CN101115008A - A reputation-based traffic control system, device and method - Google Patents

Abstract

The invention discloses a reputation-based flow control system, device and method. The system includes a multiport switch device. The switch device includes a plurality of port modules, an arbitration module and a routing module; the port module includes a sending module, a receiving module and a flow control module; the receiving module includes a plurality of virtual channel receiving buffer areas. The arbitration module also includes a record sub-module, which is used to record the FPL value of the arbitration failure according to the transmission request; the flow control module also includes a judgment sub-module, which is used for when the sending module of the receiving end has a data packet to send to the receiving module of the sending end, the flow control of the receiving end The module judges whether to send a flow control packet to the receiving module of the sending end by comparing the FPL value of arbitration failure sent by the sending module of the sending end with the remaining local reputation value of the current receiving end and the remaining resources of the current resource. It improves the efficiency of the flow control method of the data communication network, and improves the utilization rate of link and buffer area resources in the switching network.

Description

A reputation-based traffic control system, device and method

technical field

The invention relates to the field of data communication networks, in particular to a credit-based flow control system, device and method, which are suitable for flow control of end-to-end links in high-speed data communication networks.

Background technique

In a switch-based interconnection network, a switch device is connected to a processing node or a switch device in a point-to-point manner to form a network link for data communication. The switch device includes a plurality of communication ports, and each communication port includes three modules of sending, receiving and flow control, and the two ends of the communication ports of the plurality of switches are respectively connected to form a network link for data communication.

The sending module is used to send data packets and flow control packets.

The receiving module is used to extract data packets and flow control packets from the received data flow. A typical high-performance network switch uses a multi-queue structure to buffer data in its receiving module. Each queue corresponds to a virtual channel (Virtual Channel). The virtual channel includes a data buffer area, which is used to buffer its destination port that is temporarily unavailable. data packets.

In addition to each module in the port, the switch device also includes a routing module, an arbitration module and cross interconnections between them.

The routing module applies for the corresponding port for data transmission according to the destination port provided by the data packet; the arbitration module arbitrates the routing module that applies for the same destination port, and if the arbitration succeeds, it can transmit the data to its destination port; if it fails, continue to wait for the next time Arbitration results.

Flow control, also called flow control, is a mechanism for the receiving end to control the data transmission of the sending end in order to prevent the receiving buffer from overflowing. Flow control is performed on a per virtual channel basis.

High-performance switches generally adopt two flow control methods: Xon/Xoff flow control method or credit-based flow control method. Among them, the Xon/Xoff flow control method is generally applicable to the wormhole (Wormhole) switching mode, and for the switch adopting the virtual cut-through (Virtual CutThrough, VCT) switching mode, the reputation-based flow control method is generally used.

In the reputation-based flow control method, the sending module is notified in advance of the maximum amount of data that can be sent—the reputation value, which is in credit blocks (Credit Block). The reputation block is the basic unit of flow control, and its size is equal to a certain number of byte units, such as 64 bytes, 128 bytes, etc., and the sending module cannot send data exceeding this number.

In the process of sending data by the sending module, with the sending of data packets, the reputation value gradually decreases. When the length of the sending data packet is greater than the remaining reputation value, the sending module stops sending data until the other party of communication adds a new reputation value, and sends The module can only send data when it judges that there are enough reputation values.

In reputation-based flow control methods, the timing of sending data packets has an important impact on the performance of data communication networks. On the one hand, when the reputation value of the sending module is insufficient, if the other party of the communication has enough free space but fails to replenish the new reputation value in time, the sending module cannot send new data packets, resulting in waste of physical links and resulting in poor throughput of the switch. On the other hand, if the other party of the communication frequently sends reputation information, it will occupy a large number of physical channels, resulting in the inability to send normal data packets, which will also affect the performance of the switch. Therefore, how to determine the sending timing of the data packet is an urgent problem to be solved in the reputation-based flow control method.

In addition, in the reputation-based traffic control method in the prior art, the generation of the new reputation value is calculated based on the existing free space in the cache area. For a switch that uses an input queue, the data packet that succeeds in arbitration can also be considered as releasing buffer resources. Therefore, when calculating the new reputation value, the remaining space of the current resource includes the space that does not store any data and the space left in the buffer for the data packets that have been successfully arbitrated. By adopting the method for allocating resources in advance, the utilization rate of buffer resources can be further improved.

Contents of the invention

The purpose of the present invention is to provide a flow control system, device and method based on reputation. It improves the efficiency of the flow control method of the data communication network, and improves the utilization rate of links and buffer area resources in the switching network.

A reputation-based flow control system provided to achieve the purpose of the present invention includes a plurality of sending and receiving switch devices, the switch device includes a plurality of port modules, an arbitration module and a routing module; the port module includes a sending module, receiving module, flow control module;

The arbitration module also includes a recording submodule, configured to record the FPL value of arbitration failure according to the transmission request;

In the described reputation-based flow control system, the sending module may also include an FPL register, which is used to receive the arbitration failure FPL value recorded by the record submodule in the arbitration module, and send it to A receiving module at the receiving end;

The receiving module includes a plurality of virtual channel receiving buffer areas;

The receiving module also includes an extraction sub-module, which is used to extract the arbitration failure FPL value from the received data packet, and transmit the arbitration failure FPL value to the flow control module at the receiving end for judgment;

The receiving module is also used to continuously detect whether there is a flow control packet inserted into the data packet during the process of receiving the data packet; if so, it needs to extract the flow control packet embedded in the data packet.

The receiving module provides four parameters to the flow control module

The first parameter is used by the flow control module to judge the timing of sending the flow control packet and generate the free buffer space;

The second parameter is used to receive the new reputation value extracted by the receiving module from the flow control packet sent by the other party;

The third parameter is used to notify the flow control module that the local reputation value will decrease by 1;

The fourth parameter is the length value of the data packet to be sent.

The flow control module also includes a judging sub-module, which is used for when the sending module of the receiving end has a data packet to send to the receiving module of the sending end, the flow control module of the receiving end compares the FPL value of the arbitration failure with the remaining data packets of the flow control module of the current receiving end The local reputation value is compared with the remaining resources in the current buffer area to determine whether to send a flow control packet to the receiving module at the sending end.

In the reputation-based flow control system, the judging sub-module of the flow control module determines whether to send a flow control packet to the receiving module of the sending end, which means:

If the current remaining local reputation value is sufficient to meet the length requirement of the data packet to be sent, the flow control packet will not be sent;

Otherwise, if not satisfied, then observe and read the remaining resources in the buffer area of the receiving module of the current receiving end, and judge the remaining resources;

If the remaining resources in the buffer area can meet the length of the data packet to be sent, immediately send the flow control packet to the receiving module of the sending end;

Otherwise, the flow control packet will not be sent, and the flow control packet will be sent to the receiving module of the sending end until the length of the data packet to be sent can be satisfied.

In the reputation-based flow control system, the routing module is also used to provide the flow control module with pre-allocated space that has been successfully arbitrated but still has remaining data in the buffer area and has not been transmitted, and performs resource pre-allocation calculations .

The resource remaining includes the current idle resource situation of the cache area and the pre-allocated space resource situation;

The current idle resource of the buffer refers to the buffer space that does not store any data;

The pre-allocated space resources in the buffer area refer to buffer space that has been successfully arbitrated but still has remaining data in the buffer area and has not been completely transmitted.

Described flow control module comprises two counters, and one is the far-end credit value counter representation from receiving the opposite party's flow control packet last time, also remaining reputation value, sending module judges whether to send data packet with this reputation value; One is the local reputation value counter, which indicates the remaining local reputation value after sending the flow control packet to the other party last time.

When the recording sub-module records the FPL value of the arbitration failure, if there is no failed data packet during the arbitration process, the FPL value of the arbitration failure is assigned as the default value of the system.

The default value is the average packet length of the data packet analyzed according to the network traffic statistics, which is used as a general estimation of the packet length.

In order to realize the purpose of the present invention, a switch device based on reputation-based flow control is also provided, including a plurality of port modules, an arbitration module and a routing module; the port module includes a sending module, a receiving module, and a flow control module;

The arbitration module also includes a recording submodule, configured to provide the sending module with an arbitration failure FPL value according to the transmission request;

The default value is the average packet length of the data packets analyzed according to network traffic statistics, as a general estimate of the packet length;

In the switch device based on reputation-based flow control, the sending module can also include an FPL register, which is used to receive the arbitration failure FPL value recorded by the recording submodule in the arbitration module, and when sending a data packet, the sending module sends To the receiving module of the receiving end;

The receiving module includes a plurality of virtual channel receiving buffer areas;

The receiving module may also include an extracting sub-module, which is used to extract an arbitration failure FPL value from the received data packet, and transmit the arbitration failure FPL value to the flow control module at the receiving end for judgment.

The flow control module also includes a judging sub-module, which is used for when the sending module of the receiving end has a data packet to send to the receiving module of the sending end, the flow control module of the receiving end compares the FPL value of the arbitration failure with the remaining data packets of the flow control module of the current receiving end The local reputation value is compared with the remaining resources in the current buffer area to determine whether to send a flow control packet to the receiving module at the sending end.

In the switch device based on reputation-based flow control, the routing module is also used to provide the flow control module with the pre-allocated space that has been successfully arbitrated but still has remaining data in the buffer area and has not been transmitted, and performs resource pre-allocation. Allocation calculation.

The receiving module is also used to continuously detect whether a flow control packet is inserted into the data packet during the process of receiving the data packet;

If there is, it is necessary to extract the flow control package embedded in the data packet, and provide parameters to the flow control module according to the reputation value of the flow control package.

The arbitration failure FPL value is either a minimum arbitration failure FPL value; or an arbitration failure average FPL value; or an arbitration failure maximum FPL value.

In order to realize the object of the present invention, a flow control method based on reputation is also provided, which includes the following steps:

Step A, when the sending end has a data packet request to send, the flow control module of the sending end transmits the current remote reputation value to the arbitration module of the sending end, and the arbitration module of the sending end performs arbitration according to the transmission request and the reputation value, and at the same time, according to the transmission request Provide the arbitration failure FPL value to the sending module;

Step B, the arbitration failure FPL value is sent to the receiving module of the receiving end as a notification of the length of the data packet to be sent to the other party in the future, and then extracted by the receiving module and then sent to the flow control module of the receiving end;

Step C, the receiving module of the receiving end receives the data packet sent by the sending end, sends the arbitration failure FPL value sent by the sending end to the flow control module of the receiving end, and provides free space in the current buffer area to the flow control module of the receiving end;

Step D, the receiving end judges whether to send according to the situation of the data packets sent by the receiving end and the sending end, and the arbitration failure FPL value sent by the sending module of the sending end is compared with the remaining local reputation value of the current receiving end and the remaining resources of the current resource. The flow control packet is sent to the receiving module of the sending end.

The reputation-based flow control method may also include the following steps:

Step E, when the sending module of the receiving end sends the flow control packet, the local reputation value in the flow control module of the receiving end is updated to a new reputation value;

Step F, after receiving the flow control packet, the receiving module at the sending end transmits it to the flow control module at the sending end, and the flow control module updates the remote reputation value with a new reputation value.

The described reputation-based flow control method may also include the following steps before the step A:

In step A', the flow control module at the sending end initializes the current reputation value as the reputation value of the receiving buffer size.

In the reputation-based flow control method, the step D includes the following steps:

Step D1, when there is no data packet sent from the receiving end to the sending end, there is no link competition relationship between the flow control packet and the data packet, and the receiving end will continuously send flow control packets to the receiving module of the sending end;

Step D2, when the sending module of the receiving end has a data packet to send to the receiving module of the sending end, and there is a competitive relationship between the data packet and the flow control packet, then according to the received arbitration failure FPL value, the remaining local reputation value of the current receiving end and the remaining current resources In comparison, it is judged whether to send a flow control packet to the sender.

In the step D2, according to the received arbitration failure FPL value and the remaining local reputation value of the current receiving end and the current resource remaining, it is judged whether to send the flow control packet to the sending end, including the following steps:

Step D21, after the flow control module at the receiving end receives the arbitration failure FPL value, compare it with the current remaining local reputation value;

Step D22, if the current remaining value is sufficient to meet the length requirement of the minimum data packet, then no flow control packet is sent;

Step D23, otherwise, if not satisfied, then read the remaining resources of the buffer area in the receiving module of the current receiving end, and judge the remaining resources:

Step D24, if the remaining resources in the buffer area can satisfy the length of the data packet, send a flow control packet to the receiving module at the sending end through the sending module at the receiving end;

Step D25, otherwise do not send the flow control packet, and continue to read and judge the remaining resources of the buffer area in the receiving module of the receiving end until the length of the data packet can be satisfied, so as to send the flow control packet to the receiving end of the sending end module so far.

Said step A may also include the following steps:

If there are no lost-arbitration packets, a default value is assigned to the FPL.

The arbitration failure FPL value is either a minimum arbitration failure FPL value; or an arbitration failure average FPL value; or an arbitration failure maximum FPL value.

The beneficial effects of the present invention are: the reputation-based flow control system, device and method of the present invention, on the one hand, increase the remaining resources in the buffer area through resource pre-allocation, and on the other hand, through accurate prediction and calculation of the sending timing of flow control packets, These two factors make it impossible to blindly send flow control information during the flow control process, and only send flow control data packets immediately when it needs to be sent according to the current data flow situation to ensure efficient use of the link rate, thereby improving the flow control method and efficiency of the data communication network, and improving the utilization rate of links and buffer resources in the switching network.

Description of drawings

Fig. 1 is a schematic diagram of the data packet format of the present invention;

Fig. 2 is a schematic diagram of the flow control packet format of the present invention;

FIG. 3 is a schematic diagram of the reputation-based flow control system of the present invention;

Fig. 4 is the flow chart of the process of sending a data packet or a flow control packet by a sending module in the reputation-based flow control method of the present invention;

Fig. 5 is a flow chart of the process of receiving a data packet or a flow control packet by a receiving module in the reputation-based flow control method of the present invention;

6A is a flowchart of the working process of the remote reputation value counter of the flow control module in the reputation-based flow control method of the present invention;

6B is a flowchart of the working process of the local reputation value counter of the flow control module in the reputation-based flow control method of the present invention;

FIG. 6C is a flowchart of the process of sending a flow control packet by the flow control module in the reputation-based flow control method of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, a reputation-based flow control system, device and method of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In the reputation-based flow control system of the present invention, the link communication is composed of two peer communication entities-both ends of which are switch devices 31 or one end is a switch and the other end is a processing node-, and the two interconnected communication ports are in this In the embodiment of the invention, one of the ports is called an upstream port, and the other is called a downstream port.

Each communication port includes a sending module 33 , a receiving module 35 and a flow control module 34 . The upstream sending module 33 is connected to the downstream receiving module 35, and the data flow direction is from upstream to downstream; the downstream sending module 33 is connected to the upstream receiving module 35, and the data flow direction is downstream to upstream. Flow control (also called flow control) is independent and functionally identical in both flow directions. For the convenience of description, the embodiment of the present invention uses an example from an upstream sending end (sending end) to a downstream receiving end (receiving end) and data flow from upstream to downstream for description, but this is not a limitation of the present invention.

When the data packet is transmitted from the upstream sender to the downstream receiver, the direction of the flow control packet of the flow control is from the downstream receiver to the upstream sender.

Flow control (flow control) is a method for the receiving end to control the data transmission of the sending end in order to prevent the receiving buffer from overflowing. The size unit of flow control is Credit Block. In particular, it should be noted that flow control is performed for each virtual channel, therefore, in the embodiments of the present invention, the methods are also described for virtual channels.

At the same time, in order to illustrate the reputation-based flow control system of the present invention, the packet format transmitted in the link of the reputation-based flow control system of the present invention is firstly described.

There are two packet formats transmitted in the link: data packet format and flow control packet format.

The data packet format is shown in Figure 1, which includes the data packet header start identifier (Start of DataPacket, SDP), packet header information (Packet Information, PI), routing information (Route Information), data packet payload (Payload), packet Tail check field (CRC) and end of data packet (Endof Data Packet, EDP).

Among them, the packet header information includes the virtual channel number (VC ID), the length of the data packet and the length of the data packet to be sent (Future Packet Length, FPL) field, and the error checking and correcting (Error Checking and Correcting, ECC) field for this field. )value.

The routing information includes the destination port number to be applied for at each level. When the first-level routing is completed, the current-level routing information is discarded by the switch, and the head of the routing queue is the routing address of the next-level switch.

The end of the data packet adopts the CRC check method to check the information from the header to the last byte of the payload.

The flow control packet format is shown in Figure 2, including the Start of Flow Control Packet (SFP), the reputation field packet, and the End of Flow Control Packet (EFP). The reputation field includes a virtual channel number (VC ID), a reputation value, and Error Checking and Correcting (ECC) bits. ECC can correct errors to ensure the correctness of flow control packets.

As shown in Figure 3, the reputation-based flow control system of the present invention includes a plurality of switch devices 31 at the sending end and the receiving end, and the switch device 31 includes a plurality of port modules 32, virtual channel 0, virtual channel 1, ... , a routing module 36 of the virtual channel m, an arbitration module 37, and a cross-connection (not shown); the port module includes a sending module 33 , a receiving module 35 and a flow control module 34 .

The routing module 36 is used to apply for a corresponding port for data transmission according to the destination port provided by the data packet.

In the present invention, in order to support resource pre-allocation, the routing module 36 also provides the flow control module 34 with the data space that has been successfully arbitrated but still has remaining data in the buffer area and has not been transmitted, and performs resource pre-allocation calculation.

Pre-allocated space (PreAllocSpace: Pre-allocated Space) refers to the data space value that has been successfully arbitrated but still has remaining data in the buffer area and has not been transmitted.

The arbitration module 37 is used for arbitrating and judging the data packets with input requests according to the priority and reputation value.

The arbitration module 37 will authorize the sending module 33 to the input request with the highest priority and whose data packet length is smaller than the current remote reputation value provided by the flow control module 34 .

If the award is successful, the data packet will reach the destination port through the cross-connection; if the award is not successful, the data packet will also be stored in the receiving buffer to wait for the result of the next arbitration.

The arbitration module 37 in the present invention also includes a record sub-module 38, which is used to record the data packet length (FPL) value of the arbitration failure according to the input request.

The data packet length value of the arbitration failure, that is, the arbitration failure FPL value, can be the data packet length value with the smallest length among all the arbitration failure data packets, that is, the minimum FPL value of the arbitration failure; it can also be the length value of all the arbitration failure data packet length values The average value is the average FPL value of arbitration failure; it can also be the longest data packet length value of all arbitration failures, that is, the maximum FPL value of arbitration failure. It may also be other determined data packet length (FPL) values of arbitration failure and the like.

The arbitration failure FPL value indicates the length value of the data packet that the sending module 33 of the upstream sending end will send to the receiving module 35 of the downstream receiving end, and may also be referred to as a future FPL value.

In the present invention, the present invention is described by taking the arbitration failure FPL value as an example of the minimum FPL value of arbitration failure, but this embodiment is also applicable to the average FPL value of arbitration failure, the maximum FPL value of arbitration failure, or other determined arbitration failures. Implementation of packet FPL values.

The recording sub-module 38 provides an arbitration-failed FPL value to the sending module 33 according to the input request, and the value is the length value of the data packet of the arbitration-failure.

Preferably, if there is no failed data packet in the arbitration process, then the arbitration failure FPL value is assigned a default value, and the default value is the average packet length of the data packet analyzed according to network traffic statistics, as a pair of packet length general estimate of .

The sending module 33 is used for sending data packets and flow control packets.

After the sending module 33 completes the link initialization process, it enters the state of waiting to send; if there is a data packet sending request, the sending module 33 will send the data packet according to the data packet format; meanwhile, the sending module 33 detects whether there is a flow control packet from time to time Request to send, even in the process of sending the data packet, if there is a flow control packet request, the sending module 33 can also insert the flow control packet into the data packet to ensure the timeliness of the flow control information (ie send the flow control packet in time).

The new credit value (New_Credit) in the flow control packet sent by the sending module 33 is provided by the flow control module 34 .

The sending module 33 simultaneously detects whether the sent data has reached 1 reputation block, and if so, notifies the local flow control module 34 to decrement the current remote reputation value by 1.

In order to support the reputation-based flow control system of the present invention, the sending module 33 also embeds the arbitration failure FPL value (future FPL value) provided by the arbitration module 37 into the data packet and sends it out.

This arbitration failure FPL value is used as the data packet length that the receiving module 35 of the other side's receiving end will send in the future, and is transmitted to the receiving module 35 of the other side's receiving end by the sending module 33, and then is extracted by the receiving module 35 of the receiving end and delivered to the flow control of the receiving end. Module 34.

Preferably, the sending module 33 also includes an FPL register 39, which is used to receive the arbitration failure FPL value recorded by the recording submodule 38 in the arbitration module 37, and is sent to the receiver at the receiving end by the sending module 33 when sending a data packet. Module 35.

The receiving module 35 is used to extract data packets and flow control packets from the received data stream.

After the receiving module 35 completes the link initialization process, it enters the waiting state for receiving.

The receiving module 35 includes virtual channel 0, virtual channel 1, . . . , virtual channel m receiving buffers for temporarily storing data packets on the network.

During the process of receiving the data packet, the receiving module 35 continuously detects whether there is a flow control packet inserted into the data packet; if so, extracts the flow control packet embedded in the data packet.

In the present invention, according to the received flow control packet, the receiving module 35 is continuously detecting whether a flow control packet is inserted into the data packet during the process of receiving the data packet. If there is, it is necessary to extract the flow control package embedded in the data package.

The receiving module 35 provides four parameters to the flow control module 34:

The first parameter is Creditof (FreeSpace), wherein, FreeSpace represents free space in the current cache area, and Creditof (FreeSpace) is to carry out normalization operation to FreeSpace according to the reputation block size, and this parameter is used for flow control module 34 to carry out flow control packet sending Opportunity judgment and generation of new local reputation value;

The second parameter is New_Credit, and New_Credit represents the new credit value extracted by the receiving module 35 from the flow control packet sent by the other party. The receiving module 35 will notify the flow control module 34 to update the remote reputation value, which means the maximum amount of data that the local sending module 33 can send.

The third parameter is to notify the traffic control module 34 that the local reputation value is decreased by 1. The receiving module 35 notifies the flow control module 34 to decrement the local reputation value by 1 whenever it receives a reputation block data amount.

The 4th parameter is the arbitration failure FPL value (is about to send data packet length value, future FPL value), receiving module 35 will extract the arbitration failure FPL value of notice in advance from the received data packet, send this value to flow control Module 34.

Preferably, the receiving module 35 further includes an extracting sub-module 310, configured to extract an arbitration failure FPL value from the received packet data, and transmit the arbitration failure FPL value to the flow control module 34 at the receiving end for judgment.

The flow control module 34 is used to provide the current far-end reputation value to the arbitration module 37 during the sending process, and provides the flow control parameter to the sending module 33, and requests the sending module 33 to send this value to the receiving end; The receiving flow control parameter of the receiving end - the new credit value (New_Credit) - is assigned to the remote credit value in the flow control module.

The flow control module 34 includes two counters. One is the remote credit value counter 312 (RemoteCreditCnt), and the counter 312 indicates the remaining credit value after receiving the other party's flow control packet last time. Sending module 33 judges whether to send data packet with this reputation value; In size, the counter 313 is approximately equal to the value of the remote reputation counter 312 of the other party, which is an estimate of the value. With the counter 313, the local flow control module 34 can estimate the amount of data that the other party's sending module 33 can send size.

The flow control module 34 decrements the remote credit value counter 312 (RemoteCreditCnt) by 1 according to the instruction of the sending module 33, and decrements the local credit value counter 313 (LocalCreditCnt) by 1 according to the instruction of the receiving module 35.

In the present invention, the flow control module 34 also judges an appropriate time to send the flow control packet according to the current free space in the buffer area and the pre-allocated free space. On the one hand, this timing can ensure the uninterrupted flow of data packets; on the other hand, it can also minimize the overhead of flow control information on physical bandwidth, reduce the impact on normal data communication, improve data throughput, reduce the average waiting time of data packets, and adapt to Effect of different data streams on flow control.

Preferably, the flow control module 34 also includes a judging sub-module 311, which is used for receiving the arbitration from the sending module 33 of the sending end when the sending module 33 of the receiving end has a data packet to send to the receiving module 35 of the sending end. The failed FPL value is compared with the remaining local reputation value of the current receiving end and the current resource remaining to determine whether to send a flow control packet to the upstream port module.

After the flow control module 34 of the receiving end receives the arbitration failure FPL value, it is compared with the current remaining reputation value:

If the current remaining value is sufficient to meet the length requirements of the data packet, the flow control packet will not be sent;

Otherwise, if not satisfied, then read the remaining resources of the buffer area in the receiving module 35 of the current receiving end, including the current idle resource situation and the pre-allocated space resource situation, and judge the remaining resource situation:

If the remaining resources of the buffer area can satisfy the data packet length, the flow control packet is immediately sent to the receiving module 35 of the sending end;

Otherwise, the flow control packet will not be sent, and continue to read and judge the remaining resources of the buffer area in the receiving module 35 of the current receiving end until the length of the data packet can be satisfied, and send the flow control packet to the receiving module 35 of the sending end.

When the sending module 33 of the downstream receiving end sends the flow control packet, the local reputation value counter 313 (LocalCreditCnt) in the flow control module 34 of the downstream receiving end is updated to a new reputation value;

After the receiving module 35 of the upstream sending end receives the flow control packet, it sends it to the flow control module 34 of the sending end, and the flow control module 34 updates the remote credit value counter 312 (RemoteCreditCnt) to a new credit value.

In this way, the reputation-based flow control system and device of the present invention, through the judging sub-module 311 in the flow control module 34, judges, selects the timing of sending the flow control packet, and selects a suitable timing to send, so as to achieve timely and accurate flow control effect.

The reputation-based flow control method of the present invention will be further described in detail below in conjunction with the reputation-based flow control system and device of the present invention, as shown in Figure 4, Figure 5, Figure 6A, Figure 6B and Figure 6C:

Wherein, Fig. 4 is a flow chart of the sending module 33 sending a data packet or a flow control packet process; Fig. 5 is a flow chart of a receiving module 35 receiving a data packet or a flow control packet process; Fig. 6A is a flow control module 34 remote reputation value counter 312 work Process flow chart; FIG. 6B is a flow chart of the working process of the local reputation value counter 313 of the flow control module 34; FIG. 6C is a flow chart of the process of the flow control module 34 sending the flow control packet.

Step S100, as shown in Fig. 4 and Fig. 5, in the initialization phase, the flow control module 34 of the upstream sender initializes the remote reputation counter 312 (RemoteCreditCnt) to the reputation value of the receiving buffer size, represented by creditof (RxBuf).

Among them, creditof(X) means to normalize the X variable according to the credit value.

RxBuf represents the size of the buffer area in the receiving module 35 of the receiving end, and the size of the free space of the receiving buffer area in the receiving module 35 at the initialization stage is the size of the receiving buffer area itself.

At the same time, the local reputation value counter 313 (LocalCreditCnt) of the flow control module 34 at the downstream receiving end is also initialized to creditof (RxBuf).

Step S200, as shown in FIG. 4, FIG. 5, FIG. 6A, FIG. 6B, and FIG. 6C, is a normal working stage.

Step S210, when the sending module 33 of the sending end requests to transmit data packets to the receiving end block of the receiving end, the flow control module 34 of the sending end sends the credit value in the current remote credit counter (RemoteCreditCnt) to the arbitration module 37 of the sending end, and the sending end arbitrates The module 37 performs arbitration according to the transmission request and the reputation value, and at the same time, provides the sending module 33 with the FPL value of the arbitration failure according to the transmission request.

In order to ensure fairness, the arbitration module 37 adopts the method with the lowest priority of the latest service to ensure fairness. At the same time, the arbitration module 37 also considers the length of the data packet, and compares the length of the data requested for transmission with the current remote reputation value.

The arbitration module 37 will authorize the data packet with the highest priority and the packet length smaller than the reputation value, so that the data packet can reach the destination port.

The arbitration module 37 will also record the FPL value in the arbitration failure and send it to the FPL register 39 in the sending module 33 of the sending end. If there is no arbitration-lost packet, the arbitration-lost FPL value is assigned a default value.

The sending module 33 at the upstream sending end will send the data packet with successful arbitration according to the data packet format, and at the same time, the FPL value will also be sent with the data packet if the arbitration fails.

Simultaneously, every time send the data amount of a reputation block, then the sending module 33 of sending end notifies the flow control module 34 of sending end that current far-end reputation value is subtracted 1 (RemoteCreditCnt=RemoteCreditCnt-1), when this reputation value is reduced to no one After the sending request can be satisfied, the sending module 33 cannot send the virtual channel data, and the virtual channel is in a stop waiting state.

Step S220, the arbitration failure FPL value is sent to the receiving module 35 of the receiving end as the length of the data packet to be sent in the future to inform the other party, and then extracted by the receiving module 35 and then sent to the flow control module 34 of the receiving end.

The sending module 33 at the sending end receives the arbitration failure FPL value recorded by the arbitration module 37, and when sending the data packet, the sending module 33 embeds the arbitration failure FPL value into the data packet, and sends it to the receiving module 35 at the receiving end.

Step S230, the receiving module 35 of the receiving end receives the packet sent by the sending end, sends the arbitration failure FPL value sent by the sending end to the flow control module 34 of the receiving end, and provides free space (FreeSpace) in the current buffer area to the flow control of the receiving end Module 34.

The routing module 36 at the receiving end also provides the flow control module 34 with the pre-allocated space of the untransmitted data space that has been successfully arbitrated but still has remaining data in the buffer area, and performs resource pre-allocation calculations.

At the same time, when the receiving module 35 of the downstream receiving end receives a data flow of a credit block size, it notifies the flow control module 34 of the downstream receiving end that the current local credit value is decreased by 1 (LocalCreditCnt=LocalCreditCnt-1).

Step S240, the receiving end compares the FPL value of the arbitration failure sent by the sending module 33 of the sending end with the remaining local reputation value of the current receiving end and the current resource remaining according to the data packet transmission of the downstream receiving end and the upstream sending end, It is judged whether to send the flow control packet to the receiving module 35 of the sending end.

Step S241, when there is no data packet sent from the downstream receiving end to the upstream sending end, there is no link competition relationship between the flow control packet and the data packet, and the downstream receiving end will continuously send flow control packets to the receiving module of the upstream sending end 35. Ensure the timeliness of flow control information.

As an implementable way, the reputation value included in the flow control package is:

New_Credit = FreeCredit _dw = creditof(FreeSpace) + creditof(PreAllocSpace)

Among them, FreeCredit _dw represents the downstream free credit value;

FreeSpace indicates that there is no free space for storing any data;

PreAllocSpace indicates the remaining space in the buffer area in the successfully scheduled data packets;

Step S242, when the sending module 33 of the downstream receiving end has a data packet to send to the receiving module 35 of the upstream sending end, the data packet of the receiving end and the flow control packet have a competitive relationship, then according to the received arbitration failure FPL value and the remaining reputation of the current receiving end Compare the values to determine whether to send a flow control packet to the sender.

In step S242, according to the received arbitration failure FPL value compared with the remaining credit value of the current receiving end, it is judged whether to send the flow control packet to the sending end, which specifically includes the following steps:

Step S2421, after the flow control module 34 of the receiving end receives the arbitration failure FPL value, compare it with the current remaining reputation value;

Step S2422, if the current remaining value is sufficient to meet the length requirement of the data packet, that is, the remaining value is greater than the arbitration failure FPL value, then no flow control packet is sent;

Step S2423, otherwise, if not satisfied, then read the remaining resources of the buffer area in the receiving module 35 of the current receiving end, including the current idle resources and pre-allocated space resources, and judge the remaining resources:

The pre-allocated space refers to the untransmitted data space value that has been successfully arbitrated but still has remaining data in the buffer.

Idle resources refer to the size of buffer space in the buffer area of the receiving module 35 that is not used or has released buffered data.

Step S2424, if the remaining resources in the buffer area can satisfy the length of the data packet to be sent, immediately send the flow control packet to the receiving module 35 of the sending end through the sending module 33 of the receiving end;

Step S2425, otherwise do not send the flow control packet, and continue to read and judge the remaining resources of the buffer area in the receiving module 35 of the current receiving end until the sending requirement of the length of the data packet can be met, so as to send the flow control packet to the sending end until the receiving module 35.

As a way that the present invention can be implemented, as shown in Figure 6C, in order to prevent the upstream sender from disconnecting due to no reputation value, and to avoid the waste of link bandwidth caused by sending redundant flow control packets, according to formula (1) and The condition of formula (2) determines whether to send the flow control packet to the upstream sender.

If the remaining reputation value of the downstream receiver is:

RemainCredit _dw = LocalCreditCnt;

The free space in the receiving buffer of the downstream receiving end is:

FreeCredit _dw = creditof(FreeSpace)+creditof(PreAllocSpace)

then when:

RemainCredit _dw ＜ creditof(FPL)+creditof(RTT×BW) (1)

FreeCredit _dw ＞＝creditof(FPL)+creditof(RTT×BW) (2)

When established, the flow control module 34 at the receiving end sends a flow control packet through the sending module 33 .

Creditof (FPL) is to normalize FPL according to the credit block size.

That is, when formula (1) and formula (2) are satisfied at the same time, the flow control module 34 of the receiving end sends a flow control packet to the receiving module 35 of the sending end through the sending module 33 of the receiving end, which contains a new flow control reputation value FreeCredit _dw , the The value will update the remote credit value RemoteCreditCnt=FreeCredit _dw of the flow control module 34 at the upstream sending end; meanwhile, the downstream will also update the local credit value LocalCreditCnt=FreeCredit _dw .

That is to say, if the current downstream receiving end still has enough space to accommodate the FPL-length data packet, the sending module 33 of the upstream sending end will continue to send, and the link will not be interrupted.

Preferably, due to the link delay between the upstream sending end and the downstream receiving end, creditof(RTT×BW) is also considered to exclude the difference.

Among them, RTT (Round Trip Time) represents the loopback time of the physical link;

BW represents the physical link bandwidth;

RTT×BW represents the flow control information included in the loopback time.

Creditof(RTT×BW) indicates that RTT×BW is normalized according to the credit block size.

Step S250, when the sending module 33 of the downstream receiving end sends the flow control packet, the credit value in the local reputation value counter 313 (LocalCreditCnt) in the flow control module 34 of the downstream receiving end is updated to a new reputation value FreeCredit _dw , i.e. LocalCreditCnt=FreeCredit _dw ;

Step S260, after the receiving module 35 of the upstream sending end receives the flow control packet, it transmits it to the flow control module 34 of the sending end, and the flow control module 34 updates the credit value in the current far-end credit value counter 312 (RemoteCreditCnt) to a new one. The reputation value of FreeCredit _dw , that is, RemoteCreditCnt=FreeCredit _dw .

In the reputation-based flow control method of the present invention, the flow control module 34 at the downstream receiving end uses the arbitration failure FPL value to compare the current remaining reputation value. If the current remaining value is sufficient to meet the length requirement, the flow control packet will not be sent; on the contrary, if it cannot be satisfied, observe the remaining resources of the current buffer area, including the remaining resources of the current free and pre-allocated space; if the resources can meet the data packets to be sent length, the data packet is sent immediately, otherwise no flow control packet is sent. It will not blindly send flow control information, but will only send flow control packets immediately when it needs to be sent according to the current data flow situation, so as to ensure efficient utilization of the link.

The specific embodiments of the present invention have been described and illustrated above, and these embodiments should be considered as exemplary only, and are not used to limit the present invention, and the present invention should be interpreted according to the appended claims.

Claims (23)

1. A flow control system based on reputation, comprising a plurality of sending and receiving switch devices, the switch device includes a plurality of port modules, an arbitration module and a routing module; the port module includes a sending module, a receiving module, a flow control module; The receiving module includes a plurality of virtual channel receiving buffer areas; It is characterized by: The arbitration module also includes a recording submodule, configured to record the FPL value of arbitration failure according to the transmission request; The flow control module also includes a judging sub-module, which is used for when the sending module of the receiving end has a data packet to send to the receiving module of the sending end, according to the received arbitration failure FPL value sent by the sending module of the sending end, and the remaining value of the current receiving end The local reputation value is compared with the current remaining resources to determine whether to send a flow control packet to the receiving module at the sending end. 2. The reputation-based flow control system according to claim 1, characterized in that: The sending module also includes an FPL register, which is used to receive the arbitration failure FPL value recorded by the recording sub-module in the arbitration module, and is sent to the receiving module at the receiving end by the sending module when sending a data packet; The receiving module further includes an extracting sub-module, which is used to extract the arbitration failure FPL value from the received packet data, and transmit the arbitration failure FPL value to the flow control module at the receiving end for judgment. 3. The reputation-based flow control system according to claim 1 or 2, wherein the judging submodule judges whether to send a flow control packet to the receiving module of the sending end, which refers to: If the current remaining value is sufficient to meet the length requirement of the data packet to be sent, the flow control packet will not be sent; Otherwise, if not satisfied, then observe and read the remaining resources in the buffer area of the receiving module of the current receiving end, and judge the remaining resources; If the remaining resources in the buffer area can meet the length of the data packet to be sent, immediately send the flow control packet to the receiving module of the sending end; Otherwise, the flow control packet will not be sent, and the flow control packet will be sent to the receiving module of the sending end until the length of the data packet to be sent can be satisfied. 4. The reputation-based flow control system according to claim 3, characterized in that: The routing module is also used to provide the flow control module with pre-allocated space that has been successfully arbitrated but still has remaining data in the buffer area and has not been transmitted, and performs resource pre-allocation calculations. 5 . The reputation-based flow control system according to claim 4 , wherein the remaining resources include current idle resources and pre-allocated space resources. 6 . 6. The reputation-based flow control system according to claim 4, wherein the receiving module is also used to continuously detect whether a flow control packet is inserted into the data packet during the process of receiving the data packet; If there is, it is necessary to extract the flow control package embedded in the data packet, and provide parameters to the flow control module. 7. The reputation-based flow control system according to claim 6, wherein the parameters include the following four parameters: The first parameter is used by the flow control module to judge the timing of sending the flow control packet and generate the current free cache space of the new local reputation value; The second parameter is used to receive the new reputation value extracted by the receiving module from the flow control packet sent by the other party; The third parameter is used to notify the flow control module that the local reputation value will decrease by 1; The fourth parameter is the arbitration failure FPL value. 8. The reputation-based flow control system according to claim 1 or 2, wherein the flow control module includes two counters, one of which is a remote reputation value counter indicating that the flow control packet from the other party has been received last time. , and the remaining reputation value, the sending module uses the reputation value to judge whether to send the data packet; the other is the local reputation value counter, which represents the remaining reputation value locally after sending the flow control packet to the other party last time. 9. The reputation-based flow control system according to claim 1 or 2, wherein when the record submodule records the arbitration failure FPL value, if there is no failed data packet in the arbitration process, then the arbitration failure FPL value is assigned the system default value. 10. The reputation-based flow control system according to claim 9, wherein the default value is the average packet length of data packets analyzed according to network traffic statistics, as a general estimate of the packet length. 11. The reputation-based flow control system according to claim 1 or 2, wherein the FPL value for arbitration failure is either the minimum FPL value for arbitration failure; or the average FPL value for arbitration failure; or the maximum FPL value for arbitration failure FPL value. 12. A switch device based on reputation-based flow control, comprising a plurality of port modules, an arbitration module and a routing module; the port module includes a sending module, a receiving module, and a flow control module; The receiving module includes a plurality of virtual channel receiving buffer areas; It is characterized by: The arbitration module also includes a recording submodule, configured to provide the sending module with an arbitration failure FPL value according to the transmission request; The flow control module also includes a judging sub-module, which is used for when the sending module of the receiving end has a data packet to send to the receiving module of the sending end, according to the received arbitration failure FPL value sent by the sending module of the sending end, and the remaining value of the current receiving end Comparing the reputation value with the current remaining resources, it is judged whether to send a flow control packet to the receiving module of the sending end. 13. The switch device based on reputation-based flow control according to claim 12, characterized in that: The sending module also includes an FPL register, which is used to receive the arbitration failure FPL value recorded by the recording sub-module in the arbitration module, and is sent to the receiving module at the receiving end by the sending module when sending a data packet; The receiving module further includes an extracting sub-module, which is used to extract the arbitration failure FPL value from the received packet data, and transmit the arbitration failure FPL value to the flow control module at the receiving end for judgment. 14. The switch device based on reputation-based flow control according to claim 12 or 13, characterized in that, the routing module is also used to provide the flow control module with information that has been successfully arbitrated but still has remaining data in the cache area. , the untransmitted pre-allocated space is used for resource pre-allocation calculation. 15. The switch device based on reputation-based flow control according to claim 14, wherein the receiving module is also used to continuously detect whether a flow control packet is inserted into the data packet during the process of receiving the data packet; If there is, it is necessary to extract the flow control package embedded in the data packet, and provide parameters to the flow control module according to the reputation value of the flow control package. 16. The switch device based on reputation-based flow control according to claim 12 or 13, wherein the FPL value of the arbitration failure is either the minimum FPL value of the arbitration failure; or the average FPL value of the arbitration failure; or the arbitration failure FPL value; Failed max FPL value. 17. A reputation-based flow control method, characterized in that, comprising the following steps: Step A, when the sending module at the sending end requests to transmit data packets to the receiving module at the receiving end, the flow control module at the sending end transmits the current remote reputation value to the arbitration module at the sending end, and the arbitration module at the sending end performs arbitration according to the transmission request and the reputation value, At the same time, according to the transmission request, the arbitration failure FPL value is provided to the sending module; Step B, the arbitration failure FPL value is sent to the receiving module of the receiving end, and then extracted by the receiving module and sent to the flow control module of the receiving end; Step C, the receiving module of the receiving end receives the data packet sent by the sending end, sends the arbitration failure FPL value sent by the sending end to the flow control module of the receiving end, and provides free space in the current buffer area to the flow control module of the receiving end; Step D, the receiving end judges whether to send a flow control packet to the sending end based on the data packets sent by the receiving end and the sending end, and compares the FPL value of the failed arbitration sent by the sending module of the sending end with the remaining reputation value of the current receiving end terminal receiving module. 18. The reputation-based flow control method according to claim 17, further comprising the following steps: Step E, when the sending module of the receiving end sends the flow control packet, the current local reputation value in the flow control module of the receiving end is updated to a new reputation value; Step F, after receiving the flow control packet, the receiving module at the sending end transmits it to the flow control module at the sending end, and the flow control module updates the current remote reputation value with a new reputation value. 19. The flow control method based on reputation according to claim 18, characterized in that, before the step A, the following steps are also included: In step A', the flow control module at the sending end initializes the current reputation value as the reputation value of the receiving buffer size. 20. The reputation-based flow control method according to any one of claims 17 to 19, wherein said step D comprises the following steps: Step D1, when there is no data packet sent from the receiving end to the sending end, there is no link competition relationship between the flow control packet and the data packet, and the receiving end will continuously send flow control packets to the receiving module of the sending end; Step D2, when the sending module of the receiving end has a data packet to send to the receiving module of the sending end, and there is a competition between the data packet and the flow control packet, it is judged whether the received arbitration failure FPL value is compared with the remaining reputation value of the current receiving end. Send a flow control packet to the sender. 21. The reputation-based flow control method according to claim 20, wherein in the step D2, it is judged whether to send a flow control packet according to the comparison between the received arbitration failure FPL value and the remaining reputation value of the current receiving end to the sender, including the following steps: Step D21, after the flow control module at the receiving end receives the arbitration failure FPL value, compare it with the current remaining reputation value; Step D22, if the current remaining value is sufficient to meet the length requirement of the data packet, then no flow control packet is sent; Step D23, otherwise, if not satisfied, then read the remaining resources of the buffer area in the receiving module of the current receiving end, and judge the remaining resources: Step D24, if the remaining resources in the buffer area can satisfy the length of the data packet, send a flow control packet to the receiving module at the sending end through the sending module at the receiving end; Step D25, otherwise do not send the flow control packet, and continue to read and judge the remaining resources of the buffer area in the receiving module of the receiving end until the length of the data packet can be satisfied, so as to send the flow control packet to the receiving end of the sending end module so far. 22. The reputation-based traffic control method according to any one of claims 17 to 19, wherein said step A further comprises the following steps: If there is no arbitration-lost data packet, the arbitration-lost FPL value is assigned a system default value. 23. The reputation-based flow control method according to any one of claims 17 to 19, wherein the FPL value of the arbitration failure is either the minimum FPL value of the arbitration failure; or the average FPL value of the arbitration failure; or the arbitration failure FPL value; Failed max FPL value.

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