Data communication system which guarantees at a transmission station the arrival of transmitted data to a receiving station and method thereof

• US 5,592,628 A
• Filed: 02/01/1996
• Issued: 01/07/1997
• Est. Priority Date: 11/27/1992
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ishizaka, Ken-ichi, Ueno, Haruhiko, Ikeda, Masayuki, Shinjo, Naoki, Utsumi, Teruo, Nagasawa, Shigeru, Kobayakawa, Kazushige, Dewa, Masami
• Primary Examiner(s): KIM, KENNETH S
• Application Number:
  US08/595,505
• Time in Patent Office: 341 Days
• Field of Search: 395/183.19, 395/200.13, 395/852, 395/873, 395/700
• US Class Current: 709/200
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 15/17375 One dimensional, e.g. linear array, ring
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes

Abstract

Any two of multiple processor elements are coupled with each other via a data communication network that has a definite communication buffer length and includes multiple communication buffers. A packet having a header and body is created using processed data, and then transferred by a transmitting unit. After sending the processed data, the transmitting unit transmits dummy data, having a body which is longer than the communication buffer length in the data communication network, to the same receiving station as the one to which the processed data is transmitted. The transmitting unit then guarantees a processor element serving as a receiving station the arrival of preceding processed data and the header. Control data representing cache invalidation waiting is embedded in the header of the dummy data. When a transmitting end terminates transfer of the dummy data, the sending station can guarantee the termination of cache invalidation, which is performed by the processor element serving as a receiving station to attain the consistency of the contents of preceding storage data main storage and a cache memory.

Claims

1. A data communication system having a transmission station which serially transmits processed data in a first given order to a receiving station, said data communication system guaranteeing, to the transmission station, an arrival of the processed data at the receiving station, said data communication system comprising:

data communication network means for connecting a communication path between the transmission and receiving stations through at least one communication buffer; and

communication guarantee means, provided in said transmission station, for serially transmitting dummy data, having a length at least as long as a data length of all of said communication buffers existing in the established communication path formed by said data communication network means, in a second given order through all of said communication buffers existing in the established communication path to the receiving station subsequently to the processed data that is serially transmitted from the transmission station through all of said communication buffers existing in the established communication path, wherein the processed data, which has been transmitted prior to the dummy data, is forced in a run from said data communication network means at a time point when the transmission of the dummy data to said data communication network means is completed, thereby guaranteeing, to the transmission station, the arrival of the processed data at the receiving station.

2. A data communication system according to claim 1, wherein the dummy data transmitted by said communication guarantee means is a packet comprising a header and a body, wherein the length of the packet is at least as long as the data length of all of said communication buffers existing in the established communication path and the packet is serially transmitted through all of said communication buffers existing in the established communication path.

3. A data communication system according to claim 1, wherein the dummy data transmitted by said communication guarantee means is a packet comprising a header and body, and a data length of said body is at least as long as the data length of all of said communication buffers existing in the established communication path, wherein the processed data and the dummy data header are serially forced in a run from said data communication network means by the dummy data through all of said communication buffers existing in the established communication path at a time point when the transmission of the dummy data into said data communication network means is completed, thereby guaranteeing, to the transmission station, the arrival of the dummy data at the receiving station.

4. A data communication system according to claim 3, wherein said communication guarantee means transmits said dummy data with control data, wherein the control data designates operations to be performed on the processed data by a processing unit serving as the receiving station and is embedded in the dummy data header.

5. A data communication system according to claim 4, wherein said communication guarantee means sets the data length (DL₀) in said body of the dummy data to a data length provided as a sum of the data length (DL₁) of all of said communication buffers existing in the established communication path and a transfer data length (DL₂) corresponding to a time required until the dummy data header is interpreted by the receiving station and an execution of the operations designated by the control data is completed, and said communication guarantee means guarantees, to the transmission station, the arrival of the processed data and the dummy data header at the receiving station and an end of the execution of the operations designated by the dummy data header.

6. A data communication system according to claim 1, wherein the transmission station includes a transmission end reporting means for detecting the termination of the transmission of the dummy data to the receiving station and reports the termination to other processing units.

7. A data communication method in which a plurality of processing units, each of which has main storage means and an instruction processing unit and which executes processes in parallel, communicates with one another via data communication network means, said data communication network means connecting a communication path which uses at least one communication buffer and has a definite communication buffer length, said data communication method comprising:

a processed data transmitting step of serially transmitting processed data in a first given order from transmission means provided for a first one of said plurality of processing units through said data communication network means to a second one of said plurality of processing units designated as a receiving station; and

a communication guaranteeing step, provided for said transmission means, of serially transmitting dummy data, having a data length at least as long as said definite communication buffer length, in a second given order from the transmission means through all of said communication buffers in the communication path subsequently to the transmission of the processed data from said transmission means, said communication guaranteeing step forcing in a run the processed data from said data communication network means by the dummy data at a time point when the transmission of the dummy data to said data communication network means is completed, thereby guaranteeing, for the transmission means, the arrival of the processed data at the receiving station.

8. A data communication method according to claim 7, wherein the dummy data to be transmitted at said communication guaranteeing step is a packet comprising a header and a body.

9. A data communication method according to claim 7, wherein the dummy data to be transmitted at said communication guaranteeing step is a packet comprising a header and a body, and is serially transmitted with a data length of said body at least as long as said definite communication buffer length, and the processed data and the dummy data header are forced in a run from said data communication network means by said dummy data at a time point when the transmission of the dummy data to said data communication network means is completed, thereby guaranteeing, to the transmission means, the arrival of the processed data and the dummy data header at the receiving station.

10. A data communication method according to claim 9, wherein at said communication guaranteeing step, the dummy data is transmitted with control data, wherein the control data designates operations to be performed on the processed data by said second one of said plurality of processing units serving as the receiving station, and the control data is embedded in the dummy data header.

11. A data communication method according to claim 10, wherein at said communication guaranteeing step, the data length (DL₀) of said body of the dummy data is set to a data length provided as a sum of said definite communication buffer length (DL₁) and a transfer data length (DL₂) corresponding to the time necessary until the control data of the dummy data header is interpreted and execution of the designated operations is completed, wherein the arrival of each of the processed data and the dummy data header at the processing unit designated as the receiving station and an end of the execution of the operations designated by the dummy data header is guaranteed to the transmission means.

12. A data communication method according to claim 7, wherein each of said processing units comprises:

a cache memory, provided for said instruction processing unit, for storing the same data as the processed data written to a predetermined address by an access of said main storage means;

storage consistency control means, that when the processed data is written in said main storage means, compares the access address with the registered address in said cache memory, wherein when the access address and the registered address coincide, said storage consistency control means transmits the same data in said cache memory to a queue as an invalidation address for invalidating the same data in said cache memory, sequentially takes out the same data from said queue, executes the cache invalidation and maintains the consistency between contents of said main storage means and said cache memory;

cache invalidation waiting means, that while said storage consistency control means is executing the cache invalidation, stops the data reception for a write access to said main storage means; and

control data receiving means, that when interpreting the header of the received data as a cache invalidation wait instruction, operates said cache invalidation means to stop the data reception and allows said storage consistency control means to execute the cache invalidation;

wherein at said communication guaranteeing step, the dummy data is transmitted with control data, wherein the control data represents cache invalidation waiting to said processing unit designated as the receiving station, and is embedded in the dummy data header, and the data length (DL₀) of said body of the dummy data is provided as a sum of said definite communication buffer length DL₁ in said data communication network means and the transfer data length (DL₂) corresponding to processing time required until said processing unit designated as the receiving station interprets the control data in the dummy data header and stops the data reception for cache invalidation waiting;

wherein the arrival of each of the processed data and the header of the dummy data at said processing unit designated as the receiving station, the writing access into said main storage means of the processed data, and the termination of the cache invalidation is guaranteed to the transmission means.

13. A data communication method according to claim 7, further comprising a transmission end reporting step of detecting the termination of the transmission of the dummy data executed at said communication guaranteeing step and, in response, issuing a transmission end report to a barrier network means;

and

passing control by said barrier network means to the parallel processing when said barrier network means receives transmission end reports from all of said processing units that have executed parallel processing.

14. A data communication method according to claim 7, wherein said main storage means of said unit has a dummy data storage area, which stores meaningless data having a specified data length for use as the data length in the body of the dummy data, and at said communication guaranteeing step, data transfer is performed by designating said dummy data storage area as a write address.

15. A data communication method according to claim 7, wherein portions of said main storage means installed in said plurality of processing units are assigned as a global memory;

and all of said processing units access the global memory comprising said main storage means to execute the parallel processing.

16. A data communication system for guaranteeing, to a transmitting side, an arrival of processed data to a receiving side, said data communication system comprising:

a plurality of processing units, each of which has main storage means and instruction processing means and executes parallel processing;

data communication network means that couples any two of said plurality of processing units via at least one communication buffer, thereby establishing a communication path;

a plurality of transmission means installed in respective ones of said plurality of processing units, each one of said plurality of transmission means for serially transmitting the processed data in a first given order to any other one of said plurality of processing units serving as a receiving station;

a plurality of receiving means installed in respective ones of said plurality of processing units, each of said plurality of receiving means for receiving the processed data from any other one of said plurality of processing units;

a plurality of communication guarantee means, each of which serially transmits dummy data, having a data length at least as long as a data length of all of said communication buffers existing in the established communication path formed by said data communication network means, in a second given order to the receiving station subsequently to the processed data, wherein each of said plurality of communication guaranteeing means transmits the dummy data to force in a run the processed data from said data communication network means by the dummy data, thereby guaranteeing, to the transmission means, the arrival of the processed data at the receiving station at a time point when the transmission of the dummy data into said data communication network means is completed.

17. A data communication system according to claim 16, wherein the dummy data to be transmitted by said each communication guarantee means is a packet comprising a header and a body.

18. A data communication system according to claim 16, wherein the dummy data to be transmitted by each of said communication guarantee means is a packet comprising a header and a body, said packet having a data length at least as long as the data length of all of said communication buffers existing in the established communication path in said data communication network means, wherein the processed data and the dummy data header are forced in a run from said data communication network means by the dummy data at a time point when the transmission of the dummy data into said data communication network means is completed, thereby guaranteeing, to the transmission means, the arrival of the processed data at said receiving means.

19. A data communication system according to claim 18, wherein said each communication guarantee means adds control data to the dummy data header to designate an operation which is executed by said processing unit serving as the receiving station with respect to the processed data, and transmits the resultant dummy data.

20. A data communication system according to claim 18, wherein said communication guarantee means sets the data length (DL₀) of the body of the dummy data to a data length provided as a sum of the communication buffer length (DL₁) of all of said communication buffers existing in the established communication path and a transfer data length (DL₂) corresponding to a time required until the receiving station decodes the dummy data header and the execution of the operation designated by the control data is completed, and the arrival of each of the processed data and the dummy data header at the receiving station, and a stopping operation of data reception designated in the control data of the dummy data header is guaranteed.

21. A data communication system according to claim 16, wherein each of said plurality of processing units comprises:

a cache memory provided for said instruction processing means and stores same data as the processed data written in the predetermined address by an access to said main storage means;

storage consistency control means, that when the processed data is written in said main storage means, compares the processed data with a registered address of said cache memory, wherein when the processed data agrees with the registered address, holds the address in a queue as an invalidation address for use in invalidating the same data in said cache memory, and extracts such addresses sequentially from said queue and then executes cache invalidation to maintain consistency between contents of said main storage means and said cache memory;

cache invalidation waiting means, that while said storage consistency control means is executing cache invalidation, stops the data reception for a writing access to said main storage means; and

control data receiving means, that when interpreting the dummy data header as control data representing cache invalidation waiting, operates said cache invalidation;

wherein said communication guarantee means embeds the control data, which represents the cache invalidation waiting to the processing unit serving as the receiving station, in the dummy data header, and sets the data length (DL₀) in said body of the dummy data to a data length provided as a sum of the communication buffer length (DL₁) of all of said communication buffers existing in the established communication path in said data communication network means and a transfer data length (DL₂) corresponding to a processing time required until said processing unit serving as the receiving station interprets the control data in the dummy data header and stops the data reception for the cache invalidation waiting; and

the arrival of each of the processed data and the dummy data header at said processing unit serving as the receiving station, and the termination of the writing access to said main storage means and the cache invalidation with respect to the processed data designated by the dummy data header are guaranteed.

22. A data communication system according to claim 16, further comprising barrier network means;

wherein said each processing unit includes a transmission end reporting means for detecting the termination of the transmission of the dummy data and issues a transmission end report to said barrier network means, and said barrier network means passes control to the parallel processing in response to receiving transmission end reports from all of said processing units which have executed parallel processing.

23. A data communication system according to claim 16, wherein said main storage means of said processing unit has a dummy data storage area, which stores meaningless data having a specified data length for use as the data length in the body of the dummy data, in said main storage means thereof;

and said dummy data storage area is designated in a write address and the dummy data is transferred thereto.

24. A data communication system according to claim 16, wherein portions of each of said main storage means installed in respective ones of said plurality of processing units are assigned as a global memory;

and all of said processing units access the global memory to carry out the parallel processing.

25. A data communication system according to claim 24, wherein each of said plurality of processing units comprises:

a barrier network means;

a main storage;

a main control unit;

a scalar unit including a central processing unit for executing scalar computation and a cache memory;

a data transmission unit for transferring the processed data to and from said data communication network means;

a synchronous processing unit for executing synchronous control with said plurality of processing units based upon a sync signal transmitted via said barrier network means; and

an input/output unit for inputting and outputting the processed data to and from external equipment, respectively.

26. A data communication system according to claim 25, wherein each of said plurality of processing units further comprises a vector unit for executing vector computation.

27. A data communication system according to claim 16, wherein said data communication network means is a crossbar network including buffer memories.