JP3511935B2 - File writing method in multi-thread program - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a file additional writing method for performing exclusive additional writing to a file that is a shared resource in a program.

[0002]

2. Description of the Related Art A multitasking system apparently allocates an independent memory space or I / O space to these programs so that they can be executed simultaneously. As a result, the multitasking system makes each program appear as if it were running. The execution unit of this program is called a process.

However, this multitasking system has a problem in that the speed of the entire system is reduced because the load of process switching processing is heavy. A system using a multithreaded program is used to solve this problem. The execution unit of the task at this time is called a thread. Among threads in the same process, the load of switching between tasks is small, and since the threads share memory, I / O resources, etc., switching can be easily performed.

However, since a plurality of threads operate in parallel in a multi-thread program, it is necessary to synchronize when accessing a shared resource such as a file. Therefore, in a conventional multi-threaded program, when a thread writes data to a file that is a shared resource, it does not access the other thread from the time the corresponding file is opened until it is closed. It is controlled to operate exclusively.

[0005]

However, in the above-mentioned multi-thread program, when writing to a file which is a shared resource, exclusive control is performed from the time the file is opened until the time it is closed. Since the threads cannot operate concurrently, the threads that perform additional writing to the file cannot access the files of other threads, and the advantages of multi-threads such as the improvement of CPU usage efficiency due to the thread parallel operation are lost. There is a problem.

Further, in the above-mentioned multi-thread program, the file which is a shared resource is opened / closed each time each thread accesses the file.
There is a problem that it takes time to perform additional writing to a file which is a shared resource.

The present invention has been made under such a background, and in a multi-thread program, additional writing to a file which is a shared resource can be performed without impairing the improvement of the CPU usage efficiency by the thread parallel operation. Further, when performing additional writing to a file which is a shared resource, there is provided a file additional writing method in a multi-thread program that reduces the number of times this file is opened / closed to shorten the thread operation time.

[0008]

The invention according to claim 1 is
In a file writing method in a multi-thread program including a plurality of threads, a file name of an opened file, a file handle indicating the file, and a thread ID indicating the thread using the file. A file information holding unit that stores a table indicating the relationship between the file name, a file name of a file that is opened under the control of the thread, and a file opening unit that outputs a thread ID indicating the thread, and a thread that is controlled by the thread Thread I
D and a file closing means for outputting a file handle corresponding to the file to be closed, and the file handle corresponding to the file when the thread ID for identifying the thread and the file name of the file to be opened are inputted from the file opening means To get
When this file handle is stored in the file information holding unit in association with this thread ID and this file name, and the thread ID for identifying the thread and the file handle corresponding to the file to be closed are input from the file closing means, File opening / closing exclusive control means for removing the file handle, the file name corresponding to the file handle, and the thread ID from the file information holding unit, the thread ID indicating the thread under the control of the thread, and the file handle indicating the file to be written. And a data writing means for outputting data to be written in the file, a thread ID, a file handle and data to be written in the file which are input from the data writing means, and a file corresponding to the file handle Characterized by comprising a file write exclusive control means for writing the data to the end.

According to a second aspect of the present invention, in the file addition / writing method in the multithread program according to the first aspect, the file opening / closing exclusive control means is a file in the file information holding section in which the file name is described. The name reference / update is exclusively controlled based on the thread ID and the file handle stored in the file information holding unit, and the opening and closing of the file are controlled.

According to a third aspect of the present invention, in the file addition / writing method in the multithreaded program according to the first or second aspect, the file opening / closing exclusive control means sends the thread ID from the file opening means.
And the file name is received, the file information holding unit is referred to, and when it is detected that this file name is not in the file information holding unit, the file corresponding to this file name is opened, and the file handle and the information for each thread are set as the file information. When the file is stored in the holding unit and a file handle is returned and it is detected that the file name of this file name is in the file information holding unit, the file ID is not stored and the thread ID is stored in the file information holding unit. When the handle is output to the file opening means, and when the thread ID and the file handle are received from the file closing means, the thread ID is deleted by referring to the file information holding unit, and the thread ID is completely deleted. If it does not exist, the file is closed and the file The output to the file closing means, if another thread ID does not exist at all, and outputs without closing the file the file handle to the file closing means.

According to a fourth aspect of the present invention, in the file additional writing method in the multithread program according to any one of the first to third aspects, the file write exclusive control means opens the file. The writing of data to the file of the threads other than the thread is exclusively controlled based on the thread ID and the file handle stored in the file information holding unit.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a file writing method according to an embodiment of the present invention.
In the figure, the file writing method according to the embodiment is such that a thread instruction unit 1, a file opening unit 3, a file closing unit 4, a data writing unit 5, a file opening / closing exclusive control unit 6, a file writing exclusive control unit 7, and a file. The information holding unit 8 is provided.

The thread instruction unit 1 is a multi-thread
Instructions (thread ID, file name, etc.) from each thread of the program are output to the file opening means 3, the file closing means 4, and the data writing means 5.

The file opening means 3 receives a thread ID and a file name for opening a file from a thread of a multi-thread program. Further, the file opening means 3 uses the input thread I
The D and the file name are output to the file opening / closing exclusive control means 6. Here, the thread ID is a code for identifying each thread.

Furthermore, when the file opening / closing exclusive control means 6 inputs the file ID corresponding to the thread ID and the file name, the file opening means 3 outputs the file handle corresponding to the file name, the thread ID and the file name. Output to thread. Here, the file handle is the name given to the file to be opened, which identifies each file in the multi-thread program.

The file closing means 4 receives a thread ID and a file handle for closing a file from a thread of a multi-thread program. Further, the file closing means outputs the input thread ID and file handle to the file opening / closing exclusive control means 6.

The file writing means 5 receives the thread ID, the file handle, and the data to be written in the file from the thread. Further, the file writing means 5 is
The data input from the thread is written to the file 2 indicated by the file handle.

The file opening / closing exclusive control means 6 inputs the thread ID and the file name from the file opening means 3 in order to open the file. Further, the file opening / closing exclusive control unit 6 searches for whether the input file name exists in the file information holding unit 8.

At this time, the file opening / closing exclusive control means 6
When the file name input to the file information holding unit 8 does not exist, the newly input file name is written to the file information holding unit 8 and the corresponding file is opened. Further, the file opening / closing exclusive control unit 6 outputs the file handle corresponding to the file name written in the file information holding unit 8 to the file opening unit 3.

The file opening / closing exclusive control means 6 receives the thread ID and the file handle from the file closing means 4 in order to close the file. The file open / close exclusive control unit 6 also removes the file name of the file corresponding to the file handle from the file information holding unit 8 and closes the file.

At this time, the file opening / closing exclusive control means 6
Checks for the existence of other threads that are using the same file, and if other is used, does not remove the corresponding file and does not close the file.

The file information holding unit 8 shows the relationship between the file name and the file handle. Here, if the file name exists in the file information holding unit 8, the file with this file name is open.

FIG. 2 shows the data structure of the file information holding unit 8. In the file name column 9, the opened file name, for example, "AAAA", "BBB", "C"
CCCC ", ... Is written. Further, the file handle column 10 shows the file handle corresponding to the file in the file name column 9. For example, for the file name "AAAA", the file handle "XX
The file handle “YYY” corresponds to the file name “BBB”, and the file handle “ZZZ” corresponds to the file name “CCCCC”.

Further, in correspondence with the file name in the file name column 9, the thread ID of the thread using this file is shown in the thread information column 11. For example,
The thread ID column 12 for the file name "AAAA"
Thread ID “ID1”, thread ID “ID4”,
The thread IDs “ID12” and ... Are the file names “B
For "BB", enter the thread ID in the thread ID column 13.
"ID3", thread ID "ID8" and so on are shown in the thread ID column 13 for the file name "CCCCC", and thread ID "ID15" and so on are shown as threads using each file. There is.

Next, an operation example of one embodiment will be described with reference to FIGS. As a premise, the operation instruction to the file opening means 3, the operation instruction to the file closing means 4, and the operation instruction to the data writing means 5 from the thread instruction unit 1 by each thread are performed asynchronously. Each operation will be described below in order.

<Operation of File Opening Means 3> For example, it is assumed that the thread having the thread ID “ID15” passes the thread ID “ID15” and the file name “CCCCC” from the thread instruction unit 1 to the file opening means 3. The file open means 3 uses the file name “CCC
In order to open the file "CC", the thread ID "ID15" and the file name "CCCCC" are transferred to the file opening / closing exclusive control means 6.

As a result, the file opening / closing exclusive control means 6
References / updates the file information holding unit 8. At this time, when a plurality of threads simultaneously access the file information holding unit 8 via the file opening / closing exclusive control unit 6, the information for each thread stored in the file information holding unit 8 is destroyed, or during rewriting. Incorrect information for each thread is referenced.

Therefore, when referring / updating the information for each thread to the file information holding unit 8, a mutex (always gives access right to one thread) is used to access the file information holding unit 8. Synchronize with the access of each thread.

When the thread having the thread ID “ID15” acquires the ownership of the mutex, the opening / closing exclusive control means 6 determines the file name column 9 of the file information holding unit 8.
Of the received file name "CCCC
It is searched whether or not there is the same file name as "C".

At this time, if the received file name "CCCCC" does not exist in the file name column 9, the open / close exclusive control means 6 additionally writes the received file name "CCCCC" in the file name column 9 to obtain the file name. "CCC
File 2 corresponding to "CC" is opened.

Then, the opening / closing exclusive control means 6 uses the file handle "ZZ" corresponding to the file name "CCCCC".
“Z” is acquired, and this file handle “ZZZ” is written in the file handle column 10 corresponding to the added file name “CCCCC”. Further, the opening / closing exclusive control unit 6 writes the received thread ID “ID15” in the thread ID column 14 of the thread information column 11.

Next, the opening / closing exclusive control means 6 outputs the obtained file handle “ZZZ” to the file opening means 3. Then, the file open means 3 receives the file handle “ZZ input from the open / close exclusive control means 6.
Z ”is output to the thread with the thread ID“ ID15 ”. As a result, the thread with the thread ID “ID15” confirms that the file with the file name “CCCCC” has been opened by inputting the file handle “ZZZ”.

On the other hand, when the received file name “CCCCC” exists in the file name column 9, the open / close exclusive control means 6 additionally writes the thread ID “ID15” in the thread ID column 14 of the per thread information column 11. As a result, the opening / closing exclusive control means 6 obtains the file handle “ZZZ” corresponding to the file name “CCCCC” from the file handle column 10 and the file handle “ZZ”.
Z ”is output to the file opening means 3.

Then, the file open means 3 receives the file handle "ZZ input from the open / close exclusive control means 6."
Z ”is output to the thread with the thread ID“ ID15 ”. As a result, the thread with the thread ID “ID15” confirms that the file with the file name “CCCCC” is opened by inputting the file handle “ZZZ”.

<Operation of File Closing Unit 4> For example, it is assumed that the thread with the thread ID “ID3” passes the thread ID “ID3” and the file handle “YYY” from the thread instruction unit 1 to the file closing unit 4. This file handle “YYY” is acquired by the thread with the thread ID “ID3” in the operation of the file opening means 3 when the file with the file name “BBB” is opened.

The file means close 4 transfers the thread ID "ID3" and the file handle "YYY" to the file opening / closing exclusive control means 6 in order to close the file with the file handle "YYY".

At this time, the file opening / closing exclusive control means 6
Waits until the thread with the thread ID “ID3” acquires ownership of the mutex. Next, the file opening / closing exclusive control means 6 acquires the ownership of the mutex.

Then, the file opening / closing exclusive control means 6 is
File handle column 10 in the file information holding unit 8
See the list. At this time, the file opening / closing exclusive control unit 6 searches for a file handle that matches the received file handle “YYY”.

Next, when the file opening / closing exclusive control means 6 detects the matching file handle "YYY", the file handle "Y" is displayed in the thread information column 11.
The thread ID column 13 corresponding to “YY” is referred to. Then, the file opening / closing exclusive control unit 6 searches for a thread ID line that matches the received thread ID “ID3”. At this time, the file open / close exclusive control unit 6 deletes the thread ID “ID3” from the thread ID column 13 when detecting the thread ID “ID3”.

Then, the file opening / closing exclusive control means 6 is
The thread ID “ID3” is displayed in the list in the thread ID column 14.
If there is no thread ID of another thread in the thread ID column 14 after the removal of the, the file handle “YYY” in the file handle column 10 of the file information holding unit 8
To delete. Next, the file opening / closing exclusive control means 6 closes the file 2 based on the file handle “YYY”.

On the other hand, the file opening / closing control means 6 removes the thread ID “ID3” from the list in the thread ID column 14 and then the thread ID “ID8” of another thread in the thread ID column 14, so the file 2 The file handle “YYY” is output to the file closing means 4 without closing the file.

Then, the file closing means 4 outputs the file handle "YYY" input from the file opening / closing control means 6 to the thread of thread "ID3". As a result, the thread with the thread “ID3” recognizes that the file closing means 4 has performed the closing operation corresponding to the instruction.

<Operation of Data Writing Unit 5> For example, the thread having the thread ID “ID3” is the thread instruction unit 1
From thread ID “ID3”, file handle “Y
It is assumed that the data D to be written in the file of "YY" and the file name "BBB" is output to the data writing means 5. The data writing unit 5 transfers the thread D “ID3”, the file handle “YYY”, and the data D to the file writing exclusive control unit 7 in order to write the data D in the file indicated by the file handle “YYY”.

Since the file write exclusive control means 7 performs additional writing to the file indicated by the file handle "YYY", for example, file 2, when a plurality of threads access the file 2 at the same time, the data stored in the file 2 is written. Will be destroyed.

Therefore, the file write exclusive control means 7
When updating the data stored in the file 2, the mutex is used to synchronize the data updating operation of the threads with respect to the file 2. That is, the plurality of threads are prevented from simultaneously performing the data update operation on the file 2.

File write exclusive control means 7
Performs additional writing to the end of the file 2 (the end of the currently stored data) of the data D input from the thread that has acquired the ownership of the mutech, for example, the thread with the thread ID “ID3”. Next, the file write exclusive control means 7 outputs the file handle “YYY” to the data writing means 5 when the additional writing is completed.

Then, the data writing means 5 outputs the file handle "YYY" input from the file write exclusion control means 7 to the thread having the thread ID "ID3". As a result, the thread with the thread ID “ID3” confirms that the data writing unit 5 has performed the writing operation corresponding to the instruction.

Next, the effect of this embodiment will be described. In the file writing method in the multi-thread program of this embodiment, the interval at which exclusive control is performed is
Only while the file open / close exclusive control unit 6 is referring to / updating the file information holding unit 8 and while the file write exclusive control unit 7 is additionally writing data to the file 2, Since the time is shorter than the interval from the opening to the closing, the CPU usage efficiency by the thread parallel operation can be improved.

Further, in the file writing method in the multi-thread program of this embodiment, when the file opening / closing exclusive control means 6 returns the file handle of an already opened file, the file is opened. You don't have to open it,
Since the number of times the file is opened can be reduced, it is possible to improve the CPU usage efficiency by the thread parallel operation.

Further, in the file writing method in the multi-thread program of the present embodiment, when the number of threads using the file indicated by the same file handle is two or more, a thread closes the file. Even if it goes, if there are other threads using this file, the file is not closed, so the number of times the file is closed can be reduced, so that it is possible to improve the CPU usage efficiency by the thread parallel operation.

Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes within the scope not departing from the gist of the present invention. Even so, it is included in the present invention.

[0052]

The file name of the opened file, the file handle indicating the file, and the thread ID indicating the thread using the file
And a file information holding unit that stores a table indicating the relationship between the thread name, a file name of a file that is opened under the control of the thread, and a file opening unit that outputs a thread ID indicating the thread, and a thread that controls the thread. When the thread ID for identifying the thread and the file name of the file to be opened are input from the file opening means, the file closing means for outputting the thread ID and the file handle corresponding to the file to be closed, and the file corresponding to the file Acquires a file handle, stores this file handle in the file information holding unit in association with this thread ID and this file name, and supports the thread ID for identifying the thread from the file closing means and the file to be closed. File opening / closing exclusive control means for removing this file handle, the file name corresponding to this file handle, and the thread ID from the file information holding unit when the file handle is input, and the thread ID indicating this thread under the control of the thread. , A file handle indicating a file to be written, data writing means for outputting data to be written in the file, and a thread I input from the data writing means
D, a file handle, and file write exclusive control means for receiving the data to be written in the file and writing this data at the end of the file corresponding to this file handle, so that the interval at which exclusive control is performed holds the file information. Since it is only between the reference / update to the part and the additional write to the file, the time is shorter than the time between opening and closing the file. When performing additional writing to a certain file, it is possible to improve the CPU usage efficiency by the thread parallel operation.

Further, according to the present invention, the file open / close exclusive control means returns the file handle of the file when the file already opened exists.
There is no need to open the file, the number of times the file is opened is reduced, and the number of threads using the file indicated by the same file handle is 2
If one thread performs a file close operation when there are more than two files, the file will not be closed if there are other threads that are using this file. It can be shortened.

[Brief description of drawings]

FIG. 1 illustrates a multi-threaded thread according to an embodiment of the present invention.
It is a block diagram which shows the structure of the file writing system in a program.

FIG. 2 is a conceptual diagram showing a data structure of a file information holding unit 8 in FIG.

[Explanation of symbols]

1 Thread instruction part 2 files 3 File open means 4 File closing means 5 Data writing means 6 File open / close exclusive control means 7 File write exclusive control means 8 File information storage 9 File name column 10 File handle column 11 Thread information field 12, 13, 14 Thread ID column

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Claims (4)

(57) [Claims] 1. In a file writing method in a multi-thread program including a plurality of threads, a file name of an open file, a file handle indicating the file, and the thread using the file A file information holding unit that stores a table that shows the relationship with the thread ID that indicates the thread, a file name of a file that is opened under the control of the thread, and a file opening unit that outputs the thread ID that indicates this thread, and the thread control By the file closing means for outputting the thread ID indicating this thread and the file handle corresponding to the file to be closed, and when the thread ID for identifying the thread and the file name of the file to be opened are input from the file opening means, The file handle corresponding to a file is acquired, the file handle is stored in the file information holding unit in association with the thread ID and the file name, and the thread ID for identifying the thread from the file closing unit and the file to be closed When a file handle corresponding to is input, this file handle, a file name corresponding to this file handle, and a file open / close exclusive control means for removing the thread ID from the file information holding unit, and this thread is indicated by the control of the thread. A thread ID, a file handle indicating a file to be written, and data writing means for outputting data to be written to this file; and a thread ID, a file handle and data to be written to the file, which are input from the data writing means. Receiving, file additional writing method in a multi-threaded program that the end of the file corresponding to the file handle, characterized by comprising a file write exclusive control means for writing the data. 2. The file opening / closing exclusive control means refers to / updates the file name in the file information holding unit in which the file name is written, and refers to the thread ID and the thread ID stored in the file information holding unit. The additional file writing method in the multi-thread program according to claim 1, wherein exclusive control is performed based on a file handle to control opening and closing of the file. 3. The file opening / closing exclusive control unit receives the thread ID and the file name from the file opening unit, refers to the file information holding unit, and detects that this file name is not in the file information holding unit.
When the file corresponding to this file name is opened, the file handle and the information for each thread are stored in the file information holding unit and a file handle is returned, and it is detected that the file name of this file name exists in the file information holding unit, File I is not processed and thread I
D is stored in the file information holding unit, a file handle is output to the file opening unit, and when the thread ID and the file handle are received from the file closing unit, the thread is referred to by referring to the file information holding unit. If the ID is deleted and no other thread ID exists, the file is closed, the file handle is output to the file closing means, and if no other thread ID exists, the file handle is closed without closing the file. The file additional writing method in the multi-thread program according to claim 1 or 2, wherein the file is output to a file closing means. 4. The file write exclusive control means writes the data to the file of the thread other than the thread that has opened the file, the thread ID and the thread ID stored in the file information holding unit. The file additional writing method in the multi-thread program according to any one of claims 1 to 3, wherein exclusive control is performed based on a file handle.