INFORMATION PROCESSING DEVICE

Description

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is based on and claims the benefits of priority of Japanese Patent Application No. 2018-068431 filed on March 30, 2018.TECHNICAL FIELD

[0002] The present disclosure relates to an information processing apparatus including a thread scheduler that allocates a process to multiple process execution hardware that process a program having a graph structure.BACKGROUND ART

[0003] As an invention for ensuring a functional safety of processing elements that are multiple process execution hardware, an invention shown in JP 2015 - 153 282 A described below has been disclosed. In JP 2015 - 153 282 A described below, a system is built by a safety concept that issuing the same processes to the process execution hardware for observing the output difference between them (known as software lockstep), and a bus interface unit is employed. The bus interface unit monitors requests issued by the process execution hardware. If there is a mismatch between them, the unit processes a procedure for handling the error causing the mismatch. Otherwise, the unit does regular operations.

[0004] Moreover, US 2012 0 210 164 A1 discloses a system for scheduling threads in a multiprocessing system with selective pairing of processor cores for increased processing reliability, wherein a selective pairing facility is provided that selectively connects (pairs) multiple microprocessor or processor cores to provide one highly reliable thread.SUMMARY OF INVENTION

[0005] A requirement of a functional safety is a confirmation of whether there is a hardware failure. In the confirmation, a different hardware resource performs a duplicate execution on a process, and results are compared. In the duplicate execution, changing an execution timing and an execution hardware resource is a requirement for a failure detection. Conventionally, the same software is executed for multiple process execution hardware having the same configuration.

[0006] However, since a premise of the conventional failure detection is that the process execution hardware is duplicated, there is a limit to a compact configuration of a process execution hardware.

[0007] It is an object of the present disclosure to implement a failure detection of a process execution hardware without duplication of hardware. The object is solved by the subject matter of the independent claim. Further embodiments are disclosed in the subclaims.

[0008] According to the present disclosure, an information processing apparatus includes a thread scheduler that allocates a process to multiple process execution hardware that process a program having a graph structure. The information processing apparatus includes a code reader (141) that reads a diagnostic code stored in advance and an allocator (142) that causes the multiple process execution hardware to execute the diagnostic code so as to complete diagnosis within a mean time to failure.

[0009] Since the multiple process execution hardware are caused to execute the diagnostic code so as to complete the diagnosis within the mean time to failure, it may be possible to perform failure diagnosis using the process execution hardware already placed for processing without duplicating hardware for the failure diagnosis.BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 is a diagram illustrating parallel processing that is a premise of the present embodiment; FIG. 2 is a diagram showing a system configuration example for executing the parallel processing shown in FIG. 1; FIG. 3 is a diagram showing a configuration example of a DFP used in FIG. 2; FIG. 4 is a diagram illustrating one aspect that executes a diagnostic code in the present embodiment; FIG. 5 is a diagram illustrating one aspect that executes the diagnostic code in the present embodiment; FIG. 6 is a diagram illustrating one aspect that executes the diagnostic code in the present embodiment; FIG. 7 is a diagram illustrating one aspect that executes the diagnostic code in the present embodiment; and FIG. 8 is a diagram illustrating one aspect that executes the diagnostic code in the present embodiment. DESCRIPTION OF EMBODIMENTS

[0011] Hereinafter, the present embodiment will be described with reference to the attached drawings. In order to facilitate the ease of understanding, the same reference numerals are attached to the same configuration elements in each drawing where possible, and redundant explanations are omitted.

[0012] FIG. 1(A) shows a program code having a graph structure. FIG. 1(B) shows a thread state. FIG. 1(C) is a situation of parallel processing.

[0013] As shown in FIG. 1(A), in the present embodiment, a program to be processed has a graph structure in which data and the process are divided. This graph is structured by considering a task and graph parallelism of the program.

[0014] When a compiler performs automatic vectorization and extraction of the graph structure on the program code shown in FIG. 1(A), a large number of threads as shown in FIG. 1(B) can be generated.

[0015] Hardware performs a dynamic register assignment and a thread scheduling on the large number of threads shown in FIG. 1(B), and thereby a parallel execution as shown in FIG. 1(C) can be performed. By performing the dynamic assignment of a register resource during execution, it may be possible to perform the parallel execution on multiple threads for different instruction streams.

[0016] Next, with reference to FIG. 2, a data process system 2 will be described. The data process system 2 is a system configuration example that includes a DFP (Data Flow Processor) 10 as an accelerator performing the dynamic register assignment and the thread scheduling.

[0017] The data process system 2 includes the DFP 10, an event handler 20, a host CPU 21, a ROM 22, a RAM 23, an external interface 24, and a system bus 25. The host CPU 21 is an arithmetic operation device that mainly processes data. The host CPU 21 supports an OS. The event handler 20 generates an interrupt process.

[0018] The ROM 22 is a memory only for reading. The RAM 23 is a memory for reading and writing. The external interface 24 is an interface for exchanging information with the outside of the data process system 2. The system bus 25 is for sending and receiving the information among the DFP 10, the host CPU 21, the ROM 22, the RAM 23, and the external interface 24.

[0019] The DFP 10 is positioned as an individual master placed for handling a heavy arithmetic operation load of the host CPU 21. The DFP 10 supports the interrupt generated by the event handler 20.

[0020] Next, with reference to FIG. 3, the DFP 10 will be described. As shown in FIG. 3, the DFP 10 includes a command unit 12, a thread scheduler 14, an execution core 16, and a memory subsystem 18.

[0021] The command unit 12 can communicate the information with a config interface. The command unit 12 also functions as a command buffer.

[0022] The thread scheduler 14 schedules the processing of the large number of threads as exemplified in FIG. 1(B). The thread scheduler 14 can perform the scheduling across the threads.

[0023] The execution core 16 has four processing elements of a PE#0, a PE#1, a PE#2, and a PE#3. The execution core 16 has a large number of pipelines that can be independently scheduled.

[0024] The memory subsystem 18 has an arbiter 181, a L1 cache 18a, and a L2 cache 18b. The memory subsystem 18 can communicate the information with a system bus interface and a ROM interface.

[0025] Next, with reference to FIGs. 4 and 5, the execution of the diagnostic code in the present embodiment will be described. An example shown in FIG. 4 is an example in which the diagnostic code is embedded, in advance, in the program having the graph structure. By executing the program in which the diagnostic code is embedded as described above, it may be possible to execute the diagnostic code at a timing intended in advance.

[0026] An example shown in FIG. 5 is an example in which the thread scheduler 14 includes a code reader 141 and an allocator 142 and thereby the diagnostic code is executed. A timer 20 outputs time point information to the thread scheduler 14. The thread scheduler 14 can read the diagnostic code and an expectation value that are stored in a code storage portion 18.

[0027] As a functional configuration element other than the normal thread scheduling function, the thread scheduler 14 includes the code reader 141 and the allocator 142.

[0028] The code reader 141 reads the diagnostic code stored in advance. The diagnostic code is stored in the code storage portion 18. Since the code storage portion 18 also stores the expectation value of a result obtained by executing the diagnostic code, the code reader 141 can also read the expectation value.

[0029] The allocator 142 causes the multiple process execution hardware to execute the diagnostic code so that the diagnosis is completed within a mean time to failure (MTTF). The allocator 142 allocates the execution of the diagnostic code so that the diagnosis is completed within the MTTF by using time point information output from the timer 20.

[0030] The diagnostic code allocation by the allocator 142 may be performed for each execution core, as shown in FIG. 3. The diagnostic code allocation by the allocator 142 may be performed for each arithmetic operation instrument of the execution core.

[0031] As shown in FIG. 6, the execution core 16 includes multiple arithmetic operation instruments. Specifically, the execution core 16 includes a thread arbiter 51, an arithmetic operation instrument A521, an arithmetic operation instrument A522, an arithmetic operation instrument B523, an arithmetic operation instrument B524, an arithmetic operation instrument C525, an arithmetic operation instrument C526, a result register A531, a result register A532, a result register B533, a result register B534, an expectation value register C535, an expectation value result D536, and a comparator 54.

[0032] The thread arbiter 51 allocates the process to the arithmetic operation instrument A521, the arithmetic operation instrument A522, the arithmetic operation instrument B523, the arithmetic operation instrument B524, the arithmetic operation instrument C525, and the arithmetic operation instrument C526. In accordance with the diagnostic code allocation by the allocator 142, the thread arbiter 51 allocates the diagnostic code execution to the arithmetic operation instrument A521, the arithmetic operation instrument A522, the arithmetic operation instrument B523, the arithmetic operation instrument B524, the arithmetic operation instrument C525, and the arithmetic operation instrument C526.

[0033] The arithmetic operation instrument A521, the arithmetic operation instrument A522, the arithmetic operation instrument B523, the arithmetic operation instrument B524, the arithmetic operation instrument C525, and the arithmetic operation instrument C526 execute the allocated processes. The arithmetic operation instrument A521 and the arithmetic operation instrument A522 have the same configuration and the same function. The arithmetic operation instrument B523 and the arithmetic operation instrument B524 have the same configuration and the same function. The arithmetic operation instrument C525 and the arithmetic operation instrument C526 have the same configuration and the same function.

[0034] The result register A531 stores the arithmetic operation result of the arithmetic operation instrument A521. The result register A532 stores the arithmetic operation result of the arithmetic operation instrument A522. The result register B533 stores the arithmetic operation result of the arithmetic operation instrument B523. The result register B534 stores the arithmetic operation result of the arithmetic operation instrument B524.

[0035] The expectation value register C535 stores the expectation value output from the arithmetic operation instrument C525. The arithmetic operation instrument C525 executes the expectation value process allocated by the thread arbiter 51, and stores the expectation value in the expectation value register C535. An expectation value register C536 stores the expectation value output from the arithmetic operation instrument C526. The arithmetic operation instrument C526 executes the expectation value process allocated by the thread arbiter 51, and stores the expectation value in the expectation value register C536.

[0036] The comparator 54 compares, for example, a value stored in the result register A531 with a value stored in the result register A532. In a case where the results are the execution results of the diagnostic code, when the values are matched, the comparator 54 determines that comparison result is normal. The comparator 54 compares, for example, the value stored in the result register A531 with a value stored in the expectation value register C536. In a case where the results are the execution results of the diagnostic code, when the values are matched, the comparator 54 may determine that comparison result is normal.

[0037] As shown in FIG. 7, the diagnostic code execution may be performed by the same type of arithmetic operation instrument at a different timing. As shown in FIG. 8, the diagnostic code execution may be performed by the same type of arithmetic operation instrument at the same timing.

[0038] According to the present embodiment described, the DFP 10 may correspond to an information processing apparatus of the present disclosure. The information processing apparatus includes a thread scheduler that allocates the process to multiple process execution hardware that process the program having the graph structure. The information processing apparatus includes the code reader 141 that reads the diagnostic code stored in advance and the allocator 142 that causes the multiple hardware to execute the diagnostic code so that the diagnosis is completed within the mean time to failure.

[0039] Since the allocator 142 causes the multiple process execution hardware to execute the diagnostic code so that the diagnosis is completed within the mean time to failure, it may be possible to perform the failure diagnosis using the process execution hardware already provided for the processing without duplicating the hardware for the failure diagnosis.

[0040] In the present embodiment, the coder reader 141 can also read the expectation value of the result obtained by executing the diagnostic code stored in advance.

[0041] In the present embodiment, the process execution hardware is the arithmetic operation instrument of the execution core.

[0042] In the present embodiment, the allocator 142 performs the allocation so that the diagnostic code is executed in each of the multiple process execution hardware at the different timings.

[0043] In the present embodiment, when the execution result of the diagnostic code shows the failure, the allocator 142 causes another process execution hardware having the same type to execute the diagnostic code again.

[0044] The embodiments have been described with reference to above specific examples. However, the present disclosure is not limited to these specific examples. Those skilled in the art appropriately modifies design to these specific examples, which are also included in the scope of the present disclosure as long as they have the features of the present disclosure. The elements, the arrangement, the conditions, the shape, etc. of the specific examples described above are not limited to those examples and can be appropriately modified. The combinations of elements included in each of the above described specific examples can be appropriately modified as long as no technical inconsistency occurs.

Claims

1. An information processing apparatus that includes a thread scheduler (14) configured to allocate a process to a plurality of process execution hardware configured to process a program having a graph structure, the information processing apparatus comprising: an execution core (16) including a thread arbiter (51), a plurality of arithmetic operation instruments, a plurality of result registers, and a comparator (54), the execution core (16) including the plurality of process execution hardware that are the plurality of arithmetic operation instruments; and a compiler configured to perform extraction of the graph structure to generate a plurality of threads; wherein the thread scheduler (14) comprises a code reader (141) configured to read a diagnostic code stored in advance; and an allocator (142) configured to cause the plurality of process execution hardware to execute the diagnostic code, wherein the allocator (142) is configured to allocate the execution of the diagnostic code so that the diagnosis is completed, the thread arbiter (51) is configured to allocate the process to the plurality of arithmetic operation instruments, and in accordance with the diagnostic code allocation by the allocator (142), allocate the diagnostic code execution to the plurality of arithmetic operation instruments, an arithmetic operation result of a corresponding one of arithmetic operation instruments is stored in a corresponding one of the result registers, the comparator (54) is configured to compare a value of a result of execution of the diagnostic code, which stored in one of the plurality of result registers, with a value of a result of execution of the diagnostic code, which is stored in another one of the plurality of result registers, and when the values match, to determine that the result of the comparison is normal.

2. The information processing apparatus according to claim 1, wherein: the code reader is configured to read an expectation value of a result obtained by executing the diagnostic code stored in advance.

3. The information processing apparatus according to claim 1 or 2, wherein: the allocator is configured to allocate the diagnostic code to the plurality of process execution hardware so that each of the plurality of process execution hardware executes the diagnostic code at a different timing from each other.

4. The information processing apparatus according to any one of claims 1 to 3, wherein: the allocator is configured to cause another process execution hardware having an identical type to execute the diagnostic code again when an execution result of the diagnostic code shows a failure.