JP2002244873A - Communication processing method and recording medium with communication processing program recorded thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a similar function to FORK of UNIX(R) by continuing communications by spontaneously rebuilding a communication line between a client-side process and a server side process (parent process) communicating via user-space direct transfer without an intervening OS, into a communication line between the client-side process and another server-side process (child process). SOLUTION: The communication processing method has a function where while a first process on a server side and a second process on a client side communicate via a first communication line, the first process requests suspension of the communication from the second process and the second process reports having suspended to the first process, a function where the first process requests the building of an interconnection via a second communication line from the second process and a third process on the server side generated by a process generating function, and a function where if the first process has already received data from the second process before the building of the connection, the data are copied into the third process. The second communication can thus succeed the first communication correctly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a communication processing method for emulating a fork in TCP / IP socket communication, and more particularly to an information processing system that performs user space transfer without the intervention of an OS. The present invention relates to a communication processing method in which a child process takes over a network connection between a parent process and a client.

[0002]

2. Description of the Related Art In a distributed information processing system of a server / client model, socket communication using TCP / IP is very common, and there are huge software resources. FIG. 2 shows an example of a server-client model information processing system. In this example, the host 210 and the host 260 are connected by the communication line 30, and the server application 211 and the client application 261 are connected.
Performs socket communication. In the conventional socket communication, a request from the process 262 of the client application 261 is transmitted to the parent process 2 of the server application 211.
12, the parent process 212 has a UNIX fo
A child process 213 is generated by the rk function, and the child process 213 processes a request from the process 262. However, in socket communication, since communication data is temporarily buffered in a buffer (buffer 231 or buffer 281) in the OS space, there is a limit to improvement in throughput. On the other hand, in recent years, VIA (Vir) that directly transfers data in the user space and does not need to copy the data to the OS space is required.
Tual Interface Architect
re) etc. are proposed. Known techniques include, for example, Steven H. Rodri
"High-Performance"
Local Area Communication
With Fast Socket ”(Procee
dings of the USENIX, 1997)
There is. According to this technology, it is possible to improve performance by connecting a server and a client on a high-speed network, and to emulate some functions of socket communication by the API of the high-speed network, thereby improving performance. Software assets can be used effectively. It is a well-known technique that this emulation can be realized by replacing the original function with a new function by the UNIX renaming function.

[0003]

As shown in FIG. 2, one of the end points in the socket communication is held by a process on the server side (host 210) (socket 221).
The other is held by the process on the client side (host 260) (socket 271). Fork on the server side
When the child process 213 is generated, the attribute of the socket held by the parent process is also copied to the child process, so that the parent process and the child process can share and use the same socket 221. That is, fork
The child process 213 generated by this can communicate with the client as it is. However, as shown in FIG. 3, in VIA, the end point (V
Actual Interface: hereinafter referred to as VI)
Are the local resources of each process, for
Even if a child process 313 is generated with k, there is a restriction that the VI 331 of the parent process 312 cannot be shared. For this reason, even if a child process is generated by fork, a problem arises in that a VI connection with the client cannot be established, and communication with the client cannot be performed. Therefore, VIA
In order to emulate the fork of the socket communication, it is necessary to establish a VI connection between the generated child process 313 and the client application 361 of the host 360. Further, depending on the application, communication may occur between the parent process 312 and the process 362 before a VI connection is established between the child process 313 and the process 362. In this case, the problem is to reliably transfer the communication generated between the parent process 312 and the process 362 between the child process 313 and the process 362. Therefore, one object of the present invention is to provide a FORM
The present invention provides a method in which a VI connection between a parent process of a server and a process of a client is replaced between a child process of a server and a process of a client so as to emulate the above, and the child process continues communication of the parent process. Further, another object of the present invention is to provide a parent process 312.
When the child process 313 has a shared memory area and communication occurs between the child process 313 and the process 362, the child process communicates between the parent process 312 and the client process 362 via the shared memory. It is to provide a method of utilizing communication.

[0004]

According to one aspect of the present invention, a process executed on a first information processing device and a process executed on a second information processing device are directly transferred to a user space. In an information processing system having a function of performing communication according to the first method, communication by a first connection between a first process on the first information processing device and a second process on the second information processing device is performed. The communication is continued by taking over by a second connection between a third process on the first information processing apparatus and the second process. Its features are a first function in which the first process and the second process interrupt communication through the first connection;
And the second function in which the second process newly establishes a second connection in response to a request from the first process, and the second connection causes the second connection in response to the request in the first process. And a third function of taking over communication by connection and continuing communication.

The third process is generated by a process generation function. Further, the first function is a function in which the first process issues a data transfer interruption request to the second process, and the second process responds to the first process in response to the interruption request. A function of interrupting the data transfer and notifying the first process of the interruption completion after the interruption is completed. Further, in another aspect of the present invention, in addition to the above, the second function is that the second or one of the third or both processes is performed when the second connection is established. It has the function of reporting to the process. The second function requests establishment of a second connection triggered by a spontaneous event occurring in the first process. Further, the second function requests the probability of the second connection in response to a sudden event occurring in the first process. Further, the third function is characterized in that the first process includes means for detecting and storing that the data reception processing has occurred in the first process before the second connection is established. Further, in the communication processing method according to the present invention, when the first process detects that the data reception process has occurred in the process before the second connection is established, the communication is notified to the third process. Means is provided. Further, the communication processing method of the present invention is characterized in that the second
When the first process detects that the data reception process has occurred in the process before the connection is established, and notifies the third process, the first process and the third process And means for emphasizing the copying of the data from the first process to the third process. Another aspect of the present invention is realized by an emulation library programmed to emulate the function of socket communication,
By executing the emulation library in each of the first information processing apparatus and the second information processing apparatus, a socket communication executed in each of the first information processing apparatus and the second information processing apparatus is performed. The communication can be performed without any change in the user program. According to another aspect of the present invention, the first
An information processing system having a function in which a process executed on one information processing device and a process executed on a second information processing device communicate with each other by direct transfer between user spaces. The third process on the first information processing device uses the communication through the first connection between the first process on the device and the second process on the second information processing device to A function of performing communication with the second process. In addition, the first process and the third process have a shared memory, and the shared memory has a request for data transfer from the third process to the second process. Area for the third process to notify the first process,
It has a point. Further, the first process and the third process have a shared memory, and on the shared memory,
It is characterized in that the first process has an area for notifying the third process that there is a data transfer request from the second process to the third process. Further, the first process and the third process have a shared memory, and the first process transfers data to be transferred from the second process to the third process on the shared memory. It has an area for storing.

Further, the first process and the third process have a shared memory, and data to be transferred from the third process to the second process is stored on the shared memory. The point is that one process has an area for storing.

[0007] Further, the first information processing apparatus and the second information processing apparatus are constituted by information processing apparatuses connected by a network.

According to another aspect of the present invention, the first information processing device and the second information processing device are constituted by a single information processing device.

[0009]

FIG. 1 shows a server / client system according to an embodiment of the present invention.

In FIG. 1, a server application 111 and a TCP are stored in a memory (not shown) of the host 110.
/ IP socket emulator module 120, VIA
A module 130 is stored. Also host 160
A client application 161, a TCP / IP socket emulator module 170, and a VIA module 180 are stored in a memory (not shown) of the same. The host 110 and the host 160 are connected via the network 1, and the server application 111 and the client application 161 communicate with each other via a communication line (1
0, 20) to perform communication by transmitting and receiving packets. TC
The P / IP socket emulator modules 120 and 170 include a function group emulating the function of the TCP / IP socket communication by the API of the VIA in the same manner as the above-mentioned known example. In particular, regarding the function group shown in FIG.
The function is emulated by adding a function for realizing the present invention in addition to the function inherent in the function. VIA modules 130 and 180 are VIA drivers (not shown)
Contains. Also, VIs (131, 132, 181, and 182), which are end points of a communication line based on the VIA, are configured.
Parent process 11 in server application 111
2 generates a child process 115 by using EMU_FORK () F1 indicated by reference numeral F1 in FIG. 10 that emulates FORK (). In the EMU_FORK () F 1, the parent process 112 and the child process 115 generate a shared memory 117 for performing a process-to-process communication in the function of generating a child process. A function of generating the occurrence flag 140 has been added. Also, in the parent process 112, the data received flag 113, the replacement completion flag 123, and the replacement request monitoring thread 114
Generate Further, the re-scheduling request monitoring thread 116 and the copy request monitoring thread 14
1 is generated. The transfer request flag P118 is written by the parent process 112, and the writing is monitored by the transfer request monitoring thread 116. Copy occurrence flag 14
0 is written by the parent process 112 and the copy request monitoring thread 141 monitors the writing. The relocation request flag C119 is written by the child process 115, and the rewriting request monitoring thread 114 monitors the writing. In the client application 161, the process 162 emulates CONNECT () and the EMU_CONN indicated by reference numeral F2 in FIG. 10.
ECT () is used to request the server application 111 to establish a communication line. EMU_CONNECT
T () F2 has a function of generating an interrupt request flag 163 and an interrupt request monitoring thread 164 in the process 162 when the connection is permitted. The interruption request flag 163 is written by a packet sent from the server application 111, and the writing is monitored by the interruption request monitoring thread 164. FIGS. 4, 5 and 6 illustrate the parent process 112 and the child process 11 in this embodiment.
5 and a flowchart showing the processing procedure of a process 162, respectively. Hereinafter, the details of the VI reassignment process will be described with reference to the drawings. First, the processing flow of the parent process 112 will be described with reference to the flowchart shown in FIG. In step S2, the parent process 112 listens for a connection request from the process 162 on the client application 161. Next, in step S3, connection permission is issued in response to a connection request from the process 162. Next, step S
In step 4, a child process is generated by EMU_FORK () F1. In step S5, it is checked whether the VI has already been replaced by looking at the replacement completion flag 123. The reassignment completion flag 123 is written in step S13. If the replacement has already been performed (when the replacement completion flag 123 is 1), the process proceeds to step S14. When the re-transfer has not been performed (re-transfer completed flag 1
If (23 is 0), the process proceeds to step S6. Step S6
Then, the parent process 112 checks whether or not a VI reconnection request trigger has occurred in its own process. The child process has been created in step S4, but at that time (step S4).
In 4), VI reassignment is not yet performed. Because VI
Is a costly process involving a great deal of overhead, and even if a child process is created, the child process does not necessarily communicate with the client.
Therefore, as shown in FIG. 7, an event that actually causes communication between the child process 115 and the process 162 is generated by V
This is used as a trigger to start the I reassignment process. In FIG. 7, the trigger T1 is the CLO of the communication line 10 by the parent process 112.
SE. The trigger is a spontaneous trigger. After CLOSE of the communication line 10, the communication partner of the process 162 becomes the child process 115. Trigger T2 is the parent process 112
Is annihilation. The trigger may be spontaneous or sudden. After the extinction, the child process 115 must be in a communicable state. The trigger T3 is the occurrence of the receiving operation (RECV) of the child process 115. The trigger is a spontaneous trigger. Since the child process 115 expects communication from the process 162, the child process 115 must be in a communicable state. The trigger T4 is a transmission operation of the child process 115 (S
END). The trigger is a spontaneous trigger. The child process 115 must be communicable to transmit data to the process 162. In step S6, if the trigger has not been generated, the parent process 112 proceeds to step S14 to continuously execute the server program. When the trigger is generated in step S6, the normal process executed by the parent process 112 is temporarily stopped, and the process proceeds to step S7 which is a routine of the VI reconnection process. In step S7, the parent process 112 requests the process 162 to suspend the data transfer. Thereafter, in step S8, a data transfer interruption completion report from the process 162 is waited for. If there is a data transfer interruption completion report, the parent process proceeds to step S9, and checks whether or not communication has occurred between the parent process 112 and the process 162 before the VI reconnection and the parent process 112 has already received data. The check is performed by looking at the data already received flag 113. The data received flag 113 is written in step S16. When the data has already been received (when the data already received flag 113 is 1), the process proceeds to step S10. If data has not been received (the data received flag 113 is 0), the process proceeds to step S11. In step S10, the parent process 112 sets the copy occurrence flag 1
40 is set to notify the child process 115 of the occurrence of data copy. Subsequently, the parent process 112 and the child process 115
Emphasizes that the address space of the parent process 112 is copied to the child process 115, and the data already received by the parent process 112 is succeeded to the child process 115 without omission. In step S11, a request is made to the child process 115 and the process 162 to transfer the VI to each other.
The parent process 112 and the child process 115 are shared memory 11
7, and sets the relocation request flag P118 to request the child process 115 to reconnect the VI. The parent process 112 and the process 162 are connected to the communication line 10
The parent process 112 transmits a VI reassignment request packet to the process 162 and sets the reassignment request flag 163 to request the VI reassignment. In step S12, the process waits for a re-completion report from the process 162. In step S13, the reassignment completion flag 123 is set. By setting the refill completion flag 123,
Thereafter, even if an event for issuing a reassignment request trigger occurs, it is prevented that a reassignment request is issued twice. In step S14, when returning from the VI reconnection process routine, the process of the parent process 112 that has been suspended is restarted, and otherwise, normal processing is executed. Step S
At 15, it is checked whether or not data from the process 162 has been received in the normal processing of the parent process 112. This process emulates RECV ().
Is executed in EMU_REDV () F5 shown in FIG.
If data reception has occurred in step S15, the process proceeds to step S16. If the data has not been received, the process proceeds to step S17. In step S16, the data reception flag 113 is set. Data already received flag 113
The parent process 112 knows that the reception of data to be copied to the child process 115 has occurred. In step S17, it is checked whether or not the normal process of the parent process 112 ends.
If the process is to be ended, the process proceeds to step S18, and the process ends. If not, the process proceeds to step S5 again, and the previous steps are repeated. The above is the operation of the parent process 112 at the time of VI reconnection. Next, the processing flow of the child process 115 will be described with reference to the flowchart shown in FIG. In step S21, the child process 115 is generated by EMU_FORK () F1, and the process is started. In step S22, the child process 115 checks whether a VI reconnection request trigger has occurred in itself.
If the trigger T3 or the trigger T4 has occurred in step S22, the process proceeds to step S23. If the trigger has not been generated, the process proceeds to step S26. Step S23
Then, the child process 115 sets the reassignment request flag C119 and reports to the parent process 112 that the reassignment request trigger has occurred in the child process 115. The parent process 112 sets the replacement request flag C119 to the thread 11
4 to monitor the occurrence of the trigger. In step S24, the child process 115 checks whether there is a data copy request from the parent process 112. The check is performed by the copy request monitoring thread 141 by the copy occurrence flag 140.
It is done by monitoring. When there is a data copy request in step S24 (when the copy occurrence flag 140 is 1), the normal process executed by the child process 115 is temporarily suspended, and the process proceeds to step S25. Step S
If there is no data copy request at 24 (when the copy occurrence flag 140 is 0), the process proceeds to step S26. In step S25, the child process 115 becomes the parent process 112.
Is copied to the child process 115. In step S26, the child process 115 becomes the parent process 112.
Is checked for a VI reconnection request. The check is performed by the thread 116 by the rescheduling request flag P118.
It is done by monitoring. If there is a transfer request in step S26 (when the transfer request flag P118 is 1), step S, which is a routine of the VI transfer process, is performed.
Proceed to 25. If there is no change request in step S26 (if the change request flag P118 is 0), the process proceeds to step S29. In step S27, the child process 115
Is the process 1 on the client application 161
Listen for a connection request from 62. In step S28, the child process 115 issues a connection permission in response to a connection request from the process 162. In step S29, when returning from the VI reconnection processing routine, the processing of the suspended child process 115 is restarted, and otherwise, normal processing is executed. In step S30, it is checked whether or not the child process 115 ends in the normal processing. When ending, the process proceeds to step S31, and the process ends. If not, the process proceeds to step S22 again and repeats the previous steps. The above is the operation of the child process 115 at the time of VI reconnection. Finally, the flow of the process 162 will be described with reference to the flowchart shown in FIG. The process 162 started in step S41 is executed by the parent process 112 in step S42.
Make a connection request. The process 162 waits for the connection to be permitted in step S43. In step S44, it is checked whether there is a data transfer interruption request from the parent process 112. This check is performed by monitoring the suspension request flag 163 by the suspension request monitoring thread 164.
If there is an interruption request in step S44 (if the interruption request flag 163 is 1), the normal processing executed by the process 162 is temporarily suspended, and the process proceeds to step S45. If there is no interruption request in step S44 (if the interruption request flag 163 is 0), the process proceeds to step S52. In step S45, processing for interrupting data transfer is performed. In step S46, it is checked whether or not the data transfer interruption has been completed. If not, step S4
Return to 5. If it has been completed, the process proceeds to step S47. In step S47, a data transfer interruption completion report is made to the parent process 112 by packet communication. Step S4
In step 8, the process 162 checks whether or not there is a VI reconnection request from the parent process 112. This check is performed by monitoring the reassignment request flag 163 by the thread 164. If there is a relocation request in step S48 (if the relocation request flag 163 is 1), the normal processing being executed by the process 162 is temporarily suspended, and VI
The process proceeds to step S49, which is a routine of the replacement process. If there is no relocation request in step S48 (if the relocation request flag 163 is 0), the process proceeds to step S52.
In step S49, the process 162 is a child process 115
Request a VI connection. Next, in step S50, the process waits until the connection is permitted. When the connection is permitted, the process 162 reports to the parent process 112 that the VI reassignment has been completed in step S51. This report is made by transmitting a retransmission completion report packet to the parent process 112 and setting a relocation completion flag 123. Next, in step S52, when the process 162 returns from the VI reconnection process routine, the process of the suspended process 162 is restarted, and otherwise, the normal process is executed. In step S53, it is checked whether or not the process ends in the normal process of the process 162. When ending, the process proceeds to step S54, and the process ends. If not, the process proceeds to step S44 again and repeats the previous steps. The above is the operation of the process 162 at the time of VI reconnection. How the respective processes of the parent process 112, the child process 115, and the process 162 described above operate as a whole in chronological order will be described with reference to a time chart shown in FIG. First, at time point a, the client issues a connection request 910 to the parent process on the server,
The parent process receives it at time A. In the figure, the words in parentheses described at the beginning of the processing name indicate whether the processing target for the client is a parent process or a child process on the server. The same applies hereinafter. Subsequently, the parent process permits the client to connect 9 at time B.
11 and the client receives it at time b. At time X, the parent process is EMU_FOR
A child process is created by K () 918. At time C, the parent process issues a data transfer suspension request 912 to the client, and the client receives it at time c. After the time point c, the client performs a data transfer interruption process (not shown), and at the time point d when the interruption process is completed, an interruption completion report 913 to the parent process.
Issue The parent process reports the interruption completion report 9 at time D.
13 and then, at time Y, copy 922 the already received data to the child process. Subsequently, at time E, the parent process issues a reassignment request 914 to the client, and the client receives it at time e. At time f, the client issues a connection request 915 to the child process, and the child process receives it at time F. Subsequently, at time point G, the child process grants the client 91
6 and the client receives it at time g. Finally, at time point h, the client issues a relocation completion report 917 to the parent process, and the parent process receives it at time point H, and a series of VI relocation processing is completed. Here, the parent process is in a data receivable state after time B, and the child process is in a data receivable state after time G. The time between the time bc and the time after the time h is the data transmittable time of the client, and the time d
The interval between g is the transmission suspension time. If the client starts transmitting data at time b, the parent process can receive the data at time B '. However, by receiving the suspension completion report 913, the parent process knows that no data has been received since time D. Therefore, the time during which the parent process may receive the data before the VI reassignment is between the time points B′D,
If data is received during that time, the data is copied to the child process. As a result, it becomes possible for the child process to correctly take over the communication of the parent process after the VI reconnection is completed. On the other hand, FIG. 8 is a time chart when the data transfer is not interrupted. FIG. 8 shows the effectiveness of the present invention. First, similarly to FIG. 9, the parent process is in a data receivable state after time B, and the child process is in a data receivable state after time G. The time between the time points bc and after the time point h is the data transmittable time of the client, and the time point between the time points dg is the transmission suspension time. However, the parent process cannot know the time point E 'when the client interrupts the transmission and it is reflected on the server side.
That is, the parent process cannot know how long data from the client will be transmitted. Therefore, the parent process does not know when to copy the received data to the child process, and cannot guarantee that the copying is performed correctly. On the other hand, in the present embodiment, as described above with reference to FIG. 9, the parent process on the server issues a data transfer suspension request to the process on the client, and the completion of suspension is returned from the client side. It can be seen that the received data should be copied to the child process. Therefore, it is ensured that communication is correctly continued when VI reconnection is performed. In the embodiment described above, communication between processes is executed using the shared memory, but other means such as PIPE may be used. Although communication between the hosts is performed by packet communication, other means may be used. Further, the first host and the second host do not need to be physically separated, and it is obvious that the present invention is also applied to a process executed on the same information processing apparatus. Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 11, a server application 1111 and a T
CP / IP socket emulator module 1120,
The VIA module 1130 is stored. Host 1
The parent process 1112 of 110 communicates with a process on a client host (not shown) having the same configuration as the host 360 of FIG. 3 by a method emulating socket communication. In this case, the child process 1113 that does not have a communication resource for communication with the client host communicates with the client host in the following manner. Reference numeral 1140 on the server application is a shared memory shared by the parent process 1112 and the child process 1113. On the shared memory 1140, the child process 1113
2, a transmission request flag for notifying the client host to receive data from the client host, a transmission request flag for notifying the client host to transmit data, and a transmission request flag for storing transmission / reception data. Data buffer 1143 and parent process 1112
A data reception flag 1144 for notifying the child process 1113 that the data to the child process 1113 has been received from the client host, and informing the child process 1113 that the parent process 1112 has transmitted the data from the child process 1113 to the client host. There is an area for a data transmission flag 1145 for notification. Shared memory 11
40 is created at the same time when the parent process 1112 generates the child process 1113 by FORM (). First, a case where the child process 1113 corresponding to the RECV of the socket communication receives data from the client process will be described. When the child process 1113 receives data from a client, it sets a reception request flag 1141. The parent process 1112 constantly monitors the reception request flag 1141, and upon detecting that the reception request flag 1141 has been set, enters a state of waiting for data reception from the process of the client host. When the parent process 1112 receives the data, the parent process 1112 copies the data to the data buffer 1143 and subsequently sets a data reception flag 1144. The child process 1113 constantly monitors the data reception flag, and upon detecting that the data reception flag 1144 has been set, copies the data in the data buffer 1143 and completes the data reception. Next, a case where data is transmitted from the child process 1113 to the client process, which corresponds to SEND of socket communication, will be described. Child process 1113
When transmitting data to the client, first, the data to be transmitted is copied to the data buffer 1143, and then the transmission request flag 1142 is set. Parent process 1112
Monitors the transmission request flag 1142 at all times, and when it detects that the transmission request flag 1142 has been set, the data buffer 1143 is transmitted to the client host process.
Is transmitted, and when transmission is completed, a data transmission flag 1145 is set. The child process 1113 constantly monitors the data transmission flag 1145, and
When it is detected that 145 has been set, the data transmission is completed. In the second embodiment described above, only the method of emulating RECV and SEND of socket communication has been described. However, any communication that occurs between the server application and the client application shares the corresponding flag and data area. It is obvious that emulation is possible by having it on the memory. Further, it is obvious that the present invention is applicable even if the server application and the client application are physically separated from each other and are executed on a host connected by a network, or are executed on the same information processing apparatus. It is. Further, the number of child processes on the server application does not need to be limited to one. Even when there are a plurality of child processes, the parent process and the child process each have a shared memory, and each shared memory has a shared The present invention is applied by identifying by an identifier. The solution to the synchronization problem that occurs in communication using a shared memory is a known technique.

[0011]

As described above, according to the present invention, a communication line between a client-side process and a server-side process (parent process) performing communication by user space direct transfer without the intervention of an OS. Can be spontaneously replaced by a communication line with another process (child process) on the server side to continue the communication and realize the same function as UNIX FORK (). Further, according to the second embodiment of the present invention, by using the shared memory, the process on the parent client side and the process on the parent side can be performed without changing the communication line between the process on the client side and the child process on the server side. Allows the child process to communicate with the client-side process.

[Brief description of the drawings]

FIG. 1 is a block diagram of a server-client system according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing the concept of socket communication in general TCP / IP.

FIG. 3 is a block diagram showing a state of communication in a server / client system that communicates by direct user space transfer.

FIG. 4 is a flowchart illustrating processing of a parent process on the server side when a communication path is switched in the embodiment.

FIG. 5 is a flowchart illustrating processing of a child process on the server side when a communication path is switched in the embodiment.

FIG. 6 is a flowchart illustrating processing of a process on the client side when a communication path is switched in the embodiment.

FIG. 7 is a diagram showing an event serving as a trigger for changing a communication channel in the embodiment.

FIG. 8 is a time chart showing the progress of processing when the parent process on the server side does not request the process on the client side to interrupt the data transfer when the communication path for comparison with the embodiment is changed.

FIG. 9 is a time chart showing the progress of a process when changing a communication channel according to the embodiment.

FIG. 10 is a diagram showing functions added to original processing when emulating socket communication in the embodiment.

FIG. 11 is a view showing the concept of a shared memory shared between a child process and a parent process in order for a child process to communicate with a client-side process in the second embodiment.

[Explanation of symbols]

1: Network, 10, 20: Communication line, 110, 1
60 ... host, 111 ... server application, 11
2 ... parent process, 116 ... child process, 120, 170
... TCP / IP socket communication emulator block, 1
30, 180... VIA module, 131, 132, 1
81, 182... VI, 161... Client application, 162.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsuneyuki Imaki 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. F-term in Hitachi Central Research Laboratory (Reference) 5B045 BB42 GG01 5B089 GA02 GB01 GB09 JA11 KG03 KG06 5B098 AA10 GA04 GC16 5K034 FF01 KK27 KK28 LL01 LL02

Claims (24)

[Claims] An information processing system having a function in which a process executed on a first information processing device and a process executed on a second information processing device communicate with each other by direct transfer between user spaces. Communication between a first process on the first information processing device and a second process on the second information processing device by a first connection is performed by a first connection on the first information processing device. 3. A communication processing method for continuing communication by taking over a second connection between a third process and the second process, wherein the first process and the second process perform communication by the first connection. A second step in which the third process and the second process newly establish a second connection in response to a request from the first process; and On request Communication processing method 2 connection and having a third step to continue communication takes over the communication by the first connection. 2. The communication processing method according to claim 1, wherein said third process is generated by a process generation function. 3. The first step is that the first process issues a data transfer interruption request to the second process, and the second process responds to the interruption request by the first process. 2. The communication processing method according to claim 1, further comprising the steps of: interrupting data transfer to the process; and performing an interrupt completion report to the first process after the interrupt is completed. 4. The first process stores the fact that a data reception process has been performed after an interruption request has been made to the second process, and receives the data reception process after receiving the interruption completion report. 4. The communication processing method according to claim 3, wherein the copied data is copied to the third process. 5. The second step, wherein either or both of the second process and the third process report that the second connection has been established to the first process. The communication processing method according to claim 1, further comprising a procedure. 6. The method according to claim 1, wherein the request for establishing the second connection in the second step is triggered by a spontaneous event occurring in the first process. Communication processing method. 7. The method according to claim 1, wherein the request for establishing the second connection in the second step is issued when an unexpected event occurs in the first process. Communication processing method. 8. The method according to claim 1, wherein said first connection is established until said second connection is established.
2. The communication processing method according to claim 1, wherein said process detects and stores that a data reception process has occurred in said process. 9. The method according to claim 1, wherein said first connection is established before said second connection is established.
9. The communication processing method according to claim 8, wherein when said process detects that a data reception process has occurred in said process, said process is notified to said third process. 10. The method according to claim 1, wherein the first process detects that a data reception process has occurred in the process before the second connection is established, and notifies the third process of the first process. 9. The communication processing method according to claim 8, wherein said process and said third process emphasize and copy said data from said first process to said third process. 11. The communication processing method according to claim 1, wherein the first connection is disconnected after the establishment of the second connection is completed. 12. A first information processing device and a second information processing device interconnected by a network, wherein a process executed on the first information processing device and a second information processing device are executed. In an information processing system having a function in which processes executed on each other perform communication by direct transfer between user spaces, the first process and the second process interrupt communication by the first connection. 1 means;
The second process establishes a second connection newly by the third process and the second process in response to a request from the first process.
An information processing system, comprising: a third means for, when requested by the first process, the second connection taking over the communication by the first connection and continuing the communication. 13. A communication processing method according to claim 1, wherein said communication processing method is realized by an emulation library programmed to emulate a function of socket communication, and said first information processing apparatus and said second information processing apparatus respectively execute said emulation library. The communication is enabled without any change in a user program for socket communication executed in each of the first information processing device and the second information processing device by executing the emulation library. Communication processing method described. 14. Communication between a first process on a first information processing device and a second process on the second information processing device by a first connection is performed by the first information processing device. A communication processing method for taking over a second connection between a third process and the second process above to continue communication, wherein the first process and the second process are the first process. A first step of interrupting communication by a connection, a second step of newly establishing a second connection by the third process and the second process in response to a request of the first process, According to the requirements of the second process,
And a third step of continuing the communication by taking over the communication by the first connection. 3. A computer-usable recording medium in which an emulation library for executing a communication processing method is recorded. 15. The communication processing method according to claim 1, wherein said first information processing device and said second information processing device are constituted by a single information processing device. 16. The first process stores that a data reception process has been performed after an interruption request has been made to the second process, and receives the data reception process after receiving the interruption completion report. 10. The communication processing method according to claim 9, wherein the first process and the third process have a shared memory space in order to copy the obtained data to the third process. 17. An information processing system having a function in which a process executed on a first information processing device and a process executed on a second information processing device communicate with each other by direct transfer between user spaces. Using communication by a first connection between a first process on the first information processing device and a second process on the second information processing device, Wherein the third process has a function of communicating with the second process. 18. The first process and the third process have a shared memory, and there is a data transfer request from the second process to the third process on the shared memory. 18. The communication processing method according to claim 17, wherein the first process has an area for notifying the third process of the fact. 19. The first process and the third process have a shared memory, and there is a data transfer request from the third process to the second process on the shared memory. The communication processing method according to claim 17, wherein the third process has an area for notifying the first process of the fact. 20. The first process and the third process have a shared memory, and data to be transferred from the second process to the third process is stored on the shared memory. 18. The communication processing method according to claim 17, wherein one process has an area for storing. 21. The first process and the third process have a shared memory, and data to be transferred from the third process to the second process is stored on the shared memory. 18. The communication processing method according to claim 17, wherein one process has an area for storing. 22. The communication processing method according to claim 17, wherein the first information processing device and the second information processing device are configured by an information processing device connected by a network. 23. The communication processing method according to claim 17, wherein the first information processing device and the second information processing device are constituted by a single information processing device. 24. An information processing system having a function in which a process executed on a first information processing apparatus and a process executed on a second information processing apparatus communicate with each other by direct transfer between user spaces. Using communication by a first connection between a first process on the first information processing device and a second process on the second information processing device, A computer-usable recording medium in which a communication processing method in which the third process communicates with the second process is recorded.