WO2015037274A1

WO2015037274A1 - Load reduction device, server device and load reduction method

Info

Publication number: WO2015037274A1
Application number: PCT/JP2014/063043
Authority: WO
Inventors: 秀一稲葉
Original assignee: 株式会社東芝
Priority date: 2013-09-10
Filing date: 2014-05-16
Publication date: 2015-03-19
Also published as: JP2015055933A

Abstract

In the present invention, a load reduction device is provided with a storage device interface unit, a buffer memory unit, a data control unit, a packet generation unit, a communication interface unit, and a data release unit. The storage device interface unit acquires data from a storage device without using a processor. The buffer memory unit stores data. The data control unit causes the buffer memory unit to store data in regions. The packet generation unit generates, for each region, a packet that includes data read out from the buffer memory unit. The communication interface unit sends the packets to a client device. The data release unit releases data from the regions where data, which had been included in the packets received by an external device, has been read out.

Description

Load reduction device, server device, and load reduction method

Embodiments described herein relate generally to a load reduction device, a server device, and a load reduction method.

The server device generates a packet from the data stored in the storage device, and transmits the generated packet from the communication unit to the client device via the communication line. Here, in the server device, the data stored in the storage device is transferred to the communication unit via the bus under the control of the processor, so that the load on the processor is large. Therefore, there is a load reducing device for the purpose of reducing (offloading) the load on the processor.

JP 2005-192216 A Japanese Patent Laid-Open No. 2001-230812 JP 2010-136414 A JP 2010-148090 A

In order to reduce the load on the processor, even when data is directly transferred from the control unit of the storage device to the communication unit without going through the processor, the signal is connected via the bus in the server device. For this reason, in a system with a low transfer rate from the control unit of the storage device to the communication unit, there is a problem that a large amount of data cannot be distributed to the client device at high speed.

The problem to be solved by the present invention is that when data is directly transferred from a storage device to a communication unit without using a processor, a large amount of data can be transferred at high speed even in a system with a low transfer rate from the control unit of the storage device to the communication unit The present invention provides a load reducing device, a server device, and a load reducing method that can be distributed to client devices.

The load reduction device according to the embodiment includes a storage device interface unit, a buffer memory unit, a data control unit, a packet generation unit, a communication interface unit, and a data release unit. The storage device interface unit acquires data from the storage device without using a processor. The buffer memory unit can store data acquired from the storage device. The data control unit writes and stores the data acquired from the storage device in the buffer memory unit for each area defined in the buffer memory unit. The packet generation unit reads data for each area from the buffer memory unit, and generates a packet including the data read from the buffer memory unit for each area. The communication interface unit transmits the generated packet to the client device. The data release unit determines whether or not the packet is received by the client device, and obtains from the storage device from the area from which data included in the packet received by the client device is read Release the recorded data.

The server device of the embodiment includes a storage device and the load reduction device of the embodiment. The storage device stores data. The load reducing device includes a storage device interface unit, a buffer memory unit, a data control unit, a packet generation unit, a communication interface unit, and a data release unit. The storage device interface unit acquires data from the storage device without using a processor. The buffer memory unit can store data acquired from the storage device. The data control unit writes and stores the data acquired from the storage device in the buffer memory unit for each area defined in the buffer memory unit. The packet generation unit reads data for each area from the buffer memory unit, and generates a packet including the data read from the buffer memory unit for each area. The communication interface unit transmits the generated packet to the client device. The data release unit determines whether or not a packet is received by the client device, and is acquired from the storage device from the area from which data included in the packet received by the client device is read Free the data.

It is a block diagram which shows the structural example of the server apparatus in embodiment. It is a block diagram which shows the structural example of the load reduction apparatus in embodiment. It is a flowchart which shows the operation | movement procedure until it writes a packet in a communication memory part in embodiment. It is a flowchart which shows the operation | movement procedure until it transmits a packet from a communication interface part in embodiment. It is a flowchart which shows the operation | movement procedure which determines whether the packet is retransmitted in embodiment. It is a table | surface which divides | segments and shows the operation example of the load reduction apparatus in embodiment. It is a table | surface which divides | segments and shows the operation example of the load reduction apparatus in embodiment. It is a table | surface which divides | segments and shows the operation example of the load reduction apparatus in embodiment. It is a table | surface which divides | segments and shows the operation example of the load reduction apparatus in embodiment. It is a table | surface which divides | segments and shows the operation example of the load reduction apparatus in embodiment. It is a table | surface which divides | segments and shows the operation example of the load reduction apparatus in embodiment. It is a table | surface which divides | segments and shows the operation example of the load reduction apparatus in embodiment.

Embodiments will be described in detail with reference to the drawings. The load reducing device, the server device, and the load reducing method according to the embodiment have a large amount of data even in a system with a low transfer rate from the storage device to the communication unit when the data is directly transferred from the storage device to the communication unit without using a processor. Can be delivered at high speed.

First, a configuration example of the server device will be described.
FIG. 1 is a block diagram illustrating a configuration example of a server device. The server device 10 generates a packet including data, and transmits (distributes) the generated packet to the client device 30 via the communication line 20 (network). Examples of data included in the packet include image data (moving image data and still image data), audio data, and text data.

The server device 10 includes a bus 101, a processor 102, a storage unit 103, a storage device 106, and a load reduction device 110. A processor 102 (Central Processing Unit (CPU)) controls each unit of the server device 10 via the bus 101 based on a program stored in the storage unit 103.

The storage unit 103 stores various data. The various data may be parameter data generated when the processor 102 operates, for example. The storage unit 103 may store a program for operating the processor 102. The storage unit 103 may be a semiconductor memory. The storage unit 103 may be a temporary storage medium or a non-temporary storage medium.

The storage device 106 stores data included in a packet transmitted to the client device 30 in units of files. These files are identified based on information for identifying the file (data) (hereinafter referred to as “file identification information”). The storage device 106 may have a non-transitory storage medium such as a hard disk drive, for example. The storage device 106 may store data based on RAID (Redundant Array of Inexpensive Disks).

The load reduction device 110 (hardware) acquires data from the storage device 106 without going through the processor 102. For example, the load reducing device 110 may acquire data from the storage device 106 by DMA (Direct Memory Memory Access). The load reduction device 110 includes a storage device control unit 105, a communication unit 104, and a connection unit 107. Data may also be transferred between these units of the load reducing device 110 by DMA.

Next, a configuration example of the load reducing device 110 will be described.
FIG. 2 is a block diagram illustrating a configuration example of the load reducing device. More specifically, the load reduction device 110 includes a bus interface unit 111, a storage device control unit 105, a communication unit 104, and a connection unit 107.

The storage device control unit 105 includes a storage device interface unit 115 and a data control unit 114. The data control unit 114 includes a write area counter C202.
The connection unit 107 includes a buffer memory unit 116, a control communication line S301, a write communication line S302, and a read communication line S303. The control communication line S301 is a communication line between the communication unit 104 and the storage device control unit 105. The write communication line S302 is a communication line between the buffer memory unit 116 and the storage device control unit 105. The read communication line S303 is a communication line between the buffer memory unit 116 and the communication unit 104.

The communication unit 104 includes a control unit 112, a communication interface unit 113, and a communication memory unit 118. The control unit 112 (TOE: TCP / IP Offload Engine) includes a packet generation unit 1121, a data release unit 1122, an index memory unit 117, an ACK reception area counter C201, and a read area counter C203. The control unit 112 may further include a write area counter C202 instead of the data control unit 114 including the write area counter C202.

Various information is input to the bus interface unit 111 via the bus 101 (see FIG. 1). The various types of information may include, for example, file identification information. The file identification information is input from the processor 102 via the bus 101. The bus interface unit 111 transfers the file identification information to the storage device control unit 105 and the communication unit 104.

The bus interface unit 111 may receive operation state information from at least one of the storage device control unit 105 and the communication unit 104. This operation state information may be information indicating the operation state of at least one of the storage device control unit 105 and the communication unit 104, for example.
The bus interface unit 111 may transfer operation state information input from at least one of the storage device control unit 105 and the communication unit 104 to the processor 102 via the bus 101.

In the buffer memory unit 116, an area is determined according to the size (length) of the packet generated by the communication unit 104. Hereinafter, as an example, the buffer memory unit 116 will be described on the assumption that the areas 1 to 6 are defined. The buffer memory unit 116 can store data written in each area from the data control unit 114 via the write communication line S302. The buffer memory unit 116 may be a semiconductor memory.

The write area counter C202 is a counter indicating an area in which data acquired by the data control unit 114 from the storage device interface unit 115 is written. In FIG. 2, the write area counter C 202 is a counter indicating an index number indicating one of the areas 1 to 6.
File identification information is input to the data control unit 114 from the packet generation unit 1121 via the control communication line S301. The data control unit 114 transfers the file identification information to the storage device interface unit 115. As a response to this transfer, data acquired from the storage device 106 by the storage device interface unit 115 based on the file identification information is input from the storage device interface unit 115 to the data control unit 114.

Note that file identification information may be input from the bus interface unit 111 to the data control unit 114. Further, the data control unit 114 may control the storage device interface unit 115 based on RAID.

The data control unit 114 updates the write area counter C202, and enters the area defined in the buffer memory unit 116 indicated by the updated write area counter C202 from the storage device interface unit 115 via the write communication line S302. Write and store the acquired data.

The file identification information is input from the data control unit 114 to the storage device interface unit 115. The storage device interface unit 115 accesses the storage device 106 and refers to the file identified by the file identification information. The storage device interface unit 115 acquires data from the referenced file within the packet size. The storage device interface unit 115 transfers the acquired data to the data control unit 114.

Note that the storage device interface unit 115 may access the storage device 106 and acquire data based on the SATA (Serial Advanced Technology Attachment) standard or the SCSI (Small Computer System Interface) standard.

The communication interface unit 113 performs communication with the client device 30 (see FIG. 1) via the communication line 20 (see FIG. 1). The communication interface unit 113 may be identified on the communication line 20 based on the MAC address (Media Access Control address). The value of the read area counter C203 is input from the packet generation unit 1121 to the communication interface unit 113. The communication interface unit 113 acquires a packet from the communication memory unit 118 based on the value of the read area counter C203, and transmits the acquired packet to the client device 30.

The communication interface unit 113 receives an ACK signal from the client device 30. This ACK signal (acknowledgment) is a signal transmitted to the server apparatus 10 as a response from the client apparatus 30 that has received the packet transmitted from the server apparatus 10 (transmitted packet). The ACK signal is associated with the packet transmitted from the communication interface unit 113 to the client device 30. For example, the ACK signal may include information (packet identification information) for identifying a packet transmitted from the server device 10.
The communication interface unit 113 stores the received ACK signal in the communication memory unit 118. The communication interface unit 113 may store a signal other than the ACK signal received from the client device 30 in the communication memory unit 118.

The communication memory unit 118 is a buffer provided to absorb that there is a difference in operation timing and speed between the control unit 112 and the communication interface unit 113. The communication memory unit 118 stores the packet generated by the packet generation unit 1121 and the value of the write area counter C202 input from the packet generation unit 1121 in association with each other. Further, the communication memory unit 118 stores a signal (for example, an ACK signal) received by the communication interface unit 113.

The index memory unit 117 stores an index indicating an area defined in the buffer memory unit 116. The index items include the start address of the area, the area size (area length), and the “index number of the next area”. The area size is determined according to the packet size. Examples of indexes will be described later with reference to FIGS.

Note that the next consecutive index number is not necessarily assigned to the index item “next area index number”. This is because when the server apparatus 10 executes a plurality of communication connections (connections) in parallel, the index number may be used by another communication connection. In the following description, the index item “next area index number” is assumed to be assigned the next consecutive index number.

The value of the write area counter C202 is input to the packet generator 1121 from the data controller 114 via the control communication line S301. The packet generator 1121 reads data from the area defined in the buffer memory unit 116 indicated by the write area counter C202. The packet generation unit 1121 generates a packet including the read data. The packet generation unit 1121 associates the generated packet with the value of the write area counter C202 and stores it in the communication memory unit 118. Therefore, the generated packet includes data read from the area defined in the buffer memory unit 116 indicated by the associated write area counter C202.

When the packet generation unit 1121 transmits a packet from the communication interface unit 113, the packet generation unit 1121 indicates an index (next area) stored in the index memory unit 117 to indicate an area from which data included in the packet to be transmitted is read. The read area counter C203 is updated based on the index number). The packet generation unit 1121 outputs the value of the read area counter C203 to the communication interface unit 113.

When the time at which the communication interface unit 113 receives the ACK signal from the client device 30 has timed out, the packet generation unit 1121 reads the data contained in the transmitted packet associated with the timed-out ACK signal. The read area counter C203 is returned until the designated area is indicated.

When the communication interface unit 113 receives the ACK signal from the client device 30, the data release unit 1122 indicates an area where data included in the transmitted packet associated with the received ACK signal is read. The ACK reception area counter C201 is updated.

The data release unit 1122 releases data from each area of the buffer memory unit 116 indicated by the ACK reception area counter C201. Here, the data release unit 1122 releases the data by invalidating the index indicating each area of the buffer memory unit 116 indicated by the ACK reception area counter C201. For example, the data release unit 1122 registers “invalidity (for example, value 0)” in the index item “index number of the next region” indicating each region of the buffer memory unit 116 indicated by the ACK reception region counter C201. , Release the data.

The read area counter C203 is a counter indicating an area in which data included in a transmitted packet is stored. In FIG. 2, the counter indicates an index number indicating one of the areas 1 to 6.
The ACK reception area counter C201 is a counter indicating an area in which data included in the packet identified by the received ACK signal is stored. In FIG. 2, the counter indicates an index number indicating one of the areas 1 to 6.

Next, an operation procedure example will be described.
FIG. 3 is a flowchart showing an operation procedure until a packet is written in the communication memory unit.

(Step S1) The data control unit 114 and the control unit 112 obtain file identification information via the bus interface unit 111. The control unit 112 outputs the file identification information to the data control unit 114 via the control communication line S301. The data control unit 114 transfers the file identification information to the storage device interface unit 115. The storage device interface unit 115 refers to the file stored in the storage device 106 based on the file identification information.

(Step S2) The storage device interface unit 115 acquires data from the referenced file within the packet size. The storage device interface unit 115 transfers the acquired data to the data control unit 114. The storage device interface unit 115 may acquire data with a size larger than the packet size from the referenced file, discard excess data, and transfer the remaining data without discarding.

(Step S3) The data control unit 114 updates the write area counter C202, and writes and stores the acquired data in an area defined in the buffer memory unit 116 indicated by the updated write area counter C202.

(Step S4) The packet generation unit 1121 reads data from an area defined in the buffer memory unit 116 indicated by the write area counter C202.
(Step S5) The packet generation unit 1121 generates a packet including the read data.
(Step S6) The packet generation unit 1121 stores the generated packet in the communication memory unit 118.

(Step S6) The packet generation unit 1121 determines whether data has been read up to the end of the file identified by the file identification information. When the data is read to the end of the file (step S6: Yes), the packet generator 1121 ends the process.
On the other hand, when data has not been read up to the end of the file (step S6: No), the packet generator 1121 returns the process to step S3.

FIG. 4 is a flowchart showing an operation procedure until a packet is transmitted from the communication interface unit.
(Step Sa1) When the packet generation unit 1121 transmits a packet from the communication interface unit 113, the packet generation unit 1121 updates the read region counter C203 to indicate the region from which the data included in the packet to be transmitted is read. The packet generation unit 1121 outputs the value of the read area counter C203 to the communication interface unit 113.

(Step Sa2) The communication interface unit 113 reads, from the communication memory unit 118, a packet including data read from the area defined in the buffer memory unit 116 indicated by the read area counter C203.

(Step Sa3) The communication interface unit 113 determines whether or not the packet read from the communication memory unit 118 can be transmitted based on a predetermined condition (for example, TCP / IP protocol). When the packet read from the communication memory unit 118 can be transmitted (step Sa3: Yes), the communication interface unit 113 advances the process to step Sa3. On the other hand, when the packet read from the communication memory unit 118 cannot be transmitted (step Sa3: No), the communication interface unit 113 re-executes step Sa3.
(Step Sa4) The communication interface unit 113 transmits the packet read from the communication memory unit 118 to the client device 30 via the communication line 20, and ends the process.

FIG. 5 is a flowchart showing an operation procedure for determining whether or not to retransmit a packet. In the example of the operation procedure, the communication interface unit 113 receives an ACK signal for each packet. However, the communication interface unit 113 may receive an ACK signal for each of a plurality of packets.
(Step Sb1) The packet generation unit 1121 determines whether or not the communication interface unit 113 has received an ACK signal from the client device 30. When the communication interface unit 113 receives the ACK signal from the client device 30 (step Sb1: Yes), the packet generation unit 1121 advances the process to step Sb4. On the other hand, when the communication interface unit 113 has not received the ACK signal from the client device 30 (step Sb1: No), the packet generation unit 1121 advances the processing to step Sb2.

(Step Sb2) The packet generation unit 1121 determines whether or not the time when the communication interface unit 113 receives the ACK signal from the client device 30 has timed out. When the time when the communication interface unit 113 receives the ACK signal from the client device 30 has passed and timed out (step Sb2: Yes), the packet generation unit 1121 advances the process to step Sb3. On the other hand, when the time when the communication interface unit 113 receives the ACK signal from the client device 30 has not passed and the timeout has not occurred (step Sb2: No), the packet generation unit 1121 returns the process to step Sb1.

(Step Sb3) The packet generation unit 1121 returns the read area counter C203 until it indicates the area from which data included in the transmitted packet associated with the timed-out ACK signal is read. The packet generator 1121 ends the process.

(Step Sb4) The data release unit 1122 updates the ACK reception area counter C201 until it indicates an area from which data included in the transmitted packet associated with the received ACK signal is read.

(Step Sb5) The data release unit 1122 releases data from each area of the buffer memory unit 116 indicated by the ACK reception area counter C201. Here, the data release unit 1122 releases the data by invalidating the index indicating each area of the buffer memory unit 116 indicated by the ACK reception area counter C201.

Next, an operation example of the load reducing device 110 will be described.
In FIG. 6, FIG. 7, FIG. 8, FIG. 9, FIG. 10, FIG. 11 and FIG. That is, FIGS. 6 to 12 show operations that are performed in the order of these drawings. In the tables shown in FIGS. 6 to 12, the order of operation is the order from the top to the bottom. 6 to 12 will be described only with respect to differences (differences) from the most recent operation.

<Operation “Initialization at Connection” shown in FIG. 6>
The packet generator 1121 initializes the index stored in the index memory unit 117. Here, the packet generation unit 1121 may initialize only a part of the index. In FIG. 6, the packet generation unit 1121 sets the index of the area indicated by the index number 1 as the initial value of (area start address, area size, index number of next area) = (invalid, invalid, invalid). Turn into. Therefore, the indexes of the areas indicated by the index numbers 2 to 6 are not initialized and are “undefined”.

The value of the write area counter C202 is index number 0 (invalid). The value of the read area counter C203 is index number 0 (invalid). The value of the ACK reception area counter C201 is index number 0 (invalid).
None of the areas 1 to 6 defined in the buffer memory unit 116 stores data, and the data is undefined.

<Operation “Generate First Packet” shown in FIG. 6>
The data control unit 114 stores data to be included in the first packet in the area 1 defined in the buffer memory unit 116. The data control unit 114 updates the value of the write area counter C202 (index number 0) to index number 1.
The packet generator 1121 updates the index of the area indicated by the index number 1 as (area start address, area size, index number of next area) = (area 1 start, area 1 size, end). Here, the term “end” indicates an area in which the last data transmitted as a packet is stored. The packet generator 1121 acquires data from the area 1 indicated by the value (index number 1) of the write area counter C202, and generates a first packet.
In this operation example, data to be included in the packet is written in the buffer memory unit 116, but the generated packet or a part thereof may be written.

<Operation “Send first packet” shown in FIG. 6>
The packet generator 1121 updates the value (index number 0) of the read area counter C203 to the index number 1.
The communication interface unit 113 transmits, from the communication memory unit 118, the first packet stored in association with the value (index number 1) of the write area counter C202 that is the same as the value of the read area counter C203 (index number 1). The acquired first packet is transmitted to the client device 30.

<Operation “Receiving ACK Signal Associated with First Packet” shown in FIG. 6>
It is assumed that the communication interface unit 113 receives an ACK signal associated with the first packet.
The data release unit 1122 updates the ACK reception area counter C201 up to the index number 1 indicating the area 1 from which the data included in the transmitted first packet associated with the received ACK signal is read.
The data release unit 1122 updates the index of the area indicated by the index number 1 as (area start address, area size, index number of next area) = (area 1 start, area 1 size, invalid). As a result, the data stored in the area 1 defined in the buffer memory unit 116 is released.

<Operation “Generate second packet” shown in FIG. 7>
The data control unit 114 stores data to be included in the second packet in the area 2 defined in the buffer memory unit 116. The data control unit 114 updates the value of the write area counter C202 (index number 1) to index number 2.
The packet generator 1121 updates the index of the area indicated by the index number 2 as (area start address, area size, index number of next area) = (area 2 start, area 2 size, end). The packet generator 1121 acquires data from the area 2 indicated by the value (index number 2) of the write area counter C202, and generates a second packet.

<Operation “Generate third packet” shown in FIG. 7>
The data control unit 114 stores data to be included in the third packet in the area 3 defined in the buffer memory unit 116. The data control unit 114 updates the value (index number 2) of the write area counter C202 to the index number 3.
The packet generation unit 1121 updates the index of the area indicated by the index number 2 as (area start address, area size, next area index number) = (area 2 start, area 2 size, index number 3). . Thereby, the data included in the area 3 indicated by the index number 3 follows the data included in the area 2 indicated by the index number 2.
The packet generation unit 1121 updates the index of the area indicated by the index number 3 as (area start address, area size, next area index number) = (area 3 start, area 3 size, end). The packet generator 1121 acquires data from the area 3 indicated by the value (index number 3) of the write area counter C203, and generates a third packet.

<Operation “Generate Fourth Packet” shown in FIG. 7>
The data control unit 114 stores data to be included in the fourth packet in the area 4 defined in the buffer memory unit 116. The data control unit 114 updates the value (index number 3) of the write area counter C202 to the index number 4.
The packet generator 1121 updates the index of the area indicated by the index number 3 as (area start address, area size, index number of next area) = (area 3 start, area 3 size, index number 4). . Thereby, the data included in the area 4 indicated by the index number 4 follows the data included in the area 3 indicated by the index number 3.
The packet generation unit 1121 updates the index of the area indicated by the index number 4 as (area start address, area size, index number of next area) = (area 4 start, area 4 size, end). The packet generator 1121 acquires data from the area 4 indicated by the value (index number 4) of the write area counter C203, and generates a fourth packet.
In this operation example, the data control unit 114 stores the data to be included in the second to fourth packets in the buffer memory unit 116 for each packet (divided into three times). When a plurality of packets are generated due to a large amount, index processing may be executed continuously and data reading may be executed continuously.

<Operation “Send second packet” shown in FIG. 8>
The packet generator 1121 updates the value (index number 1) of the read area counter C203 to the index number 2.
The communication interface unit 113 sends the second packet stored in association with the value (index number 2) of the write area counter C202 that is the same as the value of the read area counter C203 (index number 2) from the communication memory unit 118. The acquired second packet is transmitted to the client device 30.

<Operation “Send third packet” shown in FIG. 8>
The packet generator 1121 updates the value (index number 2) of the read area counter C203 to the index number 3.
The communication interface unit 113 transmits the third packet stored in association with the value (index number 3) of the write area counter C202 that is the same as the value of the read area counter C203 (index number 3) from the communication memory unit 118. The acquired third packet is transmitted to the client device 30.

<Operation “Send 4th Packet” shown in FIG. 8>
The packet generator 1121 updates the value (index number 3) of the read area counter C203 to the index number 4.
The communication interface unit 113 transmits the fourth packet stored in association with the value (index number 4) of the write area counter C202 that is the same as the value of the read area counter C203 (index number 4) from the communication memory unit 118. The acquired fourth packet is transmitted to the client device 30.

<Operation “Receiving ACK Signal Associated with Third Packet” shown in FIG. 8>
It is assumed that the communication interface unit 113 receives an ACK signal associated with the third packet.
The data release unit 1122 updates the ACK reception area counter C201 up to the index number 3 indicating the area 3 from which the data included in the transmitted third packet associated with the received ACK signal is read.

The data release unit 1122 sets the index of the area indicated by the index number 2 before the index number 3 as (area start address, area size, next area index number) = (area 2 start, area 2 size, invalid ) And update. As a result, the data stored in the area 2 defined in the buffer memory unit 116 is released. Further, the data release unit 1122 updates the index of the area indicated by the index number 3 as (area start address, area size, next area index number) = (area 3 start, area 3 size, invalid). . As a result, the data stored in the area 3 defined in the buffer memory unit 116 is released.

<Operation “Generate fifth packet” shown in FIG. 9>
The data control unit 114 stores the data included in the fifth packet in the area 5 defined in the buffer memory unit 116. The data control unit 114 updates the value (index number 4) of the write area counter C202 to the index number 5.
The packet generation unit 1121 updates the index of the area indicated by the index number 4 as (area start address, area size, next area index number) = (area 4 start, area 4 size, index number 5). . Thereby, the data included in the area 5 indicated by the index number 5 follows the data included in the area 4 indicated by the index number 4.
The packet generation unit 1121 updates the index of the area indicated by the index number 5 as (area start address, area size, next area index number) = (area 5 start, area 5 size, end). The packet generator 1121 acquires data from the area 5 indicated by the value (index number 5) of the write area counter C203, and generates a fifth packet.

<Operation “Send fifth packet” shown in FIG. 9>
The packet generator 1121 updates the value (index number 4) of the read area counter C203 to the index number 5.
The communication interface unit 113 transmits, from the communication memory unit 118, the fifth packet stored in association with the value (index number 5) of the write area counter C202 that is the same as the value of the read area counter C203 (index number 5). The acquired fifth packet is transmitted to the client device 30.

<Operation “Receiving ACK Signal Associated with Fifth Packet” shown in FIG. 9>
It is assumed that the communication interface unit 113 receives an ACK signal associated with the fifth packet.
The data release unit 1122 updates the ACK reception area counter C201 up to an index number 5 indicating the area 5 from which data included in the transmitted fifth packet associated with the received ACK signal is read.

The data release unit 1122 updates the index of the area indicated by the index number 5 as (area start address, area size, next area index number) = (area 5 start, area 5 size, invalid). As a result, the data stored in the area 5 defined in the buffer memory unit 116 is released.

<Operation “Generate Sixth Packet” shown in FIG. 10>
The data control unit 114 stores the data included in the sixth packet in the area 6 defined in the buffer memory unit 116. The data control unit 114 updates the value of the write area counter C202 (index number 5) to the index number 6.
The packet generator 1121 updates the index of the area indicated by the index number 5 as (area start address, area size, index number of next area) = (area 5 start, area 5 size, index number 6). . As a result, the data included in the area 6 indicated by the index number 6 follows the data included in the area 5 indicated by the index number 5.
The packet generation unit 1121 updates the index of the area indicated by the index number 6 as (area start address, area size, index number of next area) = (start of area 6, area 6 size, end). The packet generator 1121 acquires data from the area 6 indicated by the value (index number 6) of the write area counter C203, and generates a sixth packet.

<Operation “Generate Seventh Packet” shown in FIG. 10>
The data control unit 114 stores the data included in the seventh packet in the area 1 defined in the buffer memory unit 116. The data control unit 114 updates the value (index number 6) of the write area counter C202 to index number 1.
The packet generator 1121 updates the index of the area indicated by the index number 1 as (area start address, area size, index number of next area) = (area 1 start, area 1 size, end). The packet generator 1121 acquires data from the area 1 indicated by the value (index number 1) of the write area counter C203, and generates a seventh packet.
The index is used repeatedly. Therefore, among the indexes updated when generating the seventh packet, the head of region 1 and the size of region 1 are not necessarily the same index values as when the first packet was generated.

<Operation “Send sixth packet” shown in FIG. 10>
The packet generator 1121 updates the value (index number 5) of the read area counter C203 to the index number 6.
The communication interface unit 113 transmits, from the communication memory unit 118, the sixth packet stored in association with the value (index number 6) of the write area counter C202 that is the same as the value of the read area counter C203 (index number 6). The acquired sixth packet is transmitted to the client device 30.

<Operation “Send Seventh Packet” shown in FIG. 10>
The packet generator 1121 updates the value (index number 6) of the read area counter C203 to index number 1.
The communication interface unit 113 transmits, from the communication memory unit 118, the seventh packet stored in association with the value (index number 1) of the writing area counter C202 that is the same as the value of the reading area counter C203 (index number 1). The acquired seventh packet is transmitted to the client device 30.

<Operation “Generate Eighth Packet” shown in FIG. 11>
The data control unit 114 stores the data included in the eighth packet in the area 2 defined in the buffer memory unit 116. The data control unit 114 updates the value of the write area counter C202 (index number 1) to index number 2.
The packet generator 1121 updates the index of the area indicated by the index number 2 as (area start address, area size, index number of next area) = (area 2 start, area 2 size, end). The packet generator 1121 acquires data from the area 2 indicated by the value (index number 2) of the write area counter C203, and generates an eighth packet.

<Operation “Timeout of Sixth Packet” shown in FIG. 11>
Assume that the time when the communication interface unit 113 receives the ACK signal associated with the sixth packet from the client device 30 has passed, and the ACK signal associated with the sixth packet has timed out.
The packet generator 1121 returns the read area counter C203 to the value of the ACK reception area counter indicating the area from which the data included in the packet normally received by the client device 30 has been read. More specifically, the packet generator 1121 reads up to the index number 5 indicating the area 5 from which the data included in the transmitted fifth packet associated with the ACK signal that has not timed out is read. Returns the area counter C203.

<Operation “Retransmission of Sixth Packet” shown in FIG. 11>
The packet generator 1121 updates the value (index number 5) of the read area counter C203 to the index number 6.
The communication interface unit 113 transmits, from the communication memory unit 118, the sixth packet stored in association with the value (index number 6) of the write area counter C202 that is the same as the value of the read area counter C203 (index number 6). The acquired sixth packet is retransmitted to the client device 30.

<Operation “Receiving ACK Signal Associated with Sixth Packet” shown in FIG. 11>
It is assumed that the communication interface unit 113 receives an ACK signal associated with the retransmitted sixth packet.
The data release unit 1122 updates the ACK reception area counter C201 up to the index number 6 indicating the area 6 from which the data included in the retransmitted sixth packet associated with the received ACK signal is read. .
The data release unit 1122 updates the index of the area indicated by the index number 6 as (area start address, area size, next area index number) = (area 6 start, area 6 size, invalid). Thereby, the data stored in the area 6 defined in the buffer memory unit 116 is released.

<Operation “Retransmission of seventh packet” shown in FIG. 12>
The packet generator 1121 updates the value (index number 6) of the read area counter C203 to index number 1.
The communication interface unit 113 transmits, from the communication memory unit 118, the seventh packet stored in association with the value (index number 1) of the writing area counter C202 that is the same as the value of the reading area counter C203 (index number 1). The acquired seventh packet is retransmitted to the client device 30.

<Operation “Send 8th Packet” shown in FIG. 12>
The packet generator 1121 updates the value (index number 1) of the read area counter C203 to the index number 2.
The communication interface unit 113 transmits, from the communication memory unit 118, the seventh packet stored in association with the value (index number 1) of the writing area counter C202 that is the same as the value of the reading area counter C203 (index number 1). The acquired seventh packet is transmitted to the client device 30.

<Operation “Receiving ACK Signal Associated with Seventh Packet” shown in FIG. 12>
It is assumed that the communication interface unit 113 receives an ACK signal associated with the retransmitted seventh packet.
The data release unit 1122 updates the ACK reception area counter C201 up to the index number 1 indicating the area 1 from which the data included in the retransmitted seventh packet associated with the received ACK signal is read. .
The data release unit 1122 updates the index of the area indicated by the index number 1 as (area start address, area size, index number of next area) = (area 1 start, area 1 size, invalid). As a result, the data stored in the area 1 defined in the buffer memory unit 116 is released.

<Operation “Receiving ACK Signal Associated with Eighth Packet” shown in FIG. 12>
It is assumed that the communication interface unit 113 receives an ACK signal associated with the transmitted eighth packet.
The data release unit 1122 updates the ACK reception area counter C201 up to the index number 2 indicating the area 2 from which the data included in the transmitted eighth packet associated with the received ACK signal is read.
The data release unit 1122 updates the index of the area indicated by the index number 2 as (area start address, area size, next area index number) = (area 2 start, area 2 size, invalid). As a result, the data stored in the area 2 defined in the buffer memory unit 116 is released.

<Operation "Disconnect" shown in FIG. 12>
The communication interface unit 113 disconnects (disconnects) communication with the client device 30. In the example shown in FIG. 12, there is no untransmitted data. If there is untransmitted data, the data release unit 1122 releases the untransmitted data by invalidating the index indicating each area of the buffer memory unit 116 indicated by the ACK reception area counter C201.

As described above, the load reduction device 110 includes the storage device interface unit 115, the buffer memory unit 116, the data control unit 114, the packet generation unit 1121, the communication interface unit 113, and the data release unit 1122. The storage device interface unit 115 acquires data from the storage device 106 without using the processor 102. The buffer memory unit 116 can store data acquired from the storage device 106. The data control unit 114 writes and stores the data acquired from the storage device 106 in the buffer memory unit 116 for each area defined in the buffer memory unit 116. The packet generation unit 1121 reads data from the buffer memory unit 116 for each region, and generates a packet including the data read from the buffer memory unit 116 for each region. The communication interface unit 113 transmits the generated packet to the client device 30. The data release unit 1122 determines whether or not the client device 30 has received a packet (whether or not the communication interface unit has received an ACK signal from the client device 30), and is included in the packet received by the client device 30. The data acquired from the storage device 106 is released (the index is invalidated) from the area where the data that has been read is read.
The server device 10 includes a storage device 106 and a load reduction device 110. The storage device 106 stores data.

The load reduction method is a load reduction method in the load reduction device 110, and includes a step executed by the storage device interface unit 115, a step executed by the data control unit 114, a step executed by the packet generation unit 1121, and a communication interface. And a step executed by the data release unit 1122. In the step executed by the storage device interface unit 115, the storage device interface unit 115 acquires data from the storage device 106 without using a processor. In the step executed by the data control unit 114, the data control unit 114 writes and stores the data acquired from the storage device 106 in the buffer memory unit 116 for each area defined in the buffer memory unit 116. In the step executed by the packet generation unit 1121, the packet generation unit 1121 reads data for each area from the buffer memory unit 116, and generates a packet including the data read from the buffer memory unit 116 for each area. In the step executed by the communication interface unit 113, the generated packet is transmitted to the client device 30. In the step executed by the data release unit 1122, the data release unit 1122 determines whether or not the client device 30 has received a packet (whether or not the communication interface unit has received an ACK signal from the client device 30), and the client The data acquired from the storage device 106 is released from the area from which the data included in the packet received by the device 30 is read (index is invalidated).

With this configuration, the storage device interface unit 115 acquires data from the storage device 106 without using the processor 102. The data control unit 114 writes and stores the data acquired from the storage device 106 in the buffer memory unit 116 for each area defined in the buffer memory unit 116. The data release unit 1122 determines whether or not a packet is received by the client device 30, and is acquired from the storage device 106 from an area from which data included in the packet received by the client device 30 is read. Free the data.

As a result, the load reducing device 110, the server device 10 and the load reducing method allow the data transfer from the storage device 106 to the communication unit when the data is directly transferred from the storage device to the communication unit without going through the processor (for example, performing DMA transfer). Even in a system with a low transfer rate to 104, a large amount of data can be distributed to the client device 30 at high speed.

That is, in the load reduction device 110, the server device 10, and the load reduction method, the storage area secured for each connection is only the area for storing the index, and the data included in the packet is the buffer memory unit 116 (common part). Is remembered. As a result, the load reducing device 110, the server device 10 and the load reducing method use memory efficiently, so that a large amount of data can be transferred to a client at high speed without using a large capacity memory (even in a system with a low transfer rate). It can be delivered to the device 30.

The data control unit 114 stores the data acquired from the storage device 106 in the buffer memory unit 116 for each region defined in the buffer memory unit 116, and indicates the region where the data acquired from the storage device 106 is stored. The writing area counter C202 may be updated. The packet generator 1121 may read data from the area indicated by the updated write area counter C202 and generate a packet including the read data.

The data release unit 1122 may update the read area counter C203 indicating the area from which the data included in the packet is read when the packet is transmitted from the communication interface unit 113. If the transmitted packet has not been received by the client device 30 (the communication interface unit has not received an ACK signal from the client device 30), the data release unit 1122 performs the transmission that has not been received by the client device 30. The read area counter C203 may be returned until it indicates the area from which the data contained in the completed packet has been read.

According to the load reducing device of at least one embodiment described above, when data is directly transferred from the storage device to the communication unit without using a processor, a large amount of data is transferred even in a system having a low transfer rate from the storage device to the communication unit. Data can be distributed at high speed.

Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

For example, at least a part of the server device of the embodiment may be configured by a cloud server device. That is, at least a part of the processing executed by the server device of the embodiment may be executed by cloud computing.

This cloud computing includes SaaS (Software as a Service) that provides an application (software) as a service, PaaS (Platform as a Service as a service) that provides a platform (platform) for running an application, At least one of IaaS (Infrastructure 演算 as AＳService) that provides resources such as a server device, a central processing unit, and a storage as a service (public cloud) may be included. For example, this cloud computing may include remote operation via the Internet by a cloud service providing layer (PaaS).

In the server device according to the embodiment, at least one of monitoring, failure handling, and operation may be performed by a proxy service. For example, an ASP (Application Service Provider) may act on behalf of the server device of the embodiment to monitor, troubleshoot and operate. In addition, the server device of the embodiment may be monitored, handled by a failure, and operated by a plurality of entities.

Claims

A storage device interface unit for acquiring data from the storage device without going through a processor;
A buffer memory unit capable of storing data acquired from the storage device;
A data control unit that writes and stores data acquired from the storage device in the buffer memory unit for each area defined in the buffer memory unit;
A packet generation unit that reads out data for each region from the buffer memory unit and generates a packet including the data read from the buffer memory unit for each region;
A communication interface unit for transmitting the generated packet to a client device;
Determine whether the client device has received the packet, and release the data acquired from the storage device from the area from which the data contained in the packet received by the client device has been read A data release unit to perform,
A load reducing device comprising:
The data control unit stores the data acquired from the storage device in the buffer memory unit for each region defined in the buffer memory unit, and stores the region in which the data acquired from the storage device is stored. Update the writing area counter shown
The load reducing device according to claim 1, wherein the packet generation unit reads data from the area indicated by the updated write area counter, and generates a packet including the read data.
The data release unit updates a read area counter indicating the area from which data included in a packet has been read when the packet is transmitted from the communication interface unit, and the transmitted packet is If not received by the client device, the read area counter is returned until it indicates the area from which data contained in the transmitted packet not received by the client apparatus is read. The load reducing device according to claim 1 or 2.
A storage device for storing data;
The load reducing device according to any one of claims 1 to 3,
A server device comprising:
A load reduction method in a load reduction device,
A storage device interface unit acquiring data from the storage device without going through a processor;
A step of writing and storing data acquired from the storage device in the buffer memory unit for each area defined in the buffer memory unit;
A packet generation unit that reads data for each area from the buffer memory unit, and generates a packet including the data read from the buffer memory unit for each area;
A communication interface unit transmitting the generated packet to a client device;
A data release unit determines whether or not the packet is received by the client device, and obtains from the storage device from the area from which data included in the packet received by the client device is read Releasing released data; and
A method of reducing the load.