JP2009251871A - Contention analysis device, contention analysis method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contention analysis device, a contention analysis method, and a program, which are suitable for analyzing whether the state of access contention for a shared resource is normal or not. <P>SOLUTION: Control units 110A-110N execute an analysis target program including an instruction for exclusively making access to a shared resource. Meanwhile, the control unit 110X acquires an access right (lock) for the shared resource accessed by the analysis target program, and measures a lock acquisition required time required for acquiring the lock. Further, the control unit 110X stores nearest preceding lock acquisition required time by a predetermined number, and on the basis of the stored lock acquisition required time, calculates an allowable range for allowing as the lock acquisition required time. If a latest lock acquisition required time is within the allowable range, the control unit 110X analyzes the state of access contention for a shared resource as being normal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  A contention analysis apparatus, contention analysis method, and program suitable for analyzing whether the state of access contention for a shared resource is normal or not

  Multitask systems and multiprocessor systems that perform data processing by sharing resources such as memory and files are known. In a multitask system, a plurality of tasks (including processes and threads executed in the same process) are controlled to be processed by one CPU (Central Processing Unit) in a time division manner. The process is controlled so as to be distributed to a plurality of CPUs (processors) and executed in parallel. A multiprocessor system in which each of the CPUs operates as a multitask system is also known.

  In either case, the process (similar to threads instead of processes, but for ease of understanding, here we will describe the process) is a critical section of shared resources (ie, for one shared resource). When multiple processes are performed at the same time, it is necessary to acquire a lock, that is, an exclusive access right to prevent access by other processes when accessing a portion that cannot maintain consistency. . When the access to the shared resource is completed, the process releases the lock and transfers the access right to another process.

However, when intense contention for lock acquisition occurs, the percentage of time that other processes wait for lock release increases, and processing efficiency decreases. For this reason, in order to access shared resources more efficiently, a technique for obtaining the time required to execute an instruction in the exclusive control section has been proposed. Such a technique is disclosed in the following documents, for example.
Japanese Patent Laid-Open No. 5-66972

  In the technique disclosed in Patent Document 1, a trace file, that is, a file storing information of instructions executed in an operation program is analyzed to extract an exclusive control section, and an average instruction execution time of the exclusive control section is calculated. .

  However, since the timing of access to the shared resource changes each time depending on the environment at the time of execution, just using the trace file obtained by executing the program once as in Patent Document 1, severe competition of the shared resource It is not always possible to detect an abnormality such as a state or a situation in which two or more tasks are waiting for the release of resources occupied by each other (ie, deadlock).

  Also, based on the recorded time, in order to determine whether there is a conflict within the expected range, or whether an abnormal state such as an illegal lock remaining state or deadlock state has occurred. Therefore, it is necessary to determine a determination criterion for determining an abnormality. However, the usage status of resources exclusively controlled by locks is generally not uniform, and therefore the time required for actual acquisition after a lock acquisition request is not uniform. For this reason, for example, even in a case where it takes time to acquire the lock because another process in the computer uses many CPUs, there is a possibility that it is erroneously determined that an abnormality has occurred.

  The present invention is to solve the above-described problems, and provides a contention analysis apparatus, contention analysis method, and program suitable for analyzing whether or not the state of access contention for a shared resource is normal. With the goal.

In order to achieve the above object, a competitive analysis apparatus according to the first aspect of the present invention provides:
A contention analysis device that analyzes whether or not the access contention status for a shared resource is normal,
A plurality of execution units that exclusively execute access to the shared resource while competing with each other according to an analysis target program including an instruction to exclusively access the shared resource;
An access right acquisition unit for acquiring an access right for exclusive access to the shared resource;
A measuring unit for measuring the time required for the access right acquisition unit to acquire the access right;
An accumulating unit for accumulating a predetermined number of acquisition times of the measured access right;
A calculation unit that calculates an allowable range allowed as the access right acquisition time based on the accumulated number of access right acquisition times stored;
When the measured latest access right acquisition time is included in the allowable range, it is analyzed that the state of access conflict for the shared resource is normal, and the measured latest access right acquisition time is within the allowable range. If not included, the analysis unit analyzes that the state of access conflict to the shared resource is abnormal,
Comprising
It is characterized by that.

In addition, a competitive analysis method according to another aspect of the present invention includes:
A contention analysis method for analyzing whether the state of access contention for a shared resource is normal,
An execution step of executing exclusive access to the shared resource while competing according to the analysis target program including an instruction to exclusively access the shared resource;
An access right acquisition step of acquiring an access right for exclusive access to the shared resource;
In the access right acquisition step, a measurement step for measuring a time required to acquire the access right,
An accumulating step for accumulating a predetermined number of acquisition times of the measured access right;
A calculation step of calculating an allowable range allowed as the access right acquisition time based on the accumulated predetermined number of access right acquisition times;
When the measured latest access right acquisition time is included in the allowable range, it is analyzed that the state of access conflict for the shared resource is normal, and the measured latest access right acquisition time is within the allowable range. If not, an analysis step for analyzing that the state of contention for access to the shared resource is abnormal;
It is characterized by providing.

A program according to another aspect of the present invention is as follows:
Computer
A program that functions as a contention analysis device that analyzes whether the state of access contention for a shared resource is normal,
Computer
A plurality of execution units that exclusively execute access to the shared resource while competing with each other according to an analysis target program including an instruction to exclusively access the shared resource;
An access right acquisition unit for acquiring an access right for exclusive access to the shared resource;
A measuring unit for measuring the time required for the access right acquisition unit to acquire the access right;
An accumulating unit for accumulating a predetermined number of acquisition times of the measured access right;
A calculation unit that calculates an allowable range allowed as the access right acquisition time based on the accumulated number of access right acquisition times stored;
When the measured latest access right acquisition time is included in the allowable range, it is analyzed that the state of access conflict for the shared resource is normal, and the measured latest access right acquisition time is within the allowable range. If not included, the analysis unit analyzes that the state of access conflict to the shared resource is abnormal,
It is made to function as.

  According to the present invention, it is possible to provide a contention analysis device, a contention analysis method, and a program suitable for analyzing whether or not the state of access contention for a shared resource is normal.

(Embodiment)
Hereinafter, a schematic configuration of the competition analysis apparatus 100 according to the present embodiment will be described.

  The competition analysis apparatus 100 according to the present embodiment is a multiprocessor system including a plurality of control units 110 and a main memory 120 as shown in FIG. When the contention analysis apparatus 100 executes a program for accessing the main memory, which is a shared resource, on the plurality of control units 110, is the access contention state for the shared resource caused by the execution of the program normal? Or analyze whether it is abnormal.

Each of the plurality of control units 110 includes a CPU (Central Processing Unit) 111, a cache memory 112, and the like.
Here, the cache memory 112 is a volatile memory that operates at a high speed, although it has a smaller capacity than the main memory 120 described later, and a copy of the information stored in the main memory 120 is consistent with the main memory 120. However, various processes are executed at high speed by appropriately storing and reducing the number of times the CPU 111 accesses the main memory 120. Each CPU 111 of the control unit 110 performs processing according to a program stored in the cache memory 112.

  The main memory 120 is configured by a volatile memory, and functions as a shared resource that is shared and used by the plurality of control units 110.

  In the present embodiment, an analysis target program that accesses a shared resource is executed on the control units 110A to 110N (N means an arbitrary number), and a competition analysis is performed on the control unit 110X. Run the application. Thereby, the control unit 110X performs an analysis process of the analysis target program. At this time, the control unit 110X is preferably a control unit different from the control units 110A to 110N.

  Therefore, in the present embodiment, the CPU 111 of the control unit 110X functions as an access right acquisition unit, a calculation unit, and an analysis unit, which will be described later. Further, a clock (not shown) configured by an oscillation circuit or the like included in the CPU 111 of the control unit 110X functions as a measurement unit described later. The cache memory 112 of the control unit 110X functions as a storage unit described later in addition to storing the competition analysis application.

  Here, as shown in FIG. 2, the storage unit starts the access right acquisition process (start time) for each access right defined for each shared resource defined in the analysis target program, It has a configuration for storing the time (end time) at which the acquisition process was successful and the time required for the acquisition process (lock acquisition required time: end time-start time) for the latest M items (M: a predetermined integer). . In the present embodiment, the exclusive access right is hereinafter referred to as lock.

  On the other hand, the analysis target program is stored in the cache memory 112 of the control units 110A to 110N that execute the analysis target program, and each of the CPUs 111 functions as an execution unit by executing the analysis target program. However, the control units that function as execution units and the number thereof change depending on the contents of the analysis target program.

(Competitive analysis process)
The operation of the conflict analysis apparatus 100 having the above configuration will be described with reference to FIG. At this time, it is assumed that the competition analysis application is already started in the control unit 110X, and the analysis target program is already started in the control units 110A to 110N.

  First, the control unit 110X stores, as the current time, the time at which the contention analysis process was last started (referred to as the final execution time) (step S201). Next, it is determined whether a predetermined time (for example, T time) has elapsed from the last execution time (step S202). If the time T has not elapsed, the process returns to step S202. On the other hand, when T time has passed (step S202; Y), the subsequent processing is executed and analysis processing of the analysis target program is started. That is, the control unit 110N executes Steps S203 to S211 described below for each of the locks on the shared resource accessed by executing the analysis target program every T time.

  First, the control unit 110X stores the current time in the corresponding area of the storage unit as the time (start time) at which the lock acquisition process is started (step S203). Next, the control unit 110X acquires the lock (step S204). That is, the CPU 111 of the control unit 110X functions as an access right acquisition unit.

  Here, the control unit 110X acquires a lock using the same method as that of the analysis target program. For example, a case where the source program shown in FIG.

  When the analysis target program shown in FIG. 4 is executed, as shown in FIG. 5, the process P0 in charge of initialization (process executed by specifying “-init”) and the other process P1 (designation of arguments) The process executed without the process acquires the lock realized in the shared memory, and repeats the process of exclusive access to the critical section (the part shown in (A)) (1000 in FIG. 4, line 45). Times). The program is written in C language, and operates by calling a system call provided by a system V OS (Operating System).

Any of the above processes allocates shared memory (FIG. 4, line 21), and allocates (attaches) the allocated shared memory segment to the address space of its own process (FIG. 4, line 33). Then, an acquisition process is performed for the lock in the attached memory space (FIG. 4, line 46). When the lock is acquired, the critical section is accessed (FIG. 4, line 47), and the lock is released (FIG. 4, line 48).
In addition, the process P0 also performs processing such as creation of shared memory (FIG. 4, line 21) and lock initialization (FIG. 4, lines 40 to 43, etc.).

  The control unit 110X also issues a command similar to the command described in the analysis target program and executes lock acquisition processing. That is, in the example of FIG. 4, the control unit 110X assigns a shared memory with the path name “sample” and the project ID “A” as in line 21, and allocates the shared memory as in line 33. To the address space and acquire the lock in the same manner as the 46th line.

  The instruction to acquire the lock is registered in advance in a predetermined file (hereinafter referred to as a lock attribute file) based on the analysis target program, and is read into the cache 112 of the control unit 110X. Remember it. FIG. 7B shows an example of the lock attribute file. As shown in FIG. 7B, the lock attribute file describes a series of definitions and processes necessary for acquiring the lock. Based on the information registered in the lock attribute file, the control unit 110X defines variables necessary for issuing a lock acquisition command, and lock acquisition commands registered in the lock family definition file every T time. Execute.

  When the lock acquisition is successful, the control unit 110X uses the current time as the end time, measures the lock acquisition time required for acquiring the lock (that is, from the start time stored in step S203 to the time when the lock acquisition ends). Measurement) (step S205). That is, the CPU 111 of the control unit 110X functions as a measurement unit. Then, the end time and the required lock acquisition time are stored in the corresponding areas of the storage unit (step S206), and the lock is immediately released (step S207). Here, the lock release command is registered in the lock attribute file in the same manner as the lock acquisition command, and the control unit 110X reads the lock release command from the lock attribute file and releases the lock.

  In the present embodiment, the program described in C language that exclusively accesses the critical section by calling the system V system call as described above has been described as an analysis target. Good. That is, even if the program is written in a language other than the C language, or is a program using a system call other than the system V system, as long as the program explicitly performs exclusive control, It is possible to analyze the state of access contention in the manner described.

  Next, the control unit 110X obtains the latest predetermined number (for example, M-1 cases excluding the latest value) of locks currently being processed from the storage unit, and acquires these M-1 cases. Based on the required lock acquisition time, the normal value range as the lock acquisition required time is calculated (step S208). Thus, the CPU 111 of the control unit 110X functions as a calculation unit.

  At this time, as a normal value, for example, a statistically acceptable range (for example, an average value ± standard deviation × 2, etc. for the latest M-1 lock acquisition time periods) is obtained. When the accumulated lock acquisition time is less than the predetermined number, the predetermined lower limit value and the upper limit value are used as the normal value range. Alternatively, the processes in steps S208 to S211 may be skipped until a predetermined number of lock acquisition times are accumulated.

  Next, the control unit 110X determines whether or not the latest lock acquisition required time of the currently processed lock obtained in step S205 is within the normal value range obtained in step S208 (step S209). . If it is within the range (step S209; Y), the control unit 110X assumes that the time required for acquiring the latest one lock is average, and the contention for the shared resource managed by the lock is normal. Is analyzed (step S210). On the other hand, when the time required for acquiring the latest lock is out of the normal range (step S209; N), the control unit 110X indicates that the contention for the shared resource managed by the lock is abnormal. It is analyzed that there is (step S211). Thus, the CPU 111 of the control unit 110X functions as an analysis unit.

  When the above process is completed, the process returns to step S201, and when the predetermined time T has elapsed, the processes of steps S203 to S211 described above are performed again for all locks.

  As described above, the embodiment according to the present invention dynamically analyzes the contention state of a certain critical section, and statistically locks from the accumulated past lock acquisition time without using a fixed criterion. Analyze whether there is an abnormality in the acquisition process. Since the access status to the critical section is not uniform, it is possible to detect an abnormality flexibly according to the status by not using a fixed reference.

  In addition, the embodiment according to the present invention is not limited to a lock mechanism that performs atomic setting / reset of lock variables. For example, a daemon process for exclusive control management has a specific shared resource (critical It can also be applied to a locking mechanism that centrally manages access to (section). For example, in order to access a shared resource, if there is a lock mechanism that specifies the port number of the exclusive control management daemon and sends a lock acquisition request, the lock attribute file contains the port number of the daemon The data structure to be delivered and its value, the data structure returned upon success or failure, its value, etc. may be stored in association with each other. Then, the control unit 110X may execute acquisition of a lock based on the contents registered in the lock attribute file.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, A various deformation | transformation and application are possible. Moreover, it is also possible to freely combine the constituent elements of the above-described embodiments.

  For example, in the above embodiment, after determining whether or not the contention state is normal (steps S210 and S211), the analysis result is displayed in the log file along with the lock acquisition time and the range calculated as the normal value. Or the like. Furthermore, when analyzing that the race condition is abnormal (step S211), a dialog box or the like is displayed, and information similar to the information output to the log file is output to a display unit (not shown) including a monitor or the like. Then, the user may be notified. At this time, the user may be able to select and input whether or not to interrupt the process. As described above, the CPU 111 of the control unit 110X may function as the output unit illustrated in FIG.

  In the above embodiment, if the lock being acquired in step S204 is in a deadlock state, step S204 does not end. In order to avoid this, the control unit 110X ends the lock acquisition process when the current time has passed a predetermined time T2 from the start time recorded in step S203 after executing step S204. You may make it do.

  That is, for example, the control unit 110X periodically interrupts the lock acquisition process, and determines whether the current time is longer than the predetermined time T2 from the start time recorded in step S203. If the time longer than the predetermined time T2 has elapsed, the lock acquisition process may be terminated. On the other hand, if the predetermined time T2 has not yet elapsed, the lock acquisition process may be resumed.

  As described above, when the predetermined time T2 has elapsed without being able to acquire the lock, it is analyzed that the deadlock has occurred, and the control unit 110X may advance the conflict analysis process to step S211. Further, since the latest start time recorded in the immediately preceding step S203 is not used thereafter, it may be deleted.

  In addition, when a predetermined time T2 has passed without acquiring a lock, when outputting the analysis result to the log file, it may be output that there is a possibility of deadlock instead of the lock acquisition required time. Good.

  In the above embodiment, the lock acquisition command executed by the control unit 110X is registered in the lock attribute file or the like based on the analysis target program and stored in the main memory 120 or the like. Instead, as shown in FIG. 6, the control unit 110X may include an access right information extraction unit so that the lock attribute file is automatically extracted from the analysis target program.

  For example, basic information about a system call related to lock called in a program is registered in a predetermined file in advance (this file is hereinafter referred to as a lock basic information file). The CPU 111 of the control unit 110X functioning as the access right information extracting unit refers to the lock basic information file and applies the existing syntax analysis method, semantic analysis method, etc. to the analysis target program to acquire the lock. What is necessary is just to extract a series of instructions required for.

  FIG. 7A shows an example of the lock basic information file when the program of FIG. 4 is the analysis target. In the lock basic information file, for example, information such as a program description language, an OS type, a lock acquisition instruction, a lock release instruction, a shared memory allocation instruction, a shared memory space attach instruction, and a shared memory detach instruction are described. To do.

  The control unit 110X refers to the lock acquisition command described in the lock basic information file and analyzes the source file, so that the 46th line of the source file: “pthread_mutex_lock (& shmptr-> mutex);” acquires the lock. Identify the location that you are doing. Further, the control unit 110X determines that the structure shmptr used to acquire the lock is defined in the seventh line: “typedef struct shared_mem”, and the 33rd line: “shmat (shmid, 0,0)”. And specify that the value is assigned.

  The control unit 110X refers to the lock basic information file, and the “shmat” system call attaches the shared memory segment specified by the first argument to the address space of the calling process (ie, the space pointed to by shmptr). Is identified.

  In addition, the control unit 110X has an int type variable, shmid, which is the first argument of the shmat system call, line 21: "shmget (ftok (" sample ", 'A'), sizeof (shared_mem), IPC_CREAT)" And specify that the value is assigned. The control unit 110X refers to the lock basic information file so that "ftok (" sample ", 'A')", which is the first argument of shmget, generates a shared memory key, and shmget Specify the generated key to specify that a shared memory segment is to be allocated.

As described above, the control unit 110X extracts the lock acquisition command described in the lock basic information file from the source file, and first specifies a value to be used as an argument of the lock acquisition command. Then, a process necessary for obtaining a value used as the argument is acquired while sequentially referring to the lock basic information file. The information acquired as described above is output, for example, as a lock attribute file as shown in FIG.
If a program that uses the same system call is an analysis target, the lock basic information file can be reused.

  In the above embodiment, the competition analysis apparatus 100 has been described as having various operation programs stored in advance in a cache memory or the like. However, a program for executing the above processing operations is stored and distributed on a computer-readable recording medium such as a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), and an MO (Magneto-Optical disk). A device that executes the above-described processing operation may be configured by installing the program in a computer.

  Further, the computer may include a communication unit having a communication interface or the like. The program may be stored in a disk device or the like included in a predetermined server device on a communication network such as the Internet, and may be superimposed on a carrier wave and downloaded to a computer via a communication unit. Furthermore, the above-described processing can also be achieved by starting and executing a program while transferring it via a communication network.

  In addition, when the functions described above are realized by sharing the OS, or when the functions are realized by cooperation between the OS and the application, only the part other than the OS may be stored in the medium and distributed. It may be downloaded to a computer.

  Moreover, the competition analysis apparatus 100 according to the above embodiment can also be realized by dedicated hardware.

It is a block diagram which shows schematic structure of the competition analyzer which concerns on this Embodiment. It is a figure which shows the structural example of the storage part which concerns on this Embodiment. It is a flowchart which shows the example of the competition analysis process which concerns on this Embodiment. It is a figure which shows the example of the analysis object program which concerns on this Embodiment. It is a figure explaining operation | movement of the program of FIG. It is a figure which shows one of the modifications of this Embodiment. (A) is a figure which shows the example of the lock basic information file utilized in one of the modifications of this Embodiment, (B) shows the example of the lock attribute file obtained based on the lock basic information file FIG.

Explanation of symbols

100 competition analyzer 110 control unit 111 CPU
112 Cache memory 120 Main memory

Claims (6)

A contention analysis device that analyzes whether or not the access contention status for a shared resource is normal,
A plurality of execution units that exclusively execute access to the shared resource while competing with each other according to an analysis target program including an instruction to exclusively access the shared resource;
An access right acquisition unit for acquiring an access right for exclusive access to the shared resource;
A measuring unit for measuring the time required for the access right acquisition unit to acquire the access right;
An accumulating unit for accumulating a predetermined number of acquisition times of the measured access right;
A calculation unit that calculates an allowable range allowed as the access right acquisition time based on the accumulated number of access right acquisition times stored;
When the measured latest access right acquisition time is included in the allowable range, it is analyzed that the state of access conflict for the shared resource is normal, and the measured latest access right acquisition time is within the allowable range. If not included, the analysis unit analyzes that the state of access conflict to the shared resource is abnormal,
Comprising
Competitive analysis device characterized by that. The competition analysis apparatus according to claim 1,
Further comprising an access right information extraction unit that analyzes a source code of the analysis target program and extracts an access right acquisition instruction for acquiring an access right to the shared resource, which is defined in the program;
The access right acquisition unit acquires an access right based on the extracted access right acquisition command.
Competitive analysis device characterized by that. The competition analysis apparatus according to claim 1,
An output unit that outputs at least one of outputting the analysis result to a log file or outputting a display screen to notify a user;
Competitive analysis device characterized by that. The competition analysis apparatus according to claim 1,
The access right acquisition unit stops acquiring the access right when a predetermined time or more has elapsed since the start of the acquisition of the access right;
Competitive analysis device characterized by that. A contention analysis method for analyzing whether the state of access contention for a shared resource is normal,
An execution step of executing exclusive access to the shared resource while competing according to the analysis target program including an instruction to exclusively access the shared resource;
An access right acquisition step of acquiring an access right for exclusive access to the shared resource;
In the access right acquisition step, a measurement step for measuring a time required to acquire the access right,
An accumulating step for accumulating a predetermined number of acquisition times of the measured access right;
A calculation step of calculating an allowable range allowed as the access right acquisition time based on the accumulated predetermined number of access right acquisition times;
When the measured latest access right acquisition time is included in the allowable range, it is analyzed that the state of access conflict for the shared resource is normal, and the measured latest access right acquisition time is within the allowable range. If not, an analysis step for analyzing that the state of contention for access to the shared resource is abnormal;
A competitive analysis method characterized by comprising: Computer
A program that functions as a contention analysis device that analyzes whether the state of access contention for a shared resource is normal,
Computer
A plurality of execution units that exclusively execute access to the shared resource while competing with each other according to an analysis target program including an instruction to exclusively access the shared resource;
An access right acquisition unit for acquiring an access right for exclusive access to the shared resource;
A measuring unit for measuring the time required for the access right acquisition unit to acquire the access right;
An accumulating unit for accumulating a predetermined number of acquisition times of the measured access right;
A calculation unit that calculates an allowable range allowed as the access right acquisition time based on the accumulated number of access right acquisition times stored;
When the measured latest access right acquisition time is included in the allowable range, it is analyzed that the state of access conflict for the shared resource is normal, and the measured latest access right acquisition time is within the allowable range. If not included, the analysis unit analyzes that the state of access conflict to the shared resource is abnormal,
A program characterized by functioning as

Images