JPH0335346A - Mutual diagnostic method for multicomputer system - Google Patents

Abstract

PURPOSE:To reduce the overhead by recording a fact that the normal message communication is performed into a control field of a shared memory and omitting the mutual diagnoses in accordance with the reference results of the diagnoses carried out in each mutual diagnostic cycle. CONSTITUTION:The control fields 13A - 13C are secured on a shared memory 12 of a system to record the communication confirming information showing a fact that the normal message communication is carried out between the computers 11A and 11B which share the memory 12. Each of both computers 11A and 11B contains a normal message communication means to record the communication confirming information to the fields 13A - 13C when the normal message communication is carried out. Furthermore a mutual diagnostic means is added to carry out the mutual diagnoses in accordance with the result of decision showing whether the normal message communication is carried out or not between both computers by reference to the fields 13A - 13C at the mutual diagnoses carried out in each fixed cycle. When the execution of the normal message communication is confirmed, the mutual diagnoses are omitted and the corresponding communication confirming information is erased out of the fields 13A - 13C. As a result, the overhead due to the mutual diagnoses can be reduced with no deterioration of the diagnostic performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a mutual diagnosis method suitable for reducing the load of mutual diagnosis processing in a multi-computer system.

(Prior Art) Generally, a multi-computer system includes a plurality of computers and a shared memory shared by these computers. Conventionally, mutual diagnosis in this type of multi-computer system is carried out by setting a fixed period of time, sending messages to other computers every period, and checking the response messages to the sent messages within a certain period of time. It was done. Message communication for the purpose of mutual diagnosis is called mutual diagnosis message communication.

In the mutual diagnosis described above, since mutual diagnosis messages must be exchanged at regular intervals, there is a problem in that the overhead caused by the mutual diagnosis becomes noticeable when the load on the computer is high or when the diagnosis cycle is short.

In order to reduce this overhead, there may be a method in which mutual diagnosis is performed irregularly using the idle time of the computer, or a method in which the diagnosis cycle is set longer. However, this method sacrifices diagnostic performance and may cause a delay in abnormality detection in a multi-computer system, making it difficult to apply.

(Problem to be Solved by the Invention) As mentioned above, in the mutual diagnosis method in the conventional multi-computer system, mutual diagnosis messages must be exchanged at regular intervals in order to reliably and promptly detect system abnormalities. Therefore, there was a problem that the system overhead was large.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a mutual diagnosis method for a multi-computer system that can reduce the overhead in mutual diagnosis of a multi-computer system without sacrificing diagnostic performance.

[Structure of the Invention] (Means for Solving the Problems) This invention provides normal message communication (different from mutual diagnostic message communication) on a shared memory of a multi-computer system between computers that share this shared memory. In addition to providing a control field in which communication confirmation information indicating that message communication (message communication) has been carried out, when normal message communication is carried out in each of the above computers, communication confirmation information indicating that is recorded in the control field. During mutual diagnosis at regular intervals, the normal message communication means to record and the control field are referred to to determine whether or not normal message communication has occurred with the other computer, and based on the result of this determination, mutual diagnosis is performed. (0 mutual diagnosis means is provided, and when it is determined that normal message communication has been carried out, mutual diagnosis is omitted and the corresponding communication confirmation information is deleted from the control field. That is.

(Function) According to the above configuration, when normal message communication is performed between computers as necessary, communication confirmation information indicating this is recorded in the control field on the shared memory. The fact that normal message communication has occurred means that the communication partner is normal. Therefore, recording the communication confirmation information in the control field as described above is equivalent to performing mutual diagnosis and recording that fact when the result is normal. Therefore, by referring to the control field when attempting to execute mutual diagnosis at regular intervals in a computer, it is possible to determine whether normal message communication was normally performed with the mutual diagnosis partner during the most recent mutual diagnosis cycle. It becomes possible to determine whether or not. Therefore, in the above configuration, when it is determined by referring to the control field that normal message communication has been performed normally with the mutual diagnosis partner, an alternative process for mutual diagnosis is performed and a normal determination is made. As a result, the mutual diagnosis in the corresponding period is omitted, and the corresponding communication confirmation information is deleted from the control field. On the other hand, if the corresponding communication confirmation information is not recorded and it cannot be determined that normal message communication between the mutual diagnosis partner was carried out normally, mutual diagnosis will be performed as before. .

(Embodiment) FIG. 1 is a block diagram showing an embodiment of a multi-computer system to which the present invention is applied. , In the same figure, IIA, IIB, IIc 4;! A computer 12 is a shared memory shared by the computers 11A-11c. Message communication between the computers 11A-110 is performed via the shared memory 12. In a predetermined area of this shared memory 12, computers 11A, 11B,
Three control fields 13A, 1 corresponding to IIc
3B.

13c is secured. Control field 13A is computer 1
From 1A to other computers (here, computer 11B, tic
), the control field 13B is a field for indicating that normal message communication has been confirmed for the computer 11B to the fine needle calculator (here, the computer 11c).

11A), and a control field 13c is a field for indicating that normal message communication has been confirmed for the computer 11C (computer 11A).
This field is used to indicate that normal message communication with IIB) has been confirmed.

FIG. 2 shows the format of control fields 13A-13c of FIG. As shown in the figure, control field 1
Bit 0 of 3A is a transmission confirmation bit indicating that computer 11A has sent a normal message to computer 11B, and bit 1 is a reception confirmation bit indicating that computer 11r3 has received a normal message from computer 11A. , bit 2 is a transmission confirmation bit indicating that the computer U^ has sent a normal message to the computer 11c, and bit 3 is a reception confirmation bit indicating that the computer 11G has received a normal message from the computer 11A. , are assigned respectively. Furthermore, bit O of the control field 13B is a transmission confirmation bit indicating that the computer 11B has sent a normal message to the computer 11C, and bit 1 is a transmission confirmation bit indicating that the computer IC has received a normal message from the computer 11B. Bit 2 for reception confirmation bit
is assigned to a transmission confirmation bit indicating that computer 11B has sent a normal message to computer 11A, and bit 3 is assigned to a reception confirmation bit indicating that computer 11A has received a normal message from computer 11B. ing. Furthermore, bit O of the control field 13c is a transmission confirmation bit indicating that the computer ttC has sent a normal message to the computer 11A, and bit 1 is a transmission confirmation bit indicating that the computer 11A has received a normal message from the computer +IC. In the reception confirmation bit, bit 2 is a transmission confirmation bit indicating that computer 11G has sent a normal message to computer 11B, and bit 3 is in computer 1.
Each bit is assigned to a reception confirmation bit indicating that 1B has received a normal message from the computer+IC.

FIG. 3 shows a flowchart for explaining the mutual diagnosis operation between the computer 11A and the computer 11B shown in FIG.

Next, the operation of one embodiment of the present invention will be described in FIGS. 1 to 3 above.
This will be explained with reference to the figures as appropriate.

First, in the multi-computer system shown in FIG.
This will be explained using IB normal message communication as an example. Calculator 11
A, IIB are normal functions (normal message communication)
, when a message is sent to the thin needle calculator, the control field 13A secured in the shared memory 12 is
, 13B turns on the corresponding transmission confirmation bit. As a result, for example, if a normal message is sent from the computer 11A to the computer 11B, bit 0 of the control field 13A is turned on (“1”) by the computer +1A.
). Also, from the computer 11B to the computer 11A
If a normal message is sent to the computer 11B, bit 2 of the control field 13B is turned on by the computer 11B. Further, when the computer 11^, IIB receives a normal message from the thin needle calculator, it turns on the corresponding reception confirmation bit in the control field specific to the sender. As a result, if the computer 118 receives a message from the computer 11A, the control field 13
Bit 1 of A is turned on by computer 11B. Further, if computer +1A receives a message from computer 11B, bit 3 of control field 13B is turned on by computer 11A.

As described above, in this embodiment, when normal message communication is performed between computers, the transmission confirmation bit and reception confirmation bit of the corresponding control field are turned on.

Specifically, as described above, from the computer 11A to the computer 11
If a normal message is sent to computer 11B and received normally by computer 11B, control field 1
All bits 0.1 of 3A are turned on. Further, if a normal message is sent from the computer 11B to the computer 11A and is normally received by the computer 11A, both bits 2 and 3 of the control field 13B are turned on. Note that if a normal message is sent from the computer 11A to the computer 11c and is normally received by the computer ttC, it is clear that bits 2.3 of the control field 13A are both turned on.

Next, mutual diagnosis in the multi-computer system shown in FIG. 1 will be explained using an example in which the computer 11A performs mutual diagnosis with the eleventh computer 1113.

First, the computer 11A selects bit 0 of the control field 13A.
．． 1 is in the on state (step St in FIG. 3). If control field 13A
When at least one of bits 0 and 1 of is in the off state, the computer 11A performs mutual diagnosis with the computer 11B using a well-known method (step S2 in FIG. 3). Next, the computer 11A turns off (clears "0") all bits 0.1 of the control field 13A (step S3 in FIG. 3) and enters normal processing.

Then, after a certain period (predetermined mutual diagnosis period) has passed (
Step S4 in FIG. 3), the computer 11A again executes step Sl in FIG.
, 1 are all in the on state.

If bits 0 and 1 of the control field 13^ are both in the ON state, the computer 11A determines that normal message communication from the computer 11^ to the computer 11B is normal during the mutual diagnosis cycle. Assuming that the mutual diagnosis process in the current mutual diagnosis cycle is confirmed to be broken (therefore, the mutual diagnosis process in the current mutual diagnosis cycle is unnecessary), the process skips the mutual diagnosis process in step S2 of FIG. 3 and proceeds to step S3 of FIG. 3. . And the calculator +1A is the control field 1
After turning off all bits 0 and 1 of 3A, normal processing begins.

As described above, if all bits 0.1 of the control field 13A are in the on state, step St in FIG.
It can be confirmed that the normal message communication from the computer 11A to the computer 11B was performed normally within the most recent t-th mutual diagnosis cycle only by the determination process of step S2 in FIG. 3 as described above. There is no problem even if the diagnostic processing is omitted, and by omitting this mutual diagnostic processing, the computer 11
A, IIB can secure enough time for normal processing, reducing system overhead.

Note that when the computer 11A performs mutual diagnosis with the computer IIIC, it can be determined whether or not the original mutual diagnosis process can be omitted by checking the states of bits 2 and 3 of the control field 13A. it is obvious. Similarly, when the computer 11B performs mutual diagnosis with the computer C, the computer 11B checks the status of bits 0 and 1 of the control field 13B.
When performing mutual diagnosis between
By checking the states of bits 2 and 3 of B, it can be determined whether or not the original mutual diagnosis process can be omitted.The above description has been about mutual diagnosis in a multi-computer system, but the present invention relates to a system that performs mutual diagnosis. If so, it can be applied to other systems as well.

[Effects of the Invention] As detailed above, according to the present invention, the fact that normal message communication has occurred between computers means that the communication partner is normal, and normal message communication is carried out between computers. When a mutual diagnosis is made, the fact is recorded in a control field provided on the shared memory, and the above control field is referred to during mutual diagnosis in each mutual diagnosis cycle, and mutual diagnosis is performed according to the reference result. Since this configuration is omitted, the overhead caused by mutual diagnosis can be reduced compared to the conventional method in which mutual diagnosis is performed unconditionally at regular intervals. Furthermore, mutual diagnosis is omitted when normal message communication is normally performed between the corresponding computers in the corresponding mutual diagnosis cycle, and there is no adverse effect (deterioration of diagnostic performance) due to the omission of mutual diagnosis.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a multi-computer system to which the present invention is applied, and FIG. 2 shows the control field IIA, 1111 shown in FIG. The ttC format diagram, FIG. 3, is a flowchart for explaining the mutual diagnosis operation between the computer 11A shown in FIG. 1 and the computer 11B. 11A 1B 1C... Computer, 12... Shared memory, 3A 3B 3c... Control field. Mausoleum representative

Claims (1)

[Claims] In a multi-computer system comprising a plurality of computers and a shared memory shared by the plurality of computers, a message is normally exchanged between the computers on the shared memory. normal message communication means for recording the communication confirmation information in the control field when the normal message communication is performed in each of the computers; Mutual diagnosis means refers to the control field to determine whether or not the above-mentioned normal message communication has been performed with the other computer during mutual diagnosis at regular intervals, and executes mutual diagnosis according to the result of this determination. and when it is determined during the mutual diagnosis that the normal message communication has occurred, the mutual diagnosis is omitted and the corresponding communication confirmation information is deleted from the control field. Mutual diagnosis method in multi-computer systems.