JPS6145344A - Swapping control system - Google Patents

Abstract

PURPOSE:To omit the undesired swapping actions by counting the waiting time for each session and inhibiting the swapping-out action of the relevant session in case the counted waiting time is smaller than the set threshold value. CONSTITUTION:A swapping control system comprises a swapping control table 1, a session number register 2, a timer 3, a subtractor circuit 4, a comparator 4, a transaction control part 7 and a swapping execution control part 8. The part 7 receives the information on the start and end events of a transaction of each session and counts the waiting time of each session to compare the waiting time with the threshold value. Thus the part 7 decides whether or not a swapping action should be carried out in a swapping-out start mode when a transaction is over. The part 8 performs both swapping-in and swapping-out actions with the commands given from the part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a swapping control method for terminal sessions in a time sharing system.

(Prior Art) In a time sharing system (hereinafter referred to as TSS), processing typically proceeds as follows. That is, a user inputs a command or data from a terminal and sends it to the processor at the center. The processor at the center processes the transmitted command or data and transmits the results to the terminal.

The process in which the terminal user looks at the results displayed on the terminal, thinks about the commands and data to input next, and inputs them from the keyboard is reversed.Here, the commands and data are input to the center processor and processed. The process up to outputting the results to the terminal is called a transaction.

Further, the time between transactions, that is, the time spent waiting for input from the terminal is called wait time. Furthermore, the substance of transaction execution at - terminals is called a session. This has implications for jobs in batch systems.

Regarding one session, as mentioned above, it usually takes several tens of seconds for the terminal user to look at the display results from the center processor to the terminal, think about the next data or command to input, and input it from the keyboard. While ordering takes time, processing by the center's processor for commands entered from the terminal is usually completed within a few seconds.
The result is output to the terminal and waits for input from the next terminal. Therefore, from the point of view of the center processor, most of the time for 7 seconds is thought time by the terminal user and time for input from the keyboard, that is, wait time, and during this time,
Since having a 7:1 program in the main memory of a processor wastes the resources of the computer system, a technique called swapping is generally used.

This is when the processor completes processing, displays the result on the terminal, and waits for the next input (hereinafter referred to as the terminal input wait state) (hereinafter referred to as the end of the transaction). When the input from the terminal user is completed and the processor can process it (hereinafter referred to as the start of a transaction) This means that you only need to allocate main memory to the main memory for a session's program if it requires processing by the processor.The number of terminals that can be simultaneously allocated to main memory (for each session) is also large. It is possible to support both at the same time.

In this way, by swapping in at the start of a transaction and swapping out at the end of the transaction, main memory is used efficiently.
Supporting multiple terminals is common practice in Ta2.

However, if you are using a normal terminal that inputs input from a keyboard, thinking and subsequent input using the keyboard are required from the end of the transaction to the start of the transaction, so it is necessary to input from the keyboard after the session is swapped out and then swapped in again. In general, there is sufficient time to execute other sessions, but when data is continuously input to the center from a 70-pin disk on the terminal side, for example, the processor Since the time from when an input request is issued (transaction end) to when data is actually received from the terminal (transaction start) is very short, in conventional swapping control methods, it is difficult to swap out at the end of a transaction. Immediately, swap-in is required again, which not only does not create free space in the main memory, but also increases the usage rate of the secondary storage disk, which is a factor that reduces the throughput of the entire system.

(Objective of the Invention) The present invention measures the waiting time from the end of a transaction to the start of a transaction for each session, and if the measured time is smaller than a set threshold, the waiting time of a subsequent transaction is By assuming that the waiting time is short and not issuing a swap-out request for this session, unnecessary swapping is omitted and swapping overhead is reduced when continuous data is input from the terminal. It was designed to let you do so.

Therefore, the first object of the present invention is to improve the continuous input speed by omitting unnecessary swapping in continuous input, and the second object of the present invention is to reduce the overhead of swapping, thereby enabling high throughput as a whole for the jllT8s. It is also possible to provide a swapping control method.

(Structure of the Invention) The method of the present invention is a swapping control method for a time sharing system that waits for an input from a terminal, and swaps out and swaps in a session corresponding to the terminal in response to an input from the terminal. Wait time measuring means for measuring a wait time from the end of a preceding first transaction in a session to the start of a second transaction following the first transaction; Comparing means for comparing and holding results; and swap-out prohibiting means for prohibiting swapping at the end of the second transaction when the comparison result of the comparing means is smaller than the predetermined value. It consists of:

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

FIG. 1 is a block diagram showing one embodiment of the present invention. The swapping control system shown in FIG. 1 includes a swapping control table 1, a session number register 2, a timer 3, a subtraction circuit 4, and a comparison circuit 5.

a threshold register 6, a transaction control unit 7,
A swapping control table 1 consisting of a swapping execution control section 8 is used to control whether or not swapping is to be performed for each session.

This table has one entry for each session, and each entry L has a time field XTIME for storing the time when the previous transaction ended, and a flag field F for indicating whether swap-out is to be performed for this session. This swapping control table 1 is addressed by the session number j where the transaction start/end occurs, and this address is held in the session number register 2.

The value of the timer 3, which holds the current time, is applied to one input of the subtraction circuit 4, and is also applied to the time field XTIMEK4 of the swapping control table 1. Similarly, the output of the time field XTIME is sent to the subtraction circuit 4.
This output is applied to one input of the comparison circuit 5.

The threshold register 6 is a register that holds a wait time threshold, and its output is applied to the other input of the comparison circuit 5. The input of the comparator circuit 5 is applied to the playing card controller 7.

The transaction control unit 7 notifies events of start and end of transactions in each session.
The Xt transfer is a control unit that measures the wait time in each session and compares it with a threshold value to determine whether or not to perform swap-in at the start of swap-out at the end of the transaction. be.

Swapping execution control unit 8 is transaction control unit 7
Actual swap-in according to instructions from

This is a control unit for performing swap out.

FIG. 2 is an operational flowchart of FIG. 1.

FIG. 2 (ta) shows the operation at the start of a transaction, and FIG. 2 (bl) shows the operation at the end of the transaction.

Next, the operation of the non-embodiment will be explained with reference to FIGS. 1 and 2.

When the terminal input is completed in session j and the processor is ready for processing, that is, when the transaction starts, this notification X is sent.

is applied to the transaction control unit 7, and at the same time, a session signal j is applied to the session number register 2. The transaction control unit 7 receives this notification and performs the following processing. That is, first, the session number jt is stored in the session number register 2, and then the entry corresponding to the session number j in the swapping control table 1 and the timer 3 are read out. The value of the time field X-1-Konmij and the value of the timer 3 read at this time are applied to the subtraction circuit 4, and the result is applied to the comparison circuit 5. This comparison circuit 5 compares the value with the value of the threshold value register 6. Note that the value of the flag field Fj is temporarily saved (the save location is not shown). When the comparison result is that the threshold value is larger,
That is, if the wait time from the end to the start of a transaction is shorter than the threshold, session j in the swapping control table 1 is set to indicate that swap out should be prohibited at the end of the next transaction.
Set the flag field FjK "l' corresponding to the flag field FjK. Otherwise, set the value ""0".

After this, the value of the previously read hook field Fj is checked, and if it is @0, that is, a swap out has been performed at the end of the previous transaction, this session is swapped in.

This swap-in is performed by issuing a command to the swapping execution control section 8. If the value of the previously read 72 field Fj is @1'', that is, if swap-out has not been performed, swap-in is not necessary, and the processing for transaction control ends.

At the end of the transaction, the transaction end notification is sent as at the beginning. is applied to the transaction control unit 7, the session number j is set in the session number register 2, and then the value of the timer 3 is read out and is stored in the corresponding time field XTIMEj of the swapping control table 1.
Store in.

Thereafter, the value of the flag field Fj is read and if it is "1", that is, if the previous wait time is smaller than the threshold value, the transaction control process is ended without swapping out.

If the value of Fj is @0'', the corresponding session is swapped out.

In the description of this embodiment, in order to simplify the explanation, descriptions of parts that are not directly related to the gist of the present invention will be omitted. Furthermore, detailed explanations of how to implement the transaction control unit or swapping control unit are omitted, but they can be implemented using conventionally known methods.

Furthermore, it is clear that the present invention is not limited to the configuration of this embodiment; for example, the session number register 2, threshold value register 6, etc. do not necessarily require special hardware to be prepared as registers; It is also possible to have a storage area above. Subtraction circuit 4. The same applies to the comparator circuit 5, etc., and it is clear that it is not necessarily necessary to provide dedicated hardware for controlling the above-mentioned swapping.

(Effects of the Invention) The present invention improves the continuous input speed by measuring the wait time for each session and prohibiting the session from being swapped out if the wait time is smaller than a set threshold. Moreover, there is an effect that the overhead of swapping is reduced and the throughput of the TSS can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 (
1A and 2B are flowcharts showing the operation of FIG. 1. 1... Swapping control table, 2... Session number register, 3... Timer, 4... Subtraction circuit, 5...
. . Comparison circuit, 6. Threshold register, 7. Transaction control unit, 8. Swapping execution control unit. E 1 Figure j Figure 2

Claims (1)

[Claims] In a swapping control method for a time-sharing system that waits for an input from a terminal, swaps out and swaps in a session corresponding to the terminal in response to an input from the terminal, etc. Wait time measuring means for measuring a wait time from the end of one transaction to the start of a second transaction following the first transaction, and comparing the measured wait time with a predetermined value and retaining the result. and swap-out prohibition means for prohibiting swap-out at the end of the second transaction when the comparison result of the comparison means indicates that the measured wait time is smaller than the predetermined value. Swapping control method.