JPH0544053B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a communication control device installed inside at least one or more nodes installed on a communication path of a computer system, etc. This aims to reduce the load on the central processing unit.

"Prior Art" FIG. 5 shows an example of a system in which a plurality of nodes are connected to the same communication channel.

In this diagram, communication path B includes node 1, node 2,
..., node i, ..., node M are installed.

Furthermore, the node i has a central processing unit CPU10,
Main memory 20, channel 30, communication control device 4
0 and an I/O interface 50. CPU 10 is connected to main memory 20, channel 30 and memory bus b1, and channel 30, communication control device 40 and I/O interface 50 are connected to I/O bus b2. Communication control device 40
controls communication operations with other nodes via communication path B.

In such a node i, a driver program executed by the CPU 10 compiles a plurality of communication requests from application programs set in the system into one and issues a command to the channel 30.

That is, as shown in FIG. 6A and B, (a) CPU1
The first communication request #1, second communication request #2, ..., #N generated in the application program No. 0 are stored as transmission messages in area A1 of the main memory 20, and DMA for each message sent within the program
WRITE request (data length, start address specification)
(c) is temporarily stored as a transmission message in the transmission buffer in the communication control device 40, and (d) is sequentially sent to the communication path B.

(e) When the received message is transmitted from the node that received the transmitted message through the communication path B, the communication control device 40 of the transmitting side node temporarily imports it into its internal reception buffer and interrupts the driver program. (f) The driver program also sends a DMA READ of the received message to channel 30.
Issues a request (data length, start address specification), and (g) stores this received message in the receive buffer within the driver program. Then, the driver program checks the destination of this received message (corresponding received message), and (h) copies it to the application program's reception buffer (area A2 on main memory 20).

Transmission messages and reception messages are exchanged using the operating procedure described above.

``Problems to be Solved by the Invention'' However, in the above procedure, the sending node sends outgoing messages in the order of the sending requests;
The arrival order of received messages returned from the other party's node is different from that of the sender of outgoing messages. That is, the timings at which multiple nodes on the other side return received messages do not match depending on their operating conditions.

Therefore, since the order in which received messages arrive is uncertain, the driver program first imports each received message into its own buffer and checks its destination (corresponding sent message) (g) to confirm the destination. This required a complicated procedure of copying the data to the application program, which placed a heavy load on the CPU.

The present invention is intended to solve such problems, and aims to reduce the load on central processing units within nodes that exchange transmitted and received messages as described above.

"Means for Solving the Problem" The present invention newly provides a buffer memory for transmission and reception within a communication control device, and its specific configuration is as follows.

That is, in a communication control device that is installed inside a node installed on a communication path and exchanges transmitted messages and received messages with at least one or more nodes, it stores all transmission requests to other nodes that occur to the node. , a buffer memory is provided to store all received information from other nodes in response to the transmission request, and when a transmission message is generated, the transmission/reception DMA is activated by the driver program, and when the reception message is received, the application program stores the buffer memory. The communication control device is characterized in that a received message is read out and a transmission/reception operation is completed.

[Operation] When a communication request occurs, the communication control device of the present invention stores the transmission request in a buffer memory at once by activating the DMA transmission/reception of the driver program, and the received message as a response is stored in the buffer memory. Once stored in the application
The program directly reads the contents of this buffer memory without the intervention of a driver program and completes the transmit/receive operation.

"Embodiment" FIG. 1 shows the configuration of a communication control device 40 in which the present invention is implemented.

In this figure, 41 is a communication interface directly connected to communication path B, 42 is a host interface connected to CPU 10, 43 is a control unit of this communication control device 40, and 44 stores a plurality of transmitted messages and received messages. It is a buffer memory that can be used. The communication interface 41 sends the transmitted message in the buffer memory 44 onto the communication path B, and also takes in the received message on the communication path B into the buffer memory 44.

The buffer memory 44 also includes a transmission channel section 441 that stores all transmission messages to other nodes generated by the CPU 10, and a reception channel section 442 that stores all reception messages sent back via communication path B. be done.

A flowchart of the operation of such communication control device 40 is shown in FIG.

First, when a communication command is given from the CPU 10, a variable I=0 is set.

The transmission message generated from the CPU 10 is transmitted to the transmission channel section 44 of the buffer memory 44.
1 and sequentially store them as I=I+1.

When the storage of the transmitted message is completed, the I value at this time is set to M, the variable I is set to 0 again, and the transmitted message stored in the transmission channel section 441 is stored as I.
= M to the destination node.

Next, there is a step of receiving received messages, and the received messages are sequentially stored in the buffer memory 44.
The information is stored in the reception channel section 442 of . At this time as well, set the variable I=0, set I=I+1, and set I=M
All received messages equal to the number of transmitted messages are stored in the reception channel section 442 until .

Here, each received message contains the identification information (destination) of the corresponding transmitted message by the echo function of each node, and by adding the reception channel section 442 read command to the application program, the driver program can be read. The received message can be directly transferred to the area A2 on the main memory 20 without any intervention. That is, conventionally, a driver program was activated every time a received message was returned and transferred the received message to the application program, but such processing operations can be omitted.

Next, specific transmission and reception of messages using the buffer memory 44 will be explained with reference to FIG.

Figure 3a shows the transmission buffer area A1 and reception buffer area in the application program.
A2 (area on the main memory 20), and the application program stores transmitted messages in the area A1 in the order of request generation (#1, #2, . . . , #N). Note that area A2 is an area where a received message returned from the destination node of the transmitted message is finally stored.

Now, (b) the message sent from the application program (area A1 of main memory 20) is
Depending on the driver program, (c) #1 transmission message DMA WR1TE (data length, start address)
The #N transmission message DMA WRITE (data length, start address) is set and sent to the channel 30 in sequence. On the other hand, at this point, the driver program is simultaneously sending channels #1 to #30.
Requests activation of DMA READ for #N received message (data length, start address). and,
By starting the driver program's DMA WRITE, the transmitted messages are sequentially transferred to the buffer memory 44.
The requests are stored in the transmission channel section 441 in the order in which the requests were generated.

Next, the control unit 43 in the communication control unit 40
The transmitted message in buffer memory 44 is sent to communication path B.

(d) When each transmitted message arrives at the destination node and each node sends out a received message, the node that sent the transmitted message receives the received message in sequence.

At this time, the received messages are stored in the reception channel section 442 in the order of arrival. However, the received message includes identification information of the corresponding sent message.

(e) The application program has already received the received message by the driver program.
Since DMA READ is activated, the received message in the receive channel section 442 is transferred to the main memory 2.
Immediately start transferring to area A2 of 0. When the transfer is completed, a transmission/reception completion interrupt is issued to the driver program, and the transmission/reception operation is completed.

Since the transmission and reception operations are performed as described above, the driver program, which has conventionally done this, temporarily stores the received messages that have arrived in a buffer within the driver program, checks the corresponding transmitted messages one by one, and uses the results to execute the application. It is possible to omit the operation of transmitting the received message to the Yon program.

Furthermore, instead of transmitting the received messages to the central processing unit CPU 10 after all received messages arrive at the request source as shown in the flowchart of FIG. 2, the reply order is #2, #1, #1, etc. as shown in FIG. At the time of #3,..., the #1 received message may be sent to the CPU 10 immediately when the #1 received message is returned, and then the #2 received message, #3 received message, etc. may be sent. .

"Effects of the Invention" As described above, the communication control device of the present invention provides the following effects.

Even if the order in which received messages arrive is undefined, the complicated procedure of the driver program checking the contents and copying them to the application program is omitted, reducing the load on the CPU.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a communication control device embodying the present invention, FIG. 2 is a flowchart showing the operation of the device of the present invention, FIG. 3 is a schematic diagram of the operation of the device of the present invention, and FIG. 4 is a diagram showing the operation of the device of the present invention. A schematic diagram of the operation when the operation of the device is partially changed. Figure 5 is an example of a system in which multiple nodes are connected to the same communication path. Figures 6A and B are diagrams of the conventional device when sending and receiving messages. It is an operation explanatory diagram. 10... central processing unit CPU, 20... main memory, 30... channel, 40... communication control device,
41...Communication interface, 42...Host interface, 43...Control unit, 44...
...Buffer memory, 441...Transmission channel section, 442...Reception channel section, 50...I/O
Interface, B...communication path, b1...memory bus, b2...I/O bus.

Claims (1)

[Claims] 1 installed inside the node installed on the communication path,
In a communication control device that exchanges transmitted messages and received messages with at least one or more nodes, all transmission requests to other nodes generated at the node are stored, and all received information from other nodes in response to the transmission requests is stored. A buffer memory for storing is provided, and when a transmit message is generated, a transmit/receive DMA is activated by a driver program, and when a receive message is received, the received message is read from the buffer memory by an application program to complete the transmit/receive operation. Characteristic communication control device.