JPH08212179A - Data communication device for multiprocessor system - Google Patents

Abstract

PURPOSE: To provide a data communication device for multiprocessor system which can perform the automatic selection between the message communication and the DMA (direct memory access) communication. CONSTITUTION: At a transmission node 31, a transmitting device selection means 13 decides whether the transmission data are larger than a prescribed data size. Then the means 13 selects a DMA transmitting device 15 if the transmission data are larger than the prescribed size. If not, the means 13 selects a message transmitting device 14. The device 15 sends the transmission data to a network 30 as a transmission signal of the DMA communication, and the device 14 sends the transmission data to the network 30 as a transmission signal of the message communication. At a reception node 32, a message receiving device 24 and a DMA receiving device 25 receive the reception signals from the network 30. Then a reception data integration means 23 integrates these received signals into the reception data.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a data communication device for a multiprocessor system, and more particularly to a data communication device for a multiprocessor system having a plurality of selectable communication means.

[0002]

2. Description of the Related Art This type of data communication device for a multiprocessor system is used by programs on different processors for exchanging data and synchronizing with each other.

Message communication is widely used as a data communication method for multiprocessor systems. Generally, in message communication, a buffer (transmission buffer) for writing transmitted data and a buffer (reception buffer) for temporarily storing received data are required. The data to be transmitted is once copied to the transmission buffer, and is sent out on the network by the transmitting device together with the header containing the destination address. The data transmitted through the network is fetched from the network by the receiving device and copied to the receiving buffer. Reception is completed by the recipient copying the data from the receive buffer. As described above, the message communication is not suitable for the communication of a large amount of data, which requires a large copy overhead because the data must be copied on both the transmitting side and the receiving side.

As another data communication method for a multiprocessor system, DMA (Dir) via a network is used.
There is communication by ect Memory Access (hereinafter referred to as DMA communication). In DMA communication, data is directly written in the memory area of the receiver. There is no difference from message communication in that data is sent via a network, but it has the advantage that no buffer is required on the way and copy overhead does not occur. However, since the sender needs to know the memory area for storing the received data in advance, a protocol for reserving the memory area of the receiver is required before performing the DMA communication. Also, depending on the hardware that performs the DMA, the receiver may not be able to know the end of the DMA only by the DMA communication. In that case, a protocol for notifying the end of the DMA is required. Generally, these protocols are realized by message communication. As described above, the DMA communication has a larger protocol overhead than the message communication, and is not suitable for communication of a small amount of data.

Conventionally, these data communication methods for multiprocessor systems have been provided as individual communication means.

[0006]

Conventionally, message communication and DMA communication have been provided as separate data communication means for multiprocessor systems. Therefore, any one of the programs for performing communication using these means may be used. It was necessary to explicitly select the communication method. Furthermore, in order to increase the efficiency of data communication across processors, it is necessary to appropriately combine message communication and DMA communication according to the size and type of data to be communicated.

Therefore, an object of the present invention is to provide a data communication device for a multiprocessor system in which selection between message communication and DMA communication is automated.

Another object of the present invention is to provide a data communication device for a multiprocessor system that improves the performance of data communication across processors by appropriately combining message communication and DMA communication according to the size and type of data. To provide.

[0009]

According to the present invention, in a transmission node for transmitting transmission data, a message transmitting device for transmitting the transmission data as a transmission signal by message communication, and the transmission data by DMA. A DMA transmission device for transmitting as a transmission signal by communication and whether or not the size of the transmission data is larger than a predetermined size is determined, and when the size of the transmission data is larger than the predetermined size, the DMA transmission device is selected. Otherwise, there is obtained a transmitting node comprising a transmitting device selecting means for selecting the message transmitting device.

Further, according to the present invention, in a receiving node for receiving a communication signal, a message receiving device for receiving the communication signal as a reception signal by message communication, and the communication signal as a reception signal by DMA communication. There is provided a receiving node comprising a DMA receiving device for receiving, and an integrating means for integrating a signal received by the message receiving device and a signal received by the DMA receiving device to generate received data.

Further, according to the present invention, a network connecting a plurality of computers, and a message communication device capable of transmitting any one type of data as a message from a sender to a recipient through the network, Through the network, the sender directly writes one kind of data to the memory address of the receiver, notifies the receiver of the end of writing and the data size, and the receiver reads the data from the memory address. , A data communication device capable of transmitting data, and a data communication device for performing data communication between programs across processors using the message communication device and the communication device using DMA, They are connected by the network, and each is a small means of communication across processors. And a plurality of computers each having the message communication device and the communication device using the DMA, each of which has the data communication device, and a program executed on the computer. A first program for transmitting and a second program for receiving data using the data communication device
In a multiprocessor system including the program, the data communication device includes a data receiving device and a data transmitting device, and the data transmitting device includes the first
According to the size of the data passed from the program, it is possible to automatically select one of the message communication device and the communication device using DMA, and transmit the data.
The data receiving device includes the message communication device and the DM.
A data communication device for a multiprocessor system is obtained which is capable of automatically selecting one of the communication devices using A and receiving the data and passing the data to the second program.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multiprocessor system incorporating a data communication device according to an embodiment of the present invention will be described with reference to FIG. In the multiprocessor system of FIG. 1, the transmission node 31 and the reception node 32 are connected via a network 30. Sending node 31
Includes a message transmitting device 14, a DMA transmitting device 15, and a data transmitting device 16. Message transmission device 1
4 and the DMA transmitter 15 are connected to the network 30. The data transmission device 16 includes a transmission data acceptance unit 11 and a transmission device selection unit 13. The transmission device selection means 13 is connected to the transmission data acceptance means 11, the message transmission device 14, and the DMA transmission device 15.

On the other hand, the receiving node 32 includes a message receiving device 24, a DMA receiving device 25 and a data receiving device 17. The message receiving device 24 and the DMA receiving device 25 are connected to the network 30. The data receiving / transmitting device 17 includes a received data extracting means 21 and a received data integrating means 23. Received data integration means 2
Reference numeral 3 is connected to the reception data extracting means 21, the message receiving device 24, and the DMA receiving device 25.

When data is transmitted from the sender 10 to the receiver 20, the data transmitter 16 receives the data from the sender 10 and based on the size thereof, the message transmitter 1
4 or the DMA transmitter 15 is selected to transmit the data. This data is transmitted as a message or DMA data via the network 30 to the transmitting node 31.
To the receiving node 32. Data receiving device 1
7 selects either the message receiving device 24 or the DMA receiving device 25, receives the message and the DMA data, extracts the data from them, and passes the data to the receiver 20.

Here, it is assumed that the message transmitting device 14 and the message receiving device 24 can handle a variable length message of any size, and the DMA communication is completed by receiving the message notifying the end of writing.

The processing performed inside the data transmission device 16 will be described with reference to FIG. 1 and FIG. 2 showing a flow chart of the processing of the transmission device selection means 13. The data transmission device 16 receives the data passed from the sender and its size by the transmission data receiving means 11. The transmission data receiving means passes the data and size to the transmission device selecting means 13 as they are.

The transmitter selection means 13 determines whether to use message communication or DMA communication based on the size of data. Specifically, it is determined whether or not the size of the data is a predetermined size, for example, a minimum DMA or more (step A1).
1). Here, the minimum DMA size indicates the minimum data size in which the DMA communication is more efficient than the message communication. This minimum DMA size is determined by the performance of message communication and DMA communication, and the value differs depending on the target multiprocessor system.

When the size of the data is smaller than the minimum DMA, the data is transmitted by message communication. In this case, the data body is first copied to the message, and the size of the data is added to the message (step A1).
4) Then, the message is transmitted using the message transmitting device 14 (step A15).

On the other hand, when the data size is equal to or larger than the minimum DMA, the data is transmitted by DMA communication. In this case, the data body is DMA-transferred to the designated address (step A12), and the transfer destination address and the data size are transmitted as a message to notify the completion of the DMA transfer (steps A13, A15).

Next, the processing performed inside the data receiving device 17 will be described with reference to FIG. 1 and FIG. 3 showing a flow chart of the processing of the received data integrating means 23. When receiving the message from the message receiving device 24 (step B11), the reception data integrating means 23 determines whether or not the message is a message notifying the completion of the DMA transfer, that is, a DMA notification message (step B12). . If the message is a DMA notification message, the data size is extracted from the message (step B14), and the body of the data is extracted from the transfer destination address (step B1).
5). If the received message includes the data body, the message is not a DMA notification message, and the data size and the data body are extracted from the message (step B13). The data body and size thus retrieved are passed to the receiver 10 by the reception data retrieval means 21.

In this embodiment, message communication and DMA communication are automatically used properly according to the size of data, thereby enabling efficient data communication.

Next, referring to FIG. 4, a multiprocessor system incorporating a data communication device according to an embodiment of the present invention will be described. In the embodiment shown in FIG. 1, only communication of one type of data is considered in one communication. Therefore, in the embodiment of FIG. 4, by adding the transmission data analysis means 12 and the reception data analysis means 22,
Plural pieces of data are combined so that they can be communicated as one piece of data, and plural pieces of data can be communicated by one communication.

The processing performed inside the data transmission device 16 will be described with reference to FIG. 4 and FIG. 5 showing a flow chart of the processing of the transmission device selection means 13. The data transmission device 16 receives one or more data and its type and size information from the sender 10 by the transmission data receiving means 11.

There are various methods for passing the data type and size information to the transmission data receiving means 11, but in this embodiment, the information is passed using the format string. FIG. 7 shows a list of descriptors used to describe this format string. With this descriptor,
“One 32-bit integer and four 8-bit integers, 10
The set of 20,000 pieces of double precision floating point number data is
It can be represented by a format string "% i% c [8]% d [100000]". The transmission data receiving means 11 passes the received data and format string to the transmission data analyzing means 12 as they are.

The transmission data analysis means 12 analyzes the format string and specifies the type and size of the data. That is,
Format string "% i% c [8]% d [10000
0] ”is given, it is said that the data is composed of three," 1 32-bit integer "," 4 8-bit integers ", and" 100,000 double-precision floating-point numbers ". Output analysis results. The analysis result and the data are passed to the transmission device selection means 13.

The transmission device selection means 13 extracts the type and size of one data from the passed analysis result and copies it to the message (step C11). Next, based on the size of the data, it is determined whether to use message communication or DMA communication, and the same processing as in the previous embodiment is performed. (Steps A11, A12, A13, A14). The above processing is repeated for the passed data, and when all is done, a message is transmitted (steps C12, A15). An example of the message transmitted at this time is shown in FIG. The message of FIG. 8 has the format string “% i% c [4]% d [1
000000] ", in this case,"% i%
The data body is written in the message in the portion c [4] ", and the transfer destination address of the data is written in the message in the portion"% d [100000] ".

Next, the processing performed inside the data receiving device 17 will be described with reference to FIG. 4 and FIG. 6 showing the flow chart of the processing of the received data integrating means 23. When receiving the message from the message receiving device 24 (step B11), the reception data integrating means 23 takes out the type and size of one data from the message (step D11), and the data body is DMA-transferred based on it. It is determined whether or not it is included in the message, and the same processing as that of the previous embodiment is performed accordingly (steps D12, B13, B1).
4, B15). When the above processing is completed for all the data in the message, the received data body and size are obtained by the reception data extracting means 21 by the recipient 20.
Passed to.

In this embodiment, the number of times of communication can be reduced by collecting a plurality of data, and the efficiency of communication can be improved by combining the message communication device and the DMA communication device.

Further, the DMA communication device 1 of the embodiments of the previous two examples
In the case where 5 has only the data transfer capability in page units or word units, it is necessary to change the transmitter selection means 13 and the reception data integration means 23 as follows.

The transmitting device selecting means 13 divides the data into a portion which fits within a page or word and a portion which does not fit within the page or word, and the data of the portion which does not fit is transmitted using the message transmitting device 14, and only the data of the fitting portion is sent. D
It is made possible to transmit using the MA transmitter 15.

The reception data integrating means 23 receives the data of the portion which does not fit from the message receiving device 24,
The data of the set portion is received from the DMA receiving device 25, and the data can be combined and restored to one original data.

With such a modification, even if the DMA communication device has a limited transfer capability, the data communication device of the present invention can be incorporated and the efficiency of data communication across processors can be improved.

Next, the case where the data communication device for a multiprocessor system of the present invention is incorporated in a part of the operating system will be described. Here, N is the inter-processor communication mechanism of the Mach operating system.
An application example to the ORMA IPC will be shown. NORMA IP
C is an extension of Mach's inter-process communication mechanism to inter-processor communication, and can perform inter-process communication without being aware of whether the process of the communication partner is on the same processor or on another processor. it can.

The message (Mach message) handled by the Mach inter-process communication mechanism is a "typed message". The structure of the Mach message is shown in FIG. Mach message has one message header 60
And a set of one or more message types 61 and message bodies 62. That is, a plurality of data can be included in one message. The message header 60 includes an ID for designating a destination process, an ID indicating a source process, the size of the entire message, and the like. The message type 61 includes information about the data body such as a type, size, and a flag indicating whether it is OOL (out-of-line) data. Here, the OOL data is to include only a pointer to the data in the message, not the body of the data. If it is not OOL data, the message body contains the data body, but if it is OOL data, it only contains a pointer to the data.

When a Mach message having such a structure is exchanged between processors, the simplest method is to use message communication for the Mach message and DMA communication for the OOL data portion. But,
In this method, message communication may be used for a very large Mach message, or DMA communication may be used for a small arrangement, and thus efficient communication is not always possible. Therefore, the data transmission device 16 and the data reception device 17 are incorporated into the NORMA IPC so that appropriate communication means can be selected and combined according to the type and size of data.

A block diagram of this embodiment is shown in FIG. The sender 10 calls the Mach system call to pass the data to the Mach message transmission processing unit 81. The data passed here is already a Mach message in the format as shown in FIG. The Mach message transmission processing unit 81, if the delivered Mach message is addressed to another processor, delivers it to the data transmission device 16. In the processing inside the data transmission device 16, the Mach message is directly transmitted by the transmission data analysis means 1.
2 is the same as in the previous example, except that it is passed to the Mach message instead of the format string. Similarly to the previous embodiment, the data receiving device 17 also takes out the data, converts it into the form of a Mach message, and passes it to the Mach message reception processing unit 82.

As described above, by incorporating the multiprocessor data communication device of the present invention as a part of the function of the operating system, even when the data communication is performed using the data communication means prepared by the operating system, the communication can be performed. You can increase efficiency.

[0038]

As described above, the data communication device for a multiprocessor system according to the present invention provides the selection of message communication and DMA communication as a part of the function of the data communication device, and is automated, so that When writing a program for data communication, it is not necessary to consider whether to use message communication or DMA communication, which simplifies programming.

Further, since the message communication and the DMA communication are properly combined according to the size and type of the data, the performance of the data communication is improved.

Further, even when the DMA communication device has a limited transfer capability such as a page unit or a word unit, the data device according to the present invention can be incorporated, so that it is not necessary to be aware of the limitation and programming is easy. Become.

[Brief description of drawings]

FIG. 1 is a block diagram showing a relationship between a configuration of a data communication device according to an exemplary embodiment of the present invention and other components.

FIG. 2 is a flow chart of processing of a transmitting device selecting means of FIG.

FIG. 3 is a flow chart of processing of a reception data integration unit of FIG.

FIG. 4 is a block diagram showing a configuration of another embodiment in which a transmission data analysis means and a reception data analysis means are added to the embodiment of FIG.

5 is a flow chart of processing of a transmission device selection means of FIG.

FIG. 6 is a flowchart of the processing of the reception data integrating means in FIG.

7 is an example of a format descriptor passed to the transmission data analysis means of FIG.

FIG. 8 is an example of a message generated by the transmission device selection means of FIG.

FIG. 9 is a block diagram showing the configuration of another embodiment in which the transmitting device selecting means and the received data integrating means of the present invention are added to a part of the communication device of the operating system.

FIG. 10 is an example of a Mach message.

[Explanation of symbols]

 10 program to be a sender of data 11 transmission data acceptance means 12 transmission data analysis means 13 transmission device selection means 14 message transmission device 15 DMA transmission device 16 data transmission device 17 data reception device 20 program to be a data receiver 21 received data Extraction means 22 Reception data analysis means 23 Reception data integration means 24 Message reception device 25 DMA reception device 30 Network 31 Transmission node 32 Reception node 81 Mach message transmission processing unit 82 Mach message reception processing unit 83 Mach kernel

Claims (7)

[Claims] 1. A transmission node for transmitting transmission data, a message transmitting device for transmitting the transmission data as a transmission signal by message communication, and a DMA for transmitting the transmission data as a transmission signal by DMA communication. The transmitter determines whether or not the size of the transmission data is larger than a predetermined size, and the DMA if the size of the transmission data is larger than the predetermined size.
And a transmitting device selecting means for selecting a transmitting device or selecting the message transmitting device otherwise. 2. The device according to claim 1, further comprising means for determining whether or not the transmission data is the last data, and executing the selection by the transmission device selection means when the transmission data is the last data. Sender node. 3. A receiving node for receiving a communication signal, a message receiving device for receiving the communication signal as a reception signal by message communication, and a DMA for receiving the communication signal as a reception signal by DMA communication. A receiving node comprising: a receiving device; and integrating means for integrating a signal received by the message receiving device and a signal received by the DMA receiving device to generate received data. 4. The transmission node according to claim 1 or 2 and the reception node according to claim 3 are connected via a network, and a transmission signal transmitted from the transmission node is communicated by the reception node through the network. A data communication system characterized in that the data communication system is configured to be received as. 5. A network connecting a plurality of computers, a message communication device capable of transmitting any one type of data as a message from a sender to a recipient via the network, and via the network. , The sender directly writes one kind of data to the memory address of the receiver, notifies the receiver of the end of writing and the data size, and the receiver reads the data from the memory address to transmit the data. A communication device using DMA, a data communication device for performing data communication between programs across processors using the message communication device and the communication device using DMA, and being coupled by the network. ,
A plurality of computers each having at least the message communication device and a communication device using the DMA as means of communication across processors, and a plurality of computers each having the data communication device; and a program executed on the computer. A multiprocessor system including a first program for transmitting data using the data communication device and a second program for receiving data using the data communication device, wherein the data communication device is a data receiving device And a data transmission device, and the data transmission device automatically selects either the message communication device or the communication device using DMA according to the size of the data passed from the first program. , Data can be transmitted, and the data receiving device Equipment and DM
A data communication device for a multiprocessor system, which is capable of automatically selecting any of the communication devices using A and receiving the data, and passing the data to the second program. 6. The data communication device for a multiprocessor system according to claim 5, wherein the data transmission device receives a plurality of data together with its type and size, and combines the information into one structured data. In addition to having a function, it also has a function of automatically combining and transmitting the message communication device and a communication device using DMA to individual data based on information of the type and size of the data. Is a data communication device for a multiprocessor system having a function of receiving the structured data and decomposing it into a plurality of original data and its type and size. 7. The data communication device for a multiprocessor system according to claim 5, wherein when the communication device using the DMA has only a transfer capability in page units or word units, the data transmitting device is Divide one data into a first part that does not fit in a page or word and a second part that does not fit, the second part transmits using the message communication device, and only the first part is the DMA. The data receiving device has a function of transmitting using the communication device used, the data receiving device receives the data of the first part using the message communication device, and uses the DMA of the data of the second part. Received using the communication device that
A data communication device for a multiprocessor system, which has a function of combining those data and returning to one original data.