JP5455111B2 - Flow control device and flow control method - Google Patents

Description

  The present invention relates to a flow control device and a flow control method, and more particularly to a technique for controlling the number of threads, which is a unit of information processing amount to be processed by a computer.

  In general, the term process is used as a unit in which an operating system (OS) processes a program. A process is composed of processing units called one or more threads. From the viewpoint of increasing processing efficiency, it is often performed to multiplex threads for processing. However, if threads are multiplexed so that system resources are used up, the processing efficiency will be worse.

  In order to prevent such excessive multiplexing of threads, a method of dynamically controlling the flow rate of processing threads in accordance with the usage status of system resources has been proposed (see, for example, Patent Document 1). In the technique described in Patent Document 1, a thread basic information table as shown in FIG. 7 of Document 1 is created and stored in advance, and the above thread basic information table is stored in accordance with the CPU usage rate actually measured. The limit multiplicity stored in is dynamically changed.

JP 2007-122527 A

  However, with the technique described in Patent Document 1, it is necessary to create a thread basic information table in advance. The thread basic information table is obtained by storing the design value of the limit multiplicity for each thread. Here, for example, in a large-scale system such as a bank ATM system, hundreds to thousands of application programs are executed simultaneously, and the number of threads is extremely large. Therefore, it takes a lot of labor and time to create the thread basic information table, and there arises a problem that a management load increases. Therefore, it is not realistic to apply the technique of Patent Document 1 to such a large-scale system.

  In the technique of Patent Document 1, if there is a large difference between the design value initially stored in the thread basic information table and the CPU usage rate actually measured, the limit multiplicity is The value of may be changed at once. If the value of the limit multiplicity increases at a stretch, the number of threads activated simultaneously increases at a stretch. If this happens, the threads will be over-multiplexed and the CPU usage rate will rise rapidly, and this time it will be necessary to reduce the CPU usage rate that has risen too much. As described above, when the CPU usage rate is repeatedly increased or decreased, there arises a problem that the processing efficiency of the system is deteriorated. On the other hand, if the value of the limit multiplicity decreases at a stretch, the CPU usage rate decreases rapidly, causing a problem that resources cannot be used effectively and the overall processing efficiency deteriorates.

  The present invention has been made to solve such a problem, and reduces the administrative burden for flow control, and appropriately improves the processing efficiency of the system by appropriately controlling the flow of threads. The purpose is to be able to.

In order to solve the above-described problem, in the present invention, it is determined whether or not the CPU usage rate measured by the CPU usage rate measuring unit during execution of the thread is within the optimum usage range, and is determined not to be entered. In this case, the appropriate number of threads that limit the number of threads that can be activated simultaneously is changed at a predetermined rate. At this time, if it is determined that the CPU usage rate is below the CPU optimum usage range, the appropriate thread count is increased by a predetermined ratio within a range not exceeding the maximum thread count that is the maximum value that can be taken as the proper thread count. . Also, if the CPU utilization is determined to exceed the CPU optimal range of use, reducing the number of appropriate threads in a predetermined ratio by the minimum value minimum number of threads to fall below it should not be a range which is can take a proper threads Let Further, when the measured CPU usage rate falls within the optimum usage range, the appropriate number of threads is fixed to the value at that time.

  According to the present invention configured as described above, the flow rate control is not performed based on the limit multiplicity set for each thread, but the usage rate of the CPU actually used in the entire activated thread is Since the flow rate control is performed based on whether or not it is within the optimum use range, it is not necessary to previously create table information storing design values for each thread for the flow rate control. In the present invention, all that is required for the flow rate control is setting of parameters such as the optimum CPU usage range and the maximum number of threads, so that there is almost no administrative load.

  Further, according to the present invention, when the measured CPU usage rate is not within the optimum usage range, the appropriate number of threads is determined regardless of the difference between the actual CPU usage rate and the optimum usage range. Will be changed at a rate of. As a result, the number of appropriate threads does not change drastically, the number of threads activated simultaneously increases gradually, and the CPU usage rate gradually approaches the optimum usage range accordingly. Therefore, it is possible to suppress the problem that the system processing efficiency deteriorates due to the rapid increase in the CPU usage rate, or the system resources cannot be effectively utilized due to the rapid decrease in the CPU usage rate. Efficiency can be improved.

It is a block diagram which shows the function structural example of the flow control apparatus by this embodiment. It is a figure which shows the parameter memorize | stored in the parameter memory | storage part of this embodiment. It is a figure for demonstrating the specific processing content of the appropriate thread number change part of this embodiment. It is a figure for demonstrating the processing content by the thread starting part of this embodiment. It is a flowchart which shows the operation example regarding the change (flow control) of the number of appropriate threads performed by the flow control apparatus by this embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a functional configuration example of the flow control device according to the present embodiment. As shown in FIG. 1, the flow rate control device 10 of the present embodiment includes, as its functional configuration, a parameter storage unit 11, a CPU usage rate measurement unit 12, a CPU usage rate determination unit 13, an appropriate thread number changing unit 14, and the number of changes. A measurement unit 15, a flow rate control table storage unit 16, and a thread activation unit 17 are provided. The flow control device 10 is actually configured with a computer CPU or MPU, RAM, ROM, and the like, and the above-described functional configurations are realized by the operation of the flow control program stored in the RAM or ROM. Is done.

  The parameter storage unit 11 is a recording medium that stores various parameters used when performing thread flow control. FIG. 2 is a diagram illustrating parameters stored in the parameter storage unit 11. As shown in FIG. 2, in the present embodiment, the parameter storage unit 11 stores the maximum thread number ThMAX, the minimum thread number ThMIN, the CPU optimum usage range RgOPT, the change confirmation interval INT, and the maximum change count CNT as parameters.

  The maximum thread number ThMAX is a parameter that represents the maximum value of the appropriate thread number that limits the number of threads that can be started simultaneously. In general, as the number of threads activated simultaneously increases, the CPU usage rate increases. Therefore, in order to prevent the CPU usage rate from becoming excessively large, it is necessary to limit the number of threads that can be activated simultaneously. The appropriate number of threads determines the upper limit of the number of threads that can be activated simultaneously.

  In the thread flow control, the set value of the appropriate number of threads is dynamically changed according to the CPU usage rate, and a parameter called the maximum thread number ThMAX represents the maximum value of the settable appropriate number of threads. On the contrary, the minimum thread number ThMIN represents the minimum value of the appropriate number of threads that can be set. In this embodiment, as an example, the maximum thread number ThMAX = 20 and the minimum thread number ThMIN = 3.

  The CPU optimum usage range RgOPT is a parameter that represents the optimum range of the CPU usage rate. That is, the CPU optimum usage range RgOPT represents a target range of CPU usage rate that is desired to be maintained by controlling the flow rate of the thread. In the present embodiment, as an example, the CPU usage rate = 70 ± 5% range is set as the CPU optimum usage range RgOPT. The change confirmation interval INT is a parameter representing a time interval for confirming whether or not to change the setting value of the appropriate number of threads. In this embodiment, as an example, the change confirmation interval INT = 1 second.

  The maximum number of changes CNT is a parameter that represents the maximum value of the number of times that the appropriate thread number changing unit 14 continuously changes the appropriate thread number at a predetermined rate, as will be described later. That is, the number of times the appropriate thread number changing unit 14 continuously changes the appropriate thread number at a predetermined rate is limited by a parameter called the maximum change number CNT. In the present embodiment, as an example, the maximum change count CNT = 10.

  The CPU usage rate measurement unit 12 measures the actual usage rate of the CPU. The CPU usage rate is the ratio of the time during which the CPU is not performing any processing within a certain unit time to the time during which the CPU is performing some processing according to the OS or application program. It is a value indicating

  The CPU usage rate determination unit 13 determines whether or not the CPU usage rate measured by the CPU usage rate measurement unit 12 is within the CPU optimum usage range RgOPT stored in the parameter storage unit 11. That is, in the present embodiment, the CPU usage rate determination unit 13 determines whether or not the actually measured CPU usage rate is within a range of 65 to 75%. This determination is performed every second according to the parameter of the change confirmation interval INT stored in the parameter storage unit 11.

  The appropriate thread number changing unit 14 changes the set value of the appropriate thread number stored in the flow rate control table storage unit 16 in accordance with the determination result by the CPU usage rate determining unit 13. Specifically, when the CPU usage rate measured by the CPU usage rate measurement unit 12 falls within the optimal CPU usage range RgOPT of 65 to 75%, the appropriate thread number changing unit 14 determines that the CPU usage rate determination unit 13 If it is determined, the appropriate number of threads is fixed to the current value. That is, the set value of the appropriate number of threads stored in the flow rate control table storage unit 16 is not updated.

  On the other hand, when the CPU usage rate determination unit 13 determines that the measured value of the CPU usage rate does not fall within the CPU optimum usage range RgOPT, the appropriate thread number changing unit 14 stores the maximum stored in the parameter storage unit 11. The appropriate number of threads stored in the flow rate control table storage unit 16 is changed at a predetermined rate within a range that does not fall below the number of threads ThMAX and the minimum number of threads ThMIN.

  Here, the predetermined ratio can be arbitrarily determined, but it is preferable to set the predetermined ratio to a relatively small value so that the number of simultaneous activations of threads does not increase at a stretch by changing the appropriate number of threads. In the present embodiment, the predetermined ratio = 1. That is, the appropriate thread number changing unit 14 increases or decreases the appropriate thread number by one when the CPU usage rate determination unit 13 determines that the measured value of the CPU usage rate is not within the CPU optimum usage range RgOPT. Let

  FIG. 3 is a diagram for explaining specific processing contents of the appropriate thread number changing unit 14. In the determination performed by the CPU usage rate determination unit 13 every second, when it is determined that the CPU usage rate is below the CPU optimum usage range RgOPT, that is, in the zone A where the CPU usage rate is less than 65% in FIG. If it belongs, the appropriate thread number changing unit 14 determines the appropriate number of threads in the flow rate control table storage unit 16 every time it does not exceed the maximum thread number ThMAX (= 20) stored in the parameter storage unit 11. Increase by one.

  On the other hand, in the determination performed by the CPU usage rate determination unit 13 every second, if it is determined that the CPU usage rate exceeds the CPU optimum usage range RgOPT, that is, the zone where the CPU usage rate is higher than 75% in FIG. If it belongs to C, the appropriate thread number changing unit 14 determines the appropriate number of threads in the flow rate control table storage unit 16 within a range that does not fall below the minimum thread number ThMIN (= 3) stored in the parameter storage unit 11. Decrease by 1 each time.

  If the appropriate thread number changing unit 14 increases the appropriate thread number one by one when the CPU usage rate belongs to the zone A, the simultaneous activation number of threads gradually increases. Accordingly, the CPU usage rate gradually increases. When the CPU usage rate falls within the CPU optimum usage range RgOPT of the zone B, the appropriate thread number changing unit 14 stops the process of increasing the set value of the appropriate thread number, and maintains the appropriate thread number at that time.

  Similarly, when the CPU usage rate belongs to zone C and the appropriate thread number changing unit 14 decreases the appropriate thread number one by one, the number of simultaneous activations of threads gradually decreases. Along with this, the CPU usage rate gradually decreases. When the CPU usage rate falls within the CPU optimum usage range RgOPT of the zone B, the appropriate thread number changing unit 14 stops the process of reducing the set value of the appropriate thread number, and maintains the appropriate thread number at that time.

  The number-of-changes measurement unit 15 measures the number of times the appropriate number of threads has been changed by the appropriate number of threads changing unit 14. That is, when the CPU usage rate belongs to zone A, the change count measurement unit 15 measures the number of times that the appropriate thread number change unit 14 increases the appropriate thread number by one per second. In addition, when the CPU usage rate belongs to zone C, the change count measurement unit 15 measures the number of times that the appropriate thread number change unit 14 decreases the appropriate thread count by one per second.

  The above-described appropriate thread number changing unit 14 increases the appropriate thread number by one when the CPU usage rate determining unit 13 determines that the measured value of the CPU usage rate is below the CPU optimum usage range RgOPT. When the value measured by the number-of-changes measurement unit 15 reaches the maximum number of changes CNT (= 10 times), the flow control table is stored instead of increasing the appropriate thread number by one. The appropriate number of threads of the unit 16 is changed to the maximum number of threads ThMAX.

  Further, the appropriate thread number changing unit 14 reduces the appropriate thread number by one when the CPU usage rate determining unit 13 determines that the measured value of the CPU usage rate exceeds the CPU optimal usage range RgOPT. When the value measured by the number-of-changes measurement unit 15 reaches the maximum number of changes CNT (= 10 times), the flow control table is stored instead of decreasing the appropriate number of threads one by one. The appropriate number of threads in the unit 16 is changed to the minimum number of threads ThMIN.

  As described above, in principle, the appropriate number of threads in the flow rate control table storage unit 16 is changed one by one so that the number of simultaneous activations of threads does not increase or decrease all at once. However, if the CPU usage rate still does not fall within the CPU optimum usage range RgOPT even after the appropriate number of threads has been changed ten times continuously, the CPU usage rate should fall within the CPU optimum usage range RgOPT sooner. , The appropriate thread number is changed to the maximum value (maximum thread number ThMAX) or the minimum value (minimum thread number ThMIN) that can be set as the appropriate thread number.

  The thread activation unit 17 activates one or more threads with the appropriate number of threads stored in the flow rate control table storage unit 16 as an upper limit. The activated thread executes processing of the OS and application program. Specifically, as shown in FIG. 4, each active thread acquires, one by one, transactions placed in a queue that holds data in a first-in first-out (FIFO) list structure. The completed transaction.

  Next, the operation of the flow control device 10 according to the present embodiment configured as described above will be described. FIG. 5 is a flowchart showing an operation example related to the change of the appropriate number of threads (flow rate control) performed by the flow rate control device 10 according to the present embodiment. The flowchart shown in FIG. 5 starts when the flow control device 10 is turned on.

  In FIG. 5, first, the CPU usage rate measuring unit 12 measures the CPU usage rate (step S1). Next, the CPU usage rate determination unit 13 determines whether or not the CPU usage rate measured by the CPU usage rate measurement unit 12 in step S1 is below 65%, which is the lower limit value of the CPU optimum usage range RgOPT ( Step S2). Here, when the CPU usage rate determination unit 13 determines that the CPU usage rate is less than 65%, the CPU usage rate determination unit 13 determines the CPU usage rate (illustrated) previously measured by the CPU usage rate measurement unit 12. It is determined whether or not (stored in the memory not to be stored) exceeds 75%, which is the upper limit value of the CPU optimum use range RgOPT (step S3).

  Here, when it is determined that the previous CPU usage rate has exceeded 75%, the previous CPU usage rate is in the zone C of FIG. 3 and the current CPU usage rate has suddenly moved to the zone A. Become. In this case, the change count measurement unit 15 clears the count value of the change count of the appropriate thread count to zero (step S4), and the process jumps to step S7.

  The reason why the count value of the number of changes of the appropriate thread number is cleared to zero in this way is as follows. For example, when the CPU usage rate is in zone C, the CPU usage rate suddenly moves to zone A after the appropriate number of threads has been changed nine times. In this case, the number of changes of the appropriate thread number becomes the maximum change number CNT (= 10 times) only by changing the appropriate thread number once in the zone A, and the set value of the appropriate thread number is the maximum thread number ThMAX all at once. (The flow from step S5 to step S9). Therefore, in order to prevent this, when the CPU usage rate suddenly shifts from zone C to zone A, the count value of the number of changes of the appropriate number of threads is cleared to zero.

  On the other hand, if it is determined in step S3 that the previous CPU usage rate does not exceed 75%, the appropriate thread number changing unit 14 has changed the appropriate thread number measured by the change number measuring unit 15 10 times. Is determined (step S5).

  Here, when it is determined that the number of changes of the appropriate thread number has not yet reached 10, the appropriate thread number changing unit 14 refers to the flow rate control table storage unit 16 and the set value of the appropriate thread number is the maximum number of threads. It is determined whether or not it is ThMAX (step S6). If the setting value of the appropriate thread number is not equal to the maximum thread number ThMAX, the appropriate thread number changing unit 14 increases the appropriate thread number in the flow rate control table storage unit 16 by 1 (step S7). In response to this, the change count measurement unit 15 increments the count value of the change count of the appropriate thread count (step S8).

  On the other hand, if it is determined in step S6 that the setting value of the appropriate thread number is the maximum thread number ThMAX, the appropriate thread number changing unit 14 maintains the appropriate thread number in the flow control table storage unit 16 without updating it. To do. In this case, the change count measurement unit 15 clears the count value of the change count of the appropriate thread count to zero (step S20).

  If it is determined in step S5 that the number of changes of the appropriate thread number has reached 10, the appropriate thread number changing unit 14 changes the appropriate thread number in the flow control table storage unit 16 to the maximum thread number ThMAX. (Step S9). Thereafter, the change count measurement unit 15 clears the count value of the change count of the appropriate thread count to zero (step S10).

  When the CPU usage rate determination unit 13 determines in step S2 that the CPU usage rate is not less than 65%, the CPU usage rate determination unit 13 continues to measure the CPU usage rate measurement unit 12 in step S1. It is determined whether or not the CPU usage rate exceeds 75%, which is the upper limit value of the CPU optimum usage range RgOPT (step S11). Here, when the CPU usage rate determination unit 13 determines that the CPU usage rate exceeds 75%, the CPU usage rate determination unit 13 determines that the CPU usage rate measured last time by the CPU usage rate measurement unit 12 is It is determined whether or not the value is below 65%, which is the lower limit value of the CPU optimum usage range RgOPT (step S12).

  Here, when it is determined that the previous CPU usage rate is less than 65%, the previous CPU usage rate is in zone A in FIG. 3, and the current CPU usage rate has suddenly moved to zone C. Become. In this case, the change count measurement unit 15 clears the count value of the change count of the appropriate thread count to zero (step S13), and the process jumps to step S16. On the other hand, if it is determined in step S12 that the previous CPU usage rate has not fallen below 65%, the appropriate thread number changing unit 14 has changed the appropriate thread number measured by the change number measuring unit 15 10 times. Is determined (step S14).

  Here, when it is determined that the number of changes of the appropriate thread number has not yet reached 10, the appropriate thread number changing unit 14 refers to the flow rate control table storage unit 16 and the setting value of the appropriate thread number is the minimum thread number. It is determined whether or not it is ThMIN (step S15). If the current value of the appropriate thread number is not equal to the minimum thread number ThMIN, the appropriate thread number changing unit 14 decreases the appropriate thread number in the flow rate control table storage unit 16 by 1 (step S16). In response to this, the change count measurement unit 15 increments the count value of the change count of the appropriate thread count (step S17).

  On the other hand, if it is determined in step S15 that the setting value of the appropriate thread number is the minimum thread number ThMIN, the appropriate thread number changing unit 14 maintains the appropriate thread number in the flow control table storage unit 16 without updating it. To do. In this case, the change count measurement unit 15 clears the count value of the change count of the appropriate thread count to zero (step S20).

  If it is determined in step S14 that the number of changes of the appropriate thread number has reached 10, the appropriate thread number changing unit 14 changes the appropriate thread number in the flow control table storage unit 16 to the minimum thread number ThMIN. (Step S18). Thereafter, the change count measurement unit 15 clears the count value of the change count of the appropriate thread count to zero (step S19).

  When the CPU usage rate determination unit 13 determines in step S11 that the CPU usage rate does not exceed 75%, the CPU usage rate is within the CPU optimum usage range RgOPT. In this case, the appropriate thread number changing unit 14 maintains the appropriate number of threads in the flow rate control table storage unit 16 without updating it. In this case, the change count measurement unit 15 clears the count value of the change count of the appropriate thread count to zero (step S20).

  After the processes in steps S8, S10, S17, S19, and S20, the flow control device 10 determines whether or not the power is turned off (step S21). If it is determined that the power is not turned off, the process returns to step S1. On the other hand, when it is determined that the power is turned off, the operation of the flowchart shown in FIG. 5 ends.

  As described above in detail, in this embodiment, it is determined whether or not the CPU usage rate measured by the CPU usage rate measurement unit 12 during execution of the thread is within the CPU optimum usage range RgOPT. When judged, the appropriate number of threads is changed. As described above, according to the present embodiment, the flow rate control is not performed based on the limit multiplicity set for each thread, but the usage rate of the CPU that is actually used in the entire activated thread is optimal. Since the flow rate control is performed based on whether or not it is within the use range RgOPT, it is not necessary to previously create table information storing design values for each thread for the flow rate control. In this embodiment, since only a few parameters to be stored in the parameter storage unit 11 need to be set for the flow rate control, the administrative load can be significantly reduced.

  Further, in the present embodiment, since it is not necessary to create the table information as described above, the present invention can be applied to a large-scale system in which the number of running programs is large and the CPU usage rate changes every moment. For example, in online transaction processing (hereinafter referred to as OLTP) used in a bank ATM system or the like, the processing time per transaction is very short, and the processing amount per unit time changes every moment. Since the number of transaction requests changes from moment to moment, it is not possible to determine a quantitative processing amount per unit time. That is, it is difficult to predict in advance how much threads should be multiplexed. For this reason, in OLTP, it is extremely difficult to create in advance table information that stores design values of limit multiplicity for each thread. On the other hand, in the present embodiment, it is not necessary to create table information of design values. Therefore, more optimized thread flow control is performed even in a large-scale system such as OLTP in which the CPU usage rate changes every moment. It is possible.

  Further, according to the present embodiment, when the measured CPU usage rate is not within the CPU optimum usage range RgOPT, the CPU usage rate is appropriate regardless of the difference between the actual CPU usage rate and the CPU optimum usage range RgOPT. In principle, the number of threads is changed one by one. As a result, the number of appropriate threads does not change drastically, the number of threads activated simultaneously increases gradually, and the CPU usage rate gradually approaches the CPU optimum usage range RgOPT. Therefore, the system processing efficiency does not deteriorate when the CPU usage rate suddenly increases, and the system resources cannot be effectively used due to the CPU usage rate decreasing rapidly. Can be improved.

  In this embodiment, if the CPU usage rate still does not fall within the CPU optimum usage range RgOPT even after the appropriate number of threads is changed ten times in succession, the optimum number of threads in the flow rate control table storage unit 16 is maximized. The number of threads is changed to ThMAX or the minimum number of threads ThMIN. It is not always necessary to control the appropriate number of threads according to the number of changes, but by doing so, the processing efficiency of the system can be further improved. By gradually changing the appropriate number of threads to improve the processing efficiency of the system and gradually changing the appropriate number of threads to some extent, the CPU usage rate becomes faster and the CPU optimum usage range This is because it enters RgOPT.

  In the above embodiment, the example in which the appropriate number of threads is changed one by one has been described, but this is merely an example. The predetermined ratio of gradually changing the appropriate number of threads is, for example, a predetermined value of 1 / x (x is a divisor of the maximum number of threads ThMAX, 2 or more) with respect to the value of the maximum number of threads ThMAX. A predetermined ratio may be determined in relation to the maximum number of threads ThMAX, such as a ratio. Further, the predetermined ratio of gradually changing the appropriate thread number may be different depending on whether the appropriate thread number is increased or decreased.

  Further, the predetermined ratio of gradually changing the appropriate number of threads may be varied according to the number of changes of the appropriate number of threads measured by the change count measuring unit 15. For example, when the number of changes of the appropriate thread number is up to n (1 ≦ n <CNT), the current appropriate thread number set in the flow control table storage unit 16 and the maximum thread number ThMAX or the minimum thread number ThMIN Is calculated, and the appropriate number of threads is changed to the average value. Then, when the number of changes of the appropriate thread number is more than n times, the appropriate thread number may be changed one by one.

  This will be described with a specific example. Here, n = 1. For example, it is assumed that the current number of appropriate threads set in the flow control table storage unit 16 is 6, and the CPU usage rate at that time is in the zone B in FIG. Thereafter, it is assumed that the CPU usage rate transitions from zone B to zone A. In this case, the appropriate thread number changing unit 14 is the average value (= 13.5) of the current appropriate thread number (= 6) set in the flow rate control table storage unit 16 and the maximum thread number ThMAX (= 20). And the appropriate number of threads is changed to a value obtained by rounding up or down the decimal point of the average value. If the CPU usage rate does not return to zone B and remains in zone A even after the appropriate number of threads is changed in this way, the appropriate number of threads is increased by one thereafter.

  In this way, when the CPU usage rate is not within the CPU optimum usage range RgOPT (in the zone A or the zone C in FIG. 3), the appropriate number of threads is not increased or decreased linearly, It can be increased or decreased logarithmically. As a result, it is possible to make the CPU usage rate enter the CPU optimum usage range RgOPT earlier while gradually increasing or decreasing the CPU usage rate by gradually changing the appropriate number of threads.

  Such an operation is effective when it is performed between when the flow rate control device 10 is powered on and when the CPU usage rate first enters the zone B. Immediately after the power is turned on, the CPU usage rate is expected to vary greatly. However, by performing the above-described operation, the CPU usage rate can enter the CPU optimum usage range RgOPT of the zone B as soon as possible. .

  In this case, the appropriate thread number changing unit 14 is set in the flow rate control table storage unit 16 when the CPU usage rate measured by the CPU usage rate measurement unit 12 at the time of power-on belongs to the zone A smaller than 65%. An average value of the default appropriate thread number and the maximum thread number ThMAX (= 20) is calculated, and the appropriate thread number is changed to a value obtained by rounding up or down the decimal point of the average value. When the CPU usage rate measured by the CPU usage rate measurement unit 12 when the power is turned on belongs to the zone C larger than 75%, the appropriate thread number changing unit 14 is set in the flow rate control table storage unit 16. An average value of the default appropriate thread number and the minimum thread number ThMIN (= 3) is calculated, and the appropriate thread number is changed to a value obtained by rounding up or down the decimal point of the average value.

  In the above embodiment, the minimum thread number ThMIN is set as a parameter, but this is not always necessary. That is, for the purpose of preventing the CPU usage rate from becoming excessively high, only the maximum thread number ThMAX may be set as a parameter.

  Moreover, although the said embodiment demonstrated the example which changes an appropriate thread number when the present value of CPU usage rate measured by the CPU usage rate measurement part 12 is not in CPU optimal usage range RgOPT, this invention is described. It is not limited to this. For example, the appropriate number of threads may be changed when the average value of the CPU usage rate for the latest several times measured every second by the CPU usage rate measurement unit 12 is not within the CPU optimum usage range RgOPT. Alternatively, the ratio of the number of times when the CPU usage rate is not within the CPU optimum usage range RgOPT in the unit number of times (for example, 10 times) for measuring the CPU usage rate by the CPU usage rate measurement unit 12 exceeds a predetermined value. It is also possible to change the appropriate number of threads. Such an adjustment method is preferably applied to a system in which the fluctuation amplitude of the CPU usage rate is relatively large. On the other hand, the method of adjusting the appropriate number of threads based on the current value of the CPU usage rate is preferably applied to a system in which the fluctuation amplitude of the CPU usage rate is relatively small.

  In addition, each of the above-described embodiments is merely an example of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. In other words, the present invention can be implemented in various forms without departing from the spirit or main features thereof.

DESCRIPTION OF SYMBOLS 10 Flow control apparatus 11 Parameter memory | storage part 12 CPU usage rate measurement part 13 CPU usage rate determination part 14 Appropriate thread number change part 15 Change frequency measurement part 16 Flow control table memory | storage part 17 Thread starting part

Claims (5)

Parameters including the maximum number of threads that represents the maximum value of the appropriate number of threads that limit the number of threads that can be started simultaneously, the minimum number of threads that represents the minimum value of the appropriate number of threads , and the optimal range of CPU that represents the optimal range of CPU usage Stored parameter storage unit;
CPU usage rate measuring unit for measuring the CPU usage rate,
A CPU usage rate determination unit that determines whether the CPU usage rate measured by the CPU usage rate measurement unit is within the CPU optimum usage range stored in the parameter storage unit;
When the CPU usage rate determining unit determines that the CPU usage rate is within the CPU optimum usage range, the CPU usage rate determining unit fixes the appropriate number of threads to the current value. When it is determined that the CPU usage rate is not within the CPU optimum usage range, the appropriate thread count is changed at a predetermined ratio within a range not exceeding the maximum thread count stored in the parameter storage unit. and an appropriate number of threads changing unit that,
When the CPU usage rate determination unit determines that the CPU usage rate is below the CPU optimal usage range, the appropriate thread number changing unit sets the maximum thread number stored in the parameter storage unit. If the CPU usage rate determination unit determines that the CPU usage rate exceeds the CPU optimal usage range while increasing the appropriate number of threads at a predetermined rate within a range not exceeding, the parameter storage unit A flow rate control device, wherein the appropriate number of threads is decreased at a predetermined rate within a range not less than the minimum number of stored threads . A change number measuring unit that measures the number of times the appropriate thread number has been changed by the appropriate thread number changing unit;
The appropriate thread number changing unit performs a process of increasing the appropriate thread number at a predetermined rate when the CPU usage rate determining unit determines that the CPU usage rate is below the CPU optimal usage range. When the value measured by the number-of-changes measurement unit reaches a predetermined value, the appropriate number of threads is changed to the maximum number of threads instead of increasing the appropriate number of threads at a predetermined rate. The flow rate control device according to claim 1 . A change number measuring unit that measures the number of times the appropriate thread number has been changed by the appropriate thread number changing unit;
When the CPU usage rate determination unit determines that the CPU usage rate exceeds the CPU optimal usage range, the appropriate thread number changing unit performs a process of reducing the appropriate thread number at a predetermined rate. When the value measured by the number-of-changes measurement unit reaches a predetermined value, the appropriate number of threads is changed to the minimum number of threads instead of decreasing the appropriate number of threads at a predetermined rate. The flow rate control device according to claim 1 . A first step of measuring CPU utilization;
A second determination is made as to whether or not the CPU usage rate measured in the first step is within the CPU optimal usage range stored in the parameter storage unit as a parameter representing the optimal range of CPU usage rate. And the steps
A third step of determining whether the CPU usage rate measured in the second step is below or above the CPU optimum usage range;
When it is determined in the third step that the CPU usage rate is below the CPU optimum usage range, the parameter storage unit is used as a parameter representing the maximum value of the appropriate number of threads that limits the number of threads that can be activated simultaneously. A fourth step of increasing the appropriate number of threads at a predetermined rate within a range not exceeding the maximum number of threads stored in
The minimum number of threads stored in the parameter storage unit as a parameter representing the minimum value of the appropriate number of threads when it is determined in the third step that the CPU usage rate exceeds the CPU optimum usage range And a fifth step of reducing the appropriate number of threads at a predetermined rate within a range not falling below . CPU usage rate measuring means for measuring CPU usage rate,
CPU for determining whether or not the CPU usage rate measured by the CPU usage rate measuring means is within the CPU optimal usage range stored in the parameter storage unit as a parameter representing the optimal range of CPU usage rate When the CPU usage rate is determined to be below the CPU optimum usage range by the usage rate determination unit and the CPU usage rate determination unit, the maximum value of the appropriate number of threads that limits the number of threads that can be started simultaneously is set. While the appropriate number of threads is increased at a predetermined rate within a range not exceeding the maximum number of threads stored in the parameter storage unit as a parameter to represent , the CPU usage rate is determined by the CPU usage rate determining unit. If it is determined that the number of An appropriate thread number changing means for reducing the appropriate thread number by a predetermined ratio within a range not less than the minimum thread number stored in the parameter storage unit;
A computer-readable flow control program for causing a computer to function as a computer.