JP7475311B2 - A device for determining the bandwidth to be set in a network - Google Patents

Description

The present invention relates to a technology for shortening the processing time when a specific process is distributed and performed by multiple computers.

In order to shorten the processing time of machine learning that is performed by repeatedly using a large amount of training data, it has been proposed to divide the machine learning processing into multiple jobs and distribute the processing of the multiple jobs among multiple computers. In distributed processing, since the results of a job performed by one computer are required by other computers, the multiple computers are configured to be able to communicate with each other via a network. Here, the network may be, for example, an electrical network composed of routers, switches, etc. The network may also be an optical network composed of optical cross-connects, etc. Furthermore, the network may be a combination of an electrical network and an optical network. Each computer sends and receives data obtained as a result of a job (hereinafter referred to as result data) via the network.

In order to efficiently send and receive result data between computers, Non-Patent Document 1 discloses the use of an orchestrator. According to Non-Patent Document 1, the orchestrator determines the bandwidth required for sending result data for each schedule period, and determines the set bandwidth for sending result data based on the determined bandwidth. Then, before the next schedule period, the orchestrator notifies the network control device of the set bandwidth for sending each result data determined for the next schedule period. In accordance with the notification from the orchestrator, the network control device controls the network so that the set bandwidth determined by the orchestrator is set between computers during the next schedule period.

Cen Wang, et al. , "Analysis of the Optical Data Center Network Slicing Strategy in Support of Machine Learning Applications with Multiple Patterns", iPOP2020, T3-1, September 11, 2020

When a computer executes a job that requires result data sent from another computer, the computer cannot start the job until it has received the result data from the other computer. If the acquisition of such result data is delayed, the computer will be forced to wait for the result data to be received, which means a waiting time will occur.

Non-Patent Document 1 determines the set bandwidth based only on the amount of result data. Therefore, multiple wait times occur on each computer, which can increase the processing time of machine learning.

The present invention provides a technology for shortening the processing time when a specific process is distributed and performed by multiple computers.

According to one aspect of the present invention, in a system in which a predetermined process is divided into a plurality of jobs and each of the plurality of jobs is assigned to each of a plurality of computers connected to a network, a source computer among the plurality of computers that has executed an assigned job sets the result data resulting from the job on the network in order to transmit the result data to a destination computer that uses the result data, and a determination device that determines the set bandwidth of a path from the source computer to the destination computer includes a first determination means that determines first task information of an uncompleted first transmission task, and each of the first transmission task information indicates the remaining data amount RV of the result data, the remaining time RT until the transmission of the result data is completed, and the source computer and destination computer of the result data, and the first determination means that determines the remaining data amount RV of the result data for each of the first transmission tasks, and the remaining data amount RT of the result data for each of the first transmission tasks. The system includes a second determination means for determining a required bandwidth RBW based on the amount of data RV and the remaining period RT, and a determination means for performing a determination process for determining a set bandwidth SBW to be assigned to each of the first transmission tasks during an allocation period of time T, and updating the remaining data amount RV and the remaining period RT for each of the first transmission tasks. In the determination process for the first allocation period, the determination means selects a second transmission task to be processed from the first transmission task in descending order of priority, and determines whether a path with a bandwidth ABW equal to or greater than the required bandwidth RBW of the second transmission task from the source computer of the second transmission task to the destination computer can be set in the network. If the bandwidth ABW is settable, the bandwidth ABW is determined to be the set bandwidth SBW of the second transmission task, and if the bandwidth ABW is not settable, the maximum bandwidth that can be set in the network is determined to be the set bandwidth SBW of the second transmission task.

This invention makes it possible to reduce the processing time required when performing a given process in a distributed manner across multiple computers.

FIG. 1 is a configuration diagram of a system according to an embodiment. 11 is a flowchart of a process performed by a determination device according to an embodiment. 4 is a time chart of a process performed by a determination device according to an embodiment. 11 is a flowchart of an uncompleted transmission task determination process according to an embodiment. 11 is a flowchart of a necessary band determination process according to an embodiment. 11 is a flowchart of a decision process according to one embodiment. FIG. 2 is a functional block diagram of a decision device according to an embodiment.

The embodiments are described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. In addition, the same reference numbers are used for the same or similar configurations, and duplicate descriptions are omitted.

Figure 1 is a configuration diagram of a system for performing a specified process. The specified process is, for example, a machine learning process. However, the content of the specified process may be a process different from the machine learning process. The processing system has a scheduling device 1. The scheduling device 1 is a management device that divides the specified process into multiple jobs, manages the schedules of these jobs (job schedules), and assigns each job to one of multiple computers 5 in accordance with the job schedule. The multiple computers 5 are connected to a network 4.

The scheduling device 1 also determines, based on the job schedule, which computers 5 (destination computers 5) require result data of a job executed by a certain computer 5 (source computer 5). The number of destination computers 5 is not limited to one, and there can be multiple destination computers 5. The scheduling device 1 manages the process of transmitting result data obtained by one source computer 5 to one destination computer 5 as one transmission task. In other words, if a certain computer 5 needs to transmit result data to four other computers 5, four transmission tasks are generated. The scheduling device 1 also determines the deadline for each transmission task based on the job schedule. Furthermore, the scheduling device 1 determines which transmission tasks have completed transmission of result data based on information from multiple computers 5.

When result data to be transmitted occurs, resulting in a new transmission task, the scheduling device 1 notifies the determination device 2 of transmission task generation information. The generation information is information indicating the identifier of the source computer 5 (hereinafter simply referred to as the source) of the result data to be transmitted in the newly generated transmission task, the identifier of the destination computer 5 (hereinafter simply referred to as the destination), the amount of data, and the deadline for the transmission task. In addition, when a completed transmission task occurs, the scheduling device 1 notifies the determination device 2 of completion information. The completion information is information indicating the completed transmission task.

The determination device 2 determines the currently ongoing transmission task (uncompleted transmission task) from the occurrence information and completion information notified by the scheduling device 1. The determination device 2 determines the set bandwidth SBW for each uncompleted transmission task based on its deadline and the remaining amount of data that has not been transmitted, and notifies the network control device 3 of the source, destination, and the determined set bandwidth SBW for each uncompleted transmission task. The network control device 3 controls the network 4 to set a path of the set bandwidth SBW from the source to the destination on the network 4 for each uncompleted transmission task.

The network 4 may be, for example, a circuit-switched network. The network 4 may also be, for example, a packet-switched network. The network 4 may also be an electrical network that conveys information by electrical signals. The network 4 may also be an optical network that conveys information by optical signals. For example, if the network 4 is a circuit-switched electrical network, the network 4 may be composed of electrical signal cross-connects. For example, if the network 4 is a packet-switched electrical network, the network 4 may be composed of routers, switches, etc. For example, if the network 4 is a circuit-switched optical network, the network 4 may be composed of optical cross-connects, etc. For example, if the network 4 is a packet-switched optical network, the network 4 may be composed of optical packet switches, etc.

When network 4 is a circuit-switched type, the path between computers from the sender to the destination is a so-called physical path, and communication resources for transmitting data from the sender to the destination at the set bandwidth SBW are always allocated exclusively to the sender and the destination. On the other hand, when network 4 is a packet-switched type, the path between computers from the sender to the destination is a so-called virtual path, and no communication resources are always reserved from the sender to the destination, but the set bandwidth SBW is secured by packet flow control.

The granularity of the bandwidth that can be set (used) in the network 4 varies depending on the type of the network 4. In general, when the network 4 is a circuit-switched network, the granularity of the available bandwidth is coarser than that of a packet-switched network. As an example, when the network 4 is a circuit-switched network, the available bandwidth may be an integer multiple of 64 kbps, an integer multiple of 1.5 M, or an integer multiple of 150 M. In the following description, the bandwidth that can be used in the network 4 is referred to as the available bandwidth. The set bandwidth SBW is selected from one or more available bandwidths. When the network 4 is a circuit-switched optical network and a wavelength path from a sender to a destination is set in the network 4, the transmission speed of the resultant data transmitted through the wavelength path is not determined by the network 4 but by the optical modulation method used by the computer 5. In the present invention, the available speed of such a wavelength path is treated as infinity in the determination device 2.

Figure 2 is a flowchart of the process executed by the determination device 2 to determine the set bandwidth SBW for the uncompleted transmission task. The process of Figure 2 is executed for each processing period of Figure 3. Specifically, the determination device 2 executes the process of Figure 2 in the processing period n based on the occurrence information and completion information received from the scheduling device 1 in the collection period n of Figure 3, and determines the set bandwidth SBW for each uncompleted transmission task. Then, the determination device 2 notifies the network control device 3 of each set bandwidth SBW determined in the processing period n so that each set bandwidth SBW is set in the allocation period n. The start timing of the allocation period n is later than the completion timing of the processing period n in consideration of the time required for the network control device 3 to change the configuration of the network 4. The process in the processing period n will be described below with reference to Figure 2.

First, in S10, the determination device 2 performs an uncompleted transmission task determination process to determine an uncompleted transmission task and its task information based on the occurrence information and completion information notified from the scheduling device 1 during collection period n. The task information of an uncompleted transmission task includes information indicating the source, destination, remaining period RT, and remaining data amount RV of the uncompleted transmission task. Note that the determination device 2 holds the task information of each uncompleted transmission task at the end of processing period n-1 as a result of processing during processing period n-1.

Figure 4 is a flowchart of the incomplete transmission task determination process. First, in S20, the determination device 2 adds the transmission task indicated in the occurrence information received during the collection period n to the incomplete transmission task at the end of the processing period n-1 as an incomplete transmission task, and generates task information for the added incomplete transmission task. Note that the determination device 2 sets the period from the start timing of the allocation period n to the deadline of the transmission task indicated in the occurrence information as the remaining period RT of the incomplete transmission task to be added. The determination device 2 also sets the amount of result data of the transmission task indicated in the occurrence information as the remaining data amount RV of the incomplete transmission task to be added. Furthermore, the determination device 2 sets the identifiers of the computers 5 indicated as the source and destination indicated in the occurrence information as the source and destination of the incomplete transmission task.

In S21, the determination device 2 deletes completed transmission tasks from the uncompleted transmission tasks based on the completion information received in the collection period n. Then, in S22, if there is an uncompleted transmission task with RT≦0 among the uncompleted transmission tasks, the determination device 2 changes the RT of the uncompleted transmission task to a period T equal to the allocated period length. A transmission task with RT≦0 and whose completion has not been notified in S21 is a transmission task that was not completed by the deadline notified by the scheduling device 1. The process of S22 corresponds to a process of extending the remaining period RT of a transmission task that was not completed by the deadline notified by the scheduling device 1 to the end timing of the allocated period n.

Returning to FIG. 2, when the task information of each of the uncompleted transmission tasks is generated by the uncompleted transmission task determination process, the determination device 2 performs a necessary bandwidth determination process to determine the necessary bandwidth for each of the uncompleted transmission tasks in S11. FIG. 5 is a flowchart of the necessary bandwidth determination process. In S30, the determination device 2 obtains the necessary bandwidth RBW for each of the uncompleted transmission tasks as RV/RT. That is, the necessary bandwidth RBW of the uncompleted transmission task is the bandwidth required to transmit the remaining data amount RV of the uncompleted transmission task in the remaining period RT. Next, in S31, the determination device 2 determines the priority of the uncompleted transmission task based on the necessary bandwidth RBW of the uncompleted transmission task. Specifically, in this embodiment, the determination device 2 increases the priority as the necessary bandwidth RBW is larger. Note that, when there are multiple uncompleted transmission tasks with the same necessary bandwidth RBW, the priority of the multiple uncompleted transmission tasks with the same necessary bandwidth RBW can be determined by any method. As an example, when there are multiple uncompleted transmission tasks with the same necessary bandwidth RBW, the configuration can be such that the priority is increased as the remaining period RT is shorter. This priority defines the order in which the decision process is performed in S12 of Figure 2.

Returning to FIG. 2, the determination device 2 performs the determination process in S12. FIG. 6 is a flowchart of the determination process. In S40, the determination device 2 selects the highest priority uncompleted transmission task among the uncompleted transmission tasks that have not been processed in FIG. 6 as the processing target. Then, the determination device 2 determines the available bandwidth ABW that is equal to or greater than the required bandwidth RBW of the uncompleted transmission task to be processed among one or more available bandwidths that are available (settable) in the network 4. Note that, if there are multiple available bandwidths ABW that are equal to or greater than the required bandwidth RBW of the uncompleted transmission task to be processed, the determined available bandwidth ABW is the smallest of them. In S41, the determination device 2 determines whether or not the path of the determined available bandwidth ABW from the source to the destination of the uncompleted transmission task to be processed can be set in the network 4. In other words, the determination device 2 determines whether or not communication resources remain in the network 4 for setting the path of the determined available bandwidth ABW from the source to the destination of the uncompleted transmission task to be processed. The determination device 2 holds configuration information of the network 4, and determines whether or not a path of the available bandwidth ABW can be set based on the configuration information. In doing so, the determination device 2 takes into account the set bandwidth SBW already assigned to the uncompleted transmission task that has been processed. As described above, when the network 4 sets a wavelength path, the determination device 2 treats the available bandwidth ABW as infinity, so that if there is an allocatable wavelength path, the determination in S41 is always Yes, and if there is no allocatable wavelength path, the determination in S41 is always No.

If it is possible to set, the determination device 2 determines the determined available bandwidth ABW as the set bandwidth SBW of the uncompleted transmission task to be processed in S42. Thereafter, the determination device 2 updates the remaining period RT of the uncompleted transmission task to be processed to RT-T and updates the remaining data amount RV to RV-SBW x T in S43. On the other hand, if it is determined in S41 that it is not possible to set, the determination device 2 determines the settable maximum bandwidth SBW < RBW as the set bandwidth SBW of the uncompleted transmission task to be processed in S45, and updates the remaining period RT and remaining data amount RV of the uncompleted transmission task to be processed in S43. Note that this maximum bandwidth SBW is also one of the available bandwidths. Here, the processing of S45 includes the case where the settable maximum bandwidth SBW is 0. In this case, a path for the uncompleted transmission task to be processed is not set in the allocation period n. In other words, for uncompleted transmission tasks, no path is set during the allocation period n, and therefore some result data may not be transmitted. After processing in S43, the determination device 2 determines in S44 whether there are any unprocessed uncompleted transmission tasks, and repeats the processing from S40 until there are no unprocessed uncompleted transmission tasks.

As described above, in this embodiment, in the process of each processing period, the remaining period RT of the transmission task is managed, and the necessary bandwidth RBW required to complete the transmission task by the deadline is determined based on the remaining period RT. The higher the necessary bandwidth RBW, the higher the priority of the bandwidth allocation. This configuration can suppress the occurrence of waiting time due to delays in the transmission task and suppress the increase in the processing time of the specified process. In addition, for a transmission task that is not completed even when the remaining period RT becomes 0 (a transmission task that exceeds the deadline), the processing period RT is extended to T and a bandwidth is allocated. If the period T is shorter than the initial value of the remaining period RT that can normally occur (the value of RT when the transmission task occurs), the necessary bandwidth RBW of the transmission task that exceeds the deadline becomes higher. In other words, the priority of the transmission task that exceeds the deadline becomes higher, and a bandwidth can be allocated to the transmission task that exceeds the deadline with priority. In this embodiment, the remaining period RT of the transmission task that exceeds the deadline is set to T, which is equal to the allocation period, in S22 of FIG. 4, but it is also possible to set the remaining period RT to a predetermined period that is shorter than the allocation period and greater than 0.

Furthermore, in this embodiment, the larger the required bandwidth RBW, the higher the priority, but it is also possible to configure it so that the shorter the remaining period RT, the higher the priority. In this case, when there are multiple uncompleted transmission tasks with the same remaining period RT, the priorities of these multiple uncompleted transmission tasks with the same remaining period RT can be determined by any method. As an example, when there are multiple uncompleted transmission tasks with the same remaining period RT, it is possible to configure it so that the larger the remaining data volume RV, the higher the priority.

For example, if network 4 is a combination of an optical network and an electrical network, the setting bandwidth of the path to be set in the optical network is first determined, and if a path with a bandwidth equal to or greater than the required bandwidth RBW cannot be set in the optical network, the setting bandwidth of the path to be set in the electrical network is determined.

Figure 7 is a block diagram of the determination device 2. The uncompleted transmission task determination unit 20 executes an uncompleted transmission task determination process. Specifically, based on the task information of the uncompleted transmission task output from the determination unit 22 by processing in the processing period n-1 and the occurrence information and completion information received from the scheduling device 1 in the collection period n, the uncompleted transmission task determination unit 20 determines the uncompleted transmission task in the processing period n, and outputs the task information of the uncompleted transmission task in the processing period n to the required bandwidth determination unit 21. The task information output by the uncompleted transmission task determination unit 20 to the required bandwidth determination unit 21 includes information indicating the source, destination, remaining data amount RV, and remaining period RT. As described above, if there is an uncompleted transmission task with RT≦0 among the determined uncompleted transmission tasks, the uncompleted transmission task determination unit 20 updates the RT of the uncompleted transmission task to a predetermined value greater than 0.

The necessary bandwidth determination unit 21 executes a necessary bandwidth determination process to determine the necessary bandwidth RBW and priority, and outputs task information of uncompleted transmission tasks in the processing period n to the determination unit 22. The task information that the necessary bandwidth determination unit 21 outputs to the determination unit 22 includes information indicating the source, destination, remaining data volume RV, remaining period RT, necessary bandwidth RBW, and priority.

The determination unit 22 executes a determination process to determine the set bandwidth SBW, and transmits setting information including information indicating the source, destination, and set bandwidth SBW for each uncompleted transmission task in the processing period n to the network control device 3. Note that there is no need to transmit setting information to the network control device 3 for transmission tasks for which the set bandwidth SBW is 0, that is, for transmission tasks for which no path is set. The determination unit 22 also updates the remaining data volume RV and remaining period RT for each uncompleted transmission task in the processing period n, and outputs the updated task information to the uncompleted transmission task determination unit 20.

The determination device 2 according to the present invention can be realized by a program that, when executed by one or more processors of a device or computer having one or more processors, causes the device or computer to operate and function as the determination device 2. These computer programs can be stored in a computer-readable storage medium or distributed via a network.

The above configuration can reduce the processing time when a given process is distributed across multiple computers. This makes it possible to contribute to Goal 9 of the United Nations' Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote sustainable industrialization and foster innovation."

20: Uncompleted transmission task determination unit, 21: Required bandwidth determination unit, 22: Determination unit

Claims (13)

In a system in which a predetermined process is divided into a plurality of jobs and each of the plurality of jobs is assigned to each of a plurality of computers connected to a network, a source computer which has executed an assigned job among the plurality of computers sets a set bandwidth of a path from the source computer to a destination computer which uses result data, the set bandwidth being set on the network, the source computer setting a set bandwidth of a path from the source computer to the destination computer, the set bandwidth comprising:
a first determination means for determining first task information of an incomplete first transmission task, the first task information indicating a remaining data amount RV of result data, a remaining time RT until the transmission of the result data is completed, and a source computer and a destination computer of the result data;
a second determination means for determining a required bandwidth RBW for each of the first transmission tasks based on the remaining data amount RV and the remaining time RT;
a determination means for determining a set bandwidth SBW to be allocated to each of the first transmission tasks during an allocation period of a period T, and performing a determination process for updating the remaining data amount RV and the remaining period RT of each of the first transmission tasks;
Equipped with
the determination means, in the determination process for a first allocation period, selects a second transmission task to be processed from the first transmission task in descending order of priority, determines whether a path with a bandwidth ABW equal to or greater than the required bandwidth RBW of the second transmission task from the source computer of the second transmission task to the destination computer can be set in the network, and if the bandwidth ABW can be set, determines the set bandwidth SBW of the second transmission task to be the set bandwidth SBW of the second transmission task, and if the bandwidth ABW can not be set, determines the maximum bandwidth that can be set in the network to be the set bandwidth SBW of the second transmission task. The determination device according to claim 1, wherein the determination means notifies the network control device of the source computer, the destination computer, and the determined set bandwidth SBW for each of the first transmission tasks. The determination device according to claim 1 or 2, wherein the maximum bandwidth that can be set for the network includes 0. The determination device according to any one of claims 1 to 3, wherein the determination means updates the remaining data amount RV by subtracting the product of the set bandwidth SBW and the period T from the remaining data amount RV, and updates the remaining period RT by subtracting the period T from the remaining period RT. The determination device according to any one of claims 1 to 4, wherein the bandwidth ABW is equal to or greater than the required bandwidth RBW and is the smallest bandwidth among one or more bandwidths available in the network. The determination device according to any one of claims 1 to 5, wherein the priority of the first transmission task is higher as the required bandwidth RBW is larger. The determination device according to any one of claims 1 to 5, wherein the priority of the first transmission task is higher as the remaining period RT is smaller. The determination device according to any one of claims 1 to 7, wherein the second determination means determines the required bandwidth RBW by dividing the remaining data volume RV by the remaining time period RT. the first determination means determines the first transmission task based on occurrence information indicating a newly generated third transmission task and completion information indicating a fourth transmission task for which transmission of the result data has been completed, the occurrence information being received during a collection period from a management device that manages schedules of the plurality of jobs;
When the first determination means determines the first transmission tasks, the second determination means determines the required bandwidth RBW for each of the first transmission tasks;
9. The device according to claim 1, wherein the determination means determines the set bandwidth SBW to be allocated to each of the first transmission tasks in the first allocation period that starts temporally later than the collection period when the second determination means determines the required bandwidth RBW for each of the first transmission tasks. The determination device according to claim 9, wherein the first determination means determines, as the first transmission task, a sixth transmission task obtained by excluding the fourth transmission task indicated by the completion information from a fifth transmission task for which the determination means determined the set bandwidth SBW in the determination process for a second allocation period immediately preceding the first allocation period, and the third transmission task indicated by the occurrence information. The determination device according to claim 10, wherein the first determination means updates the remaining period RT of the sixth transmission task to a value greater than 0 if the remaining period RT of the sixth transmission task is equal to or less than 0. The determination device according to claim 10, wherein the first determination means updates the remaining period RT of the sixth transmission task to the period T if the remaining period RT of the sixth transmission task is equal to or less than 0. A program that causes a computer to function as the determination device according to any one of claims 1 to 12.

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