JP2007172519A - Information processor, link management method for software module, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize and speed up a processing speed. <P>SOLUTION: The information processor has: a software module execution means for executing the software module; a main storage means for arranging software modules executed by the execution means; a sub-storage means for storing a plurality of software modules; and a software module management means for calculating the frequency of access to the software modules and managing the software modules on the basis of the calculated frequency of access. The software module management means calculates the frequency of access to the software modules when the execution of software modules arranged by the main storage means from the sub-storage means is completed, and leaves the software modules whose frequency of access is higher than a specified threshold value in the main storage means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an information processing apparatus, a software module link management method, and a program that dynamically manage link of software modules according to access frequency.

  Dynamic link management of software modules has been widely adopted by OSs such as personal computers, but there has been no means or method for automatically controlling the residency in the main memory in units of software modules. For this reason, memory management by paging processing such as LRU (Least Recently Used) and LFU (Least Frequently Used) is generally used. Therefore, there is a problem that it is not suitable for adaptation to a real-time system, etc. Also, there is a problem that the system (device) becomes unstable because unnecessary memory increases as time passes. It was.

  Also, in the embedded system, the number of systems using a general-purpose OS is increasing mainly in digital home appliances and car navigation systems. However, the above problems are caused by the general-purpose OS in embedded systems where memory resources are more limited. There is a tendency to be prominently seen in the system adopting. In addition, as an embedded system, there is a strong desire to draw out the processing power of a weak CPU device as much as possible.

As an example of the prior art, by setting the reference count (access frequency) to a predetermined maximum value for a page that is not to be swapped, it is possible to make the page that is least likely to be swapped regardless of the actual reference count. There is an “application program interface that controls the allocation of physical memory in a virtual storage system by an application program” (see, for example, Patent Document 1).
JP 2004-500605 A

  However, in the invention described in Patent Document 1, it is not possible to set a threshold for the number of references so as not to swap pages whose actual number of references is equal to or greater than the threshold. That is, based on the actual access frequency, a software module with a high access frequency cannot be left in the main memory.

  The present invention has been made in view of the above circumstances, and an information processing apparatus, a software module link management method, and a program capable of leaving a software module with a high access frequency in a main memory based on an actual access frequency The purpose is to provide.

  In order to achieve this object, the invention described in claim 1 is characterized in that the software module is managed based on the access frequency set in the software module.

  According to a second aspect of the present invention, in the first aspect of the present invention, a software module executing unit that executes the software module, a main storage unit in which the software module that the executing unit executes is arranged, and a plurality of software modules are stored. Sub-storage means, and software module management means for managing the software module based on the calculated access frequency. The software module management means includes: At the end of execution of the software module arranged in the main storage means, the access frequency for the software module is calculated, and the software module whose access frequency is higher than a predetermined threshold is left in the main storage means.

  The invention described in claim 3 is the invention according to claim 2, wherein the software module management means deletes the software module whose access frequency is lower than a preset threshold from the main storage means.

  According to a fourth aspect of the present invention, in the second or third aspect of the invention, there is provided timer means for measuring a time for use in calculating the access frequency, and the software module management means is a predetermined time measured by the timer means. The access frequency is calculated on the basis of the number of accesses to the same software module within the time.

  The invention according to claim 5 is a software module link management method performed by the information processing apparatus, wherein access frequency is set to the software module, and the software module is managed based on the access frequency.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, at the end of execution of a predetermined software module, the access frequency for the software module is calculated, and the software module whose access frequency is higher than a predetermined threshold value is left in the main memory means. It is characterized by that.

  According to a seventh aspect of the invention, in the sixth aspect of the invention, when the execution of the predetermined software module is finished, the access frequency to the software module is calculated, and the software module whose access frequency is lower than a preset threshold is stored in the main memory means. It is characterized by deleting from.

  The invention according to claim 8 is the invention according to claim 6 or 7, wherein the time used for calculating the access frequency is measured, and based on the number of accesses to the same software module within the measured predetermined time, The access frequency is calculated.

  The invention according to claim 9 is a program for causing an information processing apparatus to execute a software module link management method, and sets information on an access frequency for the software module and manages software module management based on the access frequency. The processing apparatus is executed.

  According to a tenth aspect of the present invention, in the ninth aspect of the invention, at the end of execution of a predetermined software module, an access frequency to the software module is calculated, and a software module whose access frequency is higher than a predetermined threshold is left in the main storage means. The information processing apparatus is caused to execute the processing.

  According to an eleventh aspect of the present invention, in the tenth aspect of the present invention, at the end of execution of a predetermined software module, the access frequency for the software module is calculated, and the software module whose access frequency is lower than a preset threshold is stored in the main memory means. The information processing apparatus is caused to execute processing for deleting from the information processing apparatus.

  The invention according to claim 12 is the invention according to claim 10 or 11, wherein the time used for calculating the access frequency is measured, and based on the number of accesses to the same software module within the measured predetermined time, The information processing apparatus is caused to execute processing for calculating access frequency.

  According to the present invention, since a software module with a high access frequency can be left in the main memory based on the actual access frequency, the processing speed can be optimized and increased.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  Conventionally, in a normal information processing apparatus such as a personal computer, when a software module to be dynamically linked exists in a secondary storage device, when this software module is arranged in a main memory (main memory) for processing, a physical memory Since the arrangement depends on the cache memory, the access efficiency in the local address space arranged in the cache memory is improved in the software module having a large capacity. However, in this method, dynamic allocation management to the physical memory in software module units is not performed, so even in the case of frequently accessed software modules, reading from the secondary storage device to the physical memory occurs every time. The processing speed decreases.

  Conventionally, there is a paging process by LFU as a means of efficiently using the main memory. However, this simply replaces a part having a low access frequency, so that the access frequency is relatively low regardless of the access frequency value. It is excluded from the main memory from the lowest. Therefore, depending on the situation, software modules that are desirably originally in the main memory may be excluded, and processing efficiency may be lowered.

FIG. 6 shows an operation conceptual diagram describing the difference between the LFU as a conventional paging technique and the present invention.
In the conventional software module management by LFU, as shown in FIG. 6A, for example, software A, B, C, and D are arranged in descending order of access frequency in the main memory as the main storage means. When the software G, F, and E are executed, the modules with the lower access frequency are replaced in order, so that the software C and D are forcibly replaced due to the limitation of the main memory as shown in FIG. End up. However, for example, when this software C is a module that requires real-time processing and is called periodically, it is necessary to leave the software C on the main memory. The reason is that real-time responsiveness and system performance are deteriorated and the maximum response time is increased.

  Therefore, in the module management according to the present invention, as shown in FIG. 6C, a threshold value is set for the access frequency and is replaced in ascending order of the access frequency as in the prior art, but modules that are equal to or higher than the threshold value are not replaced. Thus, for example, even if the software C is a module that requires real-time processing and is called periodically, the software C exceeds the threshold value, and therefore remains on the main memory as shown in FIG. The conventional system failure does not occur. Note that the software G waits for execution.

  As described above, according to the present invention, in an information processing apparatus that performs dynamic link management of software modules, the module access frequency is managed, and a module with a high access frequency (a module whose access frequency is higher than a value set as a threshold value). The processing speed is optimized by automatically arranging in the main memory close to the CPU device.

  Specifically, the present invention refers to the access history by providing an access frequency flag in the software module, and regarding the management of reuse and disposal of the software module once placed in the main memory from the secondary storage device, By comparing the value of the access frequency flag with a preset threshold value, the processing speed can be improved as compared with the conventional information processing apparatus.

  The information processing apparatus for executing the software module link management method of the present invention will be described below. FIG. 1 shows the configuration of the information processing apparatus of this embodiment.

  As shown in FIG. 1, the information processing apparatus of this embodiment includes a main memory (main storage means) 7, a secondary storage device (sub storage means) 8, a cache memory 6, a CPU device (software module execution means) 5, A memory management unit (software module management means) 10 and an interval timer (timer means) 14 are provided.

  The CPU device 5 that executes the software module is connected to the memory management unit 10 via the real address bus 11 and is connected to the cache memory 6 via the cache memory bus 13. The real address bus 11 outputs address information where a software module to be executed by the CPU device 5 exists. The cache memory bus 13 is a data bus that connects the CPU device 5 and the cache memory 6 at high speed.

  The cache memory 6 temporarily stores instructions to be executed by the CPU device 5 and improves processing efficiency in local loop processing or the like. The cache memory 6 is connected to the main memory 7 via the data bus 9.

  The memory management unit 10 converts the information on the real address bus 11 output by the CPU device 5 into a logical address that can be used in the main memory 7, and outputs the information to the logical address bus 12. In the memory management unit 10, the logical address bus 12 is connected to the main memory 7 via the data bus 9.

  In the main memory 7, a plurality of software modules 1 required for the CPU device 5 to perform processing are arranged as necessary.

  The secondary storage device 8 stores a plurality of software modules 1 such as programs. The software module 1 that is required for processing by the CPU device 5 is called into the main memory 7 through the data bus 9 and processed. To do.

  The interval timer 14 is used for time measurement for calculating the access frequency of the software module 1.

  FIG. 2 shows the configuration of the software module 1. As shown in FIG. 2, the software module 1 includes an access frequency flag 3 for managing reuse or discard of the software module 1, a header portion including a module ID 2, and an execution module 4. .

Next, the operation of this embodiment will be described in detail with reference to FIGS.
When the CPU device 5 executes the program, an arbitrary software module 1 that is normally in the secondary storage device 8 is arranged in the main memory 7 through the data bus 9. At this time, the information on the logical address bus 12 for arranging the software module 1 in the main memory 7 is output by the memory management unit 10 based on the information on the real address bus 11 output from the CPU device 5.

  The CPU device 5 reads the execution module 4 of the corresponding software module 1 arranged in the main memory 7 into the cache memory 6 through the data bus 9 and performs processing through the cache memory bus 13.

  At the end of execution of the corresponding software module 1, the memory management unit 10 takes the processing from the CPU device 5, refers to the access frequency flag 3, and does not delete the software module 1 with the module ID 2 having the high access frequency from the main memory 7. leave.

  On the other hand, the software module 1 with low access frequency is excluded from the main memory 7 and the process is returned to the CPU device 5.

  The access frequency is calculated by managing how many times the same software module has been called within a predetermined time by the memory management unit 10 using the module ID 2 by using the interval timer 14.

  FIG. 3 is a flowchart of processing for managing whether to leave the software module 1 in the main memory 7 according to the access frequency in the present embodiment.

  First, the processing end of the execution module 4 is detected (step A1), the access frequency flag 3 is referenced (step A2), and it is determined whether or not the access is the first time (step A3). In the case of the first access (step A3 / YES), the write value of the access frequency flag 3 is set to a predetermined value indicating the accessed state (step A8). Thereafter, the software module 1 is left in the main memory 7 (step A9), the access frequency flag 3 is updated, and the process ends (step A10).

  On the other hand, if it is not the first access in step A2 (step A2 / NO), the memory management unit 10 calculates the access frequency of the corresponding software module 1 within the predetermined time of the interval timer 14 (step A4). .

  If the calculated access frequency value is greater than or equal to an arbitrary value set in advance (step A5 / YES), a process for leaving the corresponding software module 1 is performed (step A9), the access frequency flag 3 is updated, and the process ends. (Step A10). If the access frequency value is less than the set value (step A5 / NO), the access frequency flag is cleared (step A6), and the process of deleting the software module 1 from the main memory 7 is performed (step A7). ).

  As described above, according to the processing of the present embodiment, the software module 1 that is determined to be frequently called by using the access frequency flag 3 is held in the main memory 7 close to the CPU device 5, so that the CPU is conventionally used. Compared to the case where the call waiting time from the device 5 is called from the secondary storage device 8 each time, it is possible to minimize the waiting time, and the processing time of the program is increased.

  Therefore, conventionally, since the software module 1 is present in the secondary storage device 8 such as a hard disk drive, an access time of about several ms is required until it is read into the CPU device. The software module 1 that is frequently called up is placed on the main memory 7, and the access time until it is read into the CPU device is about 0.5 μs, and a high speed of about several thousand times is realized. Is possible.

  For example, if a threshold is set for the access frequency at which a software module that requires real-time responsiveness is called, the target software module remains in the main memory, so that the calling time of this module becomes stable and fast.

An outline of the operation of this embodiment is shown in FIG.
In the conventional module management by LFU, as shown in FIG. 7A, in (1), the first response time includes a read time. In (2), when the scheduled software (programs) E, F, and G interrupts, the existing software is released from the main memory in the order of low access frequency (see FIG. 6). The same applies to software for which responsiveness is important. In (3), the response time becomes the same as the response time in (1). Therefore, the response time becomes unstable.

On the other hand, in the module management of the present embodiment, as shown in FIG. 7B, in (1), the first response time includes the read time. In (2) and (3), by adjusting the access frequency threshold, the software C remains in the main memory, and the response time is stable and improved (it is released when the access frequency decreases). In this way, by locking predetermined software with the access frequency threshold, if there is an access frequency equal to or higher than the threshold, the response time is guaranteed while another interrupt process occurs.
In particular, this embodiment is effective for guaranteeing response processing time when a burst interrupt as shown in FIG. 7C occurs.

  A second embodiment of the present invention will be described with reference to FIG. In the present embodiment, as shown in FIG. 4, the management of the placement of the software module 1 in the main memory 7 is virtually processed by software without having a physical memory management unit. Therefore, compared with the first embodiment, it is realized with a simple hardware configuration.

  The CPU device 5 that executes the software module is connected to the main memory 7 via the data bus 9 and the real address bus 11. In the main memory 7, a plurality of software modules 1 required for the CPU device 5 to perform processing are arranged as necessary. The secondary storage device 8 stores a plurality of software modules 1 such as programs. The software module 1 required for processing by the CPU device 5 is called into the main memory 7 through the data bus 9 and processed. To do. The interval timer 14 is used for time measurement for calculating the access frequency of the software module 1.

Hereinafter, the operation of this embodiment will be described.
When the CPU device 5 executes the program, an arbitrary software module 1 that is normally in the secondary storage device 8 is arranged in the main memory 7 through the data bus 9. At this time, information for placing the memory module 1 in the main memory 7 is implemented based on information on the real address bus 11 output from the CPU device 5.

  The CPU device 5 reads and executes the execution module 4 of the corresponding software module 1 arranged in the main memory 7 through the data bus 9.

  When the execution of the corresponding software module 1 is finished, the CPU device 5 refers to the access frequency flag 3 and leaves the software module 1 with the module ID 2 having a high access frequency without deleting it from the main memory 7.

  On the other hand, the software module 1 with low access frequency is excluded from the main memory 7.

  The access frequency is calculated by the CPU device 5 managing how many times the same software module has been called within a predetermined time by using the interval timer 14 with the module ID 2.

  FIG. 5 is a flowchart of processing for managing whether to leave the software module 1 in the main memory 7 according to the access frequency in the present embodiment.

  First, the processing end of the execution module 4 is detected (step A1), the access frequency flag 3 is referenced (step A2), and it is determined whether or not the access is the first time (step A3). In the case of the first access (step A3 / YES), the write value of the access frequency flag 3 is set to a predetermined value indicating the accessed state (step A8). Thereafter, the software module 1 is left in the main memory 7 (step A9), the access frequency flag 3 is updated, and the process ends (step A10).

  On the other hand, if the access is other than the first access in step A2 (step A2 / NO), the CPU device 5 calculates the access frequency of the corresponding software module 1 within the predetermined time of the interval timer 14 (step A4).

  If the calculated access frequency value is greater than or equal to an arbitrary value set in advance (step A5 / YES), a process for leaving the corresponding software module 1 is performed (step A9), the access frequency flag 3 is updated, and the process ends. (Step A10). If the access frequency value is less than the set value (step A5 / NO), the access frequency flag is cleared (step A6), and the process of deleting the software module 1 from the main memory 7 is performed (step A7). ).

  As described above, according to the processing of the present embodiment, the software module 1 that is determined to be frequently called by using the access frequency flag 3 is held in the main memory 7 close to the CPU device 5, so that the CPU is conventionally used. Compared to the case where the call waiting time from the device 5 is called from the secondary storage device 8 each time, it is possible to minimize the waiting time, and the processing time of the program is increased.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention.

  The present invention can be applied to all embedded systems such as digital home appliances and car navigation systems.

It is a block diagram which shows the structure of the information processing apparatus which concerns on Example 1 of this invention. It is a block diagram which shows the structure of the software module which concerns on Example 1 of this invention. It is a flowchart which shows the operation | movement which concerns on Example 1 of this invention. It is a block diagram which shows the structure of the information processing apparatus which concerns on Example 2 of this invention. It is a flowchart which shows the operation | movement which concerns on Example 2 of this invention. It is a conceptual diagram which shows the difference of operation | movement of a prior art and operation | movement of this invention. It is a conceptual diagram which shows the outline | summary of operation | movement of this invention.

Explanation of symbols

1 Software module 2 Module ID
3 Access frequency flag 4 Execution module 5 CPU device 6 Cache memory 7 Main memory 8 Secondary storage device 9 Data bus 10 Memory management unit 11 Real address bus 12 Logical address bus 13 Cache memory bus 14 Interval timer

Claims (12)

  An information processing apparatus that manages the software module based on an access frequency set for the software module. Software module execution means for executing the software module;
Main storage means in which software modules executed by the execution means are arranged;
A secondary storage means for storing a plurality of software modules;
Software module management means for calculating an access frequency for the software module and managing the software module based on the calculated access frequency;
The software module management means calculates an access frequency to the software module at the end of execution of the software module arranged in the main storage means from the secondary storage means, and selects a software module whose access frequency is higher than a predetermined threshold value. The information processing apparatus according to claim 1, wherein the information processing apparatus is left in the main storage unit.   3. The information processing apparatus according to claim 2, wherein the software module management unit deletes a software module whose access frequency is lower than a preset threshold value from the main storage unit. Timer means for measuring time for use in calculating the access frequency;
4. The information processing apparatus according to claim 2, wherein the software module management unit calculates the access frequency based on the number of accesses to the same software module within a predetermined time measured by the timer unit. . A software module link management method performed in an information processing apparatus,
A software module link management method comprising: setting an access frequency for a software module and managing the software module based on the access frequency.   6. The software module link according to claim 5, wherein when the execution of the predetermined software module is finished, an access frequency to the software module is calculated, and a software module whose access frequency is higher than a predetermined threshold is left in the main storage means. Management method.   The access frequency for the software module is calculated at the end of execution of the predetermined software module, and the software module whose access frequency is lower than a preset threshold is deleted from the main storage unit. Software module link management method. Measure the time used to calculate the access frequency,
8. The software module link management method according to claim 6, wherein the access frequency is calculated based on the measured number of accesses to the same software module within a predetermined time. A program for causing an information processing apparatus to execute a link management method for software modules,
A program that sets an access frequency for a software module and causes an information processing apparatus to execute processing for managing the software module based on the access frequency.   When the execution of a predetermined software module is finished, an access frequency for the software module is calculated, and the information processing apparatus is caused to execute a process of leaving a software module whose access frequency is higher than a predetermined threshold in a main storage unit. Item 10. The program according to Item 9.   Calculating an access frequency for the software module at the end of execution of the predetermined software module, and causing the information processing apparatus to execute a process of deleting a software module whose access frequency is lower than a preset threshold from the main storage unit The program according to claim 10, wherein   Time for use in calculating the access frequency is measured, and the information processing apparatus is caused to execute processing for calculating the access frequency based on the number of accesses to the same software module within the measured predetermined time. The program according to claim 10 or 11.

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