Further, FIG. 4 is a block diagram showing an example of the state of the buffer page table and the number of hits table immediately after the usage of 12 identifiers is requested in this embodiment where m is 3 and n is 6. .

As shown in FIG. 8, the buffer page table 12 is
Page identifier =I L L2=8°L3=4. L
4 = 6. L! ,=12. LB = 13, and the hit count table 13 sets the number of usage requests in the hit counter to Cs = 1. C2=2- Ca=3, C422. C,
,=7. C3=7. With C7=9, 12 pages of identifiers are requested.

Therefore, as shown in FIG. 4, the page with the identifier 12 is the most recently used page, so that identifier is at the top position, and the buffer page table 12 is as follows:
Page identifier Ls=12, L2=IL L3=8.
L4=4. L, = 6, L8 = 13, and since the request was for the page with the identifier located at the fifth position in the battle page table 12, the hit number table 13 shows the usage request at the fifth hit counter. By adding 1 to the number of requests 05, the number changes to C15=8.

In the state shown in FIG. 4, the buffer hit rate H5 when the number of buffers is 5 is as follows, which is 50%.

〔Effect of the invention〕

As explained above, in addition to m real buffers on the main memory, the buffer and account management system of the present invention has n-m real buffers that do not have real areas on the main memory (where n≧ In order to determine the optimal number of buffers for the user by setting virtual buffers (m), the buffer hit rate for the number of buffers from 1 to n is obtained in one execution of the target process. This has the effect that it can be notified as information.

As a result, the buffer number management method of the present invention helps the user determine the optimal number of buffers, and has the effect that the user can easily and efficiently process the target with the optimal number of buffers. have.

~C□,C□,...Number of usage requests, L 11 L
2 +~L,...Identifier.

Claims (1)

[Claims] 1. A new page read from the auxiliary storage in response to a usage request and not in the buffer of the main storage is rewritten and stored on the buffer of the main storage that has the page used at the oldest time. In an information processing system that performs buffer control, in a buffer number management method that manages the number of buffers in the main storage device used for input/output of pages in the auxiliary storage device, (A) a buffer that is in an operating state on the main storage device; m real buffers; (B) the identifiers of the m pages operating in each of the real buffers, and the identifiers of the m pages in operation in each of the real buffers; Assuming that there is a virtual buffer (n≧m), numbers are assigned in order from the most recently used page to the identifiers of n-m pages assumed during operation in the virtual buffer. (C) n hit counters having the number of use requests for pages corresponding to each number in the buffer page table, and the number of use requests for pages that are not in either the real buffer or the virtual buffer; (D) Performs buffer control each time there is a request to use a page, and checks whether the identifier of the requested page exists in the buffer page table. buffer management means that adds 1 to a hit counter corresponding to a position where the requested page identifier exists on the hit number table, and to an (n+1)th hit counter when the requested page identifier does not exist; (E) For a certain number of buffers i (where n≧1), using the contents of the hit count table, calculate the value obtained by adding the i number of usage requests in the first to i-th hit counters. , a hit rate notification means for determining the ratio between the number of usage requests of n+1 in the first to n+1 hit counters and notifying the user as information for determining the optimal number of buffers; A buffer number management method characterized by comprising: 2. Information processing that performs buffer control to rewrite and store a new page read from the auxiliary storage device in response to a use request and not in the buffer of the main storage device on the buffer of the main storage device that has the page that was used at the oldest point in time. In the system, in a buffer number management method for managing the number of buffers in the main memory used for input/output of pages in the auxiliary storage, (A) a buffer page table indicates that the number of buffers in the main memory is in an operating state; Identifiers of m pages operating in each of m real buffers, and in addition to the real buffers, n-m virtual pages whose usage priority is lower than that of the real buffers (where n≧m) Assuming that there is a buffer, the identifiers of nm pages assumed during operation in the virtual buffer are assigned numbers in order from the page used most recently, and (B) hit number table. , n hit counters having the number of use requests for pages corresponding to each number in the buffer page table, and n hit counters having the number of use requests for pages that are not in either the real buffer or the virtual buffer.
(C) Every time there is a request for use of a page, it is checked whether the requested page identifier exists in the buffer page table, and if the identifier of the requested page exists on the hit count table, When the requested page identifier does not exist, add 1 to the hit counter number corresponding to the position where the requested page identifier exists, and add 1 to the n+1th hit counter when the requested page identifier does not exist. ), using the contents of the hit count table, add the i number of usage requests in the 1st to i-th hit counters, and n+1 in the 1st to n+1th hit counters. A method for managing the number of buffers characterized in that information for determining the optimum number of buffers is notified to the user by determining the ratio between the number of usage requests and the sum of the number of usage requests.