JP2002176464A - Network interface device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit transmission data to a network 3 at high speed by increasing a transfer rate of the transmission data transferred from communication equipment 2 to a network interface device 1. SOLUTION: The communication unit 2 gives transmission data together with a transmission descriptor including control information with respect to the transmission data to the network interface device 1 and the network interface device 1 transmits the transmission data received on the basis of the received transmission descriptor to the network 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network interface device for transferring data in, for example, a local area network (LAN) communication system or a computing cluster system.
In particular, the present invention relates to a network interface device for realizing high-speed transmission of a message data packet from a system memory to a network in a computer terminal constituting a LAN communication system, a computing cluster system, or the like.

[0002]

2. Description of the Related Art In recent years, for example, the transmission speed of a LAN is 100
Mbps (Mega Bit Per Second) is becoming mainstream, and the improvement in LAN transmission speed has enabled high-speed transmission of large amounts of multimedia data such as video and audio. At the same time, the performance of personal computers (PCs) has been significantly improved in recent years, and CPUs (Central Processing Uni
The calculation speed of t) has been increased, and the capacity of the memory has become much larger than before.

[0003] Under such circumstances, new applications such as a desktop conference system for performing a conference between remote locations using a PC and a system for performing a remote education have been realized. In recent years, a computing PC cluster system has been realized in which a plurality of PCs are connected via a LAN and large-scale computations are processed in parallel / parallel / distributed by each PC (node). Here, the calculation PC cluster system can be configured at a very low cost by using a commercially available PC and a network interface device, and can exhibit calculation performance comparable to a supercomputer. This is a technology that is currently receiving much attention.

[0004] In the future, demands for speeding up the network from all kinds of applications will continue to increase, and the transition to a LAN having a transmission speed of 1 Gbps is rapidly progressing. In addition, IEEE (Institute of E
10Gb by Electrical and Electronics Engineers)
ps Ethernet (registered trademark) (Ethernet)
(Registered trademark)) standardization work has already started.

A device for connecting a computer terminal to a LAN, that is, a network interface card (NI)
C: Network Interface Card) has a function of transmitting transmission data from the host system of the computer terminal to the network and a function of transferring received data coming from the network to the host system of the computer terminal.

Here, when the transmission speed of the LAN is improved as at present, the host system of the computer terminal and the NIC
There is a possibility that the data transfer speed between the two will become a bottleneck in communication between networks.
For example, in a computing PC cluster system, the data transfer efficiency from a host system of a certain computer terminal to the NIC is low, and the speed at which message data packets are transferred becomes slow, so that transmission cannot be performed smoothly. In such a case, the network continues to be unused even though the network traffic has room, or another computer terminal has too much computational capacity because no message data packet arrives. Things can happen. In such a situation, the speeding up of the network and the performance improvement of the computer terminal cannot be utilized.

[0007] Current NICs often function with IC (Integrated Circuit) chips called LAN controllers. FIG. 9 shows a configuration example of a conventional typical LAN controller 61 for Ethernet, and also shows a host system 62 and a network 63 connected to the LAN controller 61.
It should be noted that, for example, a LAN controller marketed by Digital Equipment Corporation or Intel Corporation also has a configuration as shown in FIG.

A LAN controller 61 shown in FIG. 1 includes a peripheral component interconnect (PCI) having an interface function with a host system 62.
ent Interconnect) bus interface 71 and a DMA (Direct Memory) for controlling access to the memory.
Access) controller 72, a multi-purpose register 73 for storing data, a first-in first-out (FIFO) buffer memory 74 for storing data for transmission, and a media access control (MAC) for controlling media access. An SIA (Serial Interface Adapter) interface 76 having an interface function between an Access Control (Controller) controller 75 and a network 63, and an MII (Media Independent Interface) having an interface function between the network 63
ace) interface 77, a reception FIFO buffer memory 78 for storing reception data, and a data control unit 79 for controlling each of the processing units 71 to 78.

The host system 62 shown in FIG. 1 is provided with a CPU 80 for executing various processes and a system memory 81 for storing data. Also, L
The SIA interface 76 and the MII interface 77 provided in the AN controller 61
The PCI bus interface 71 is connected to a CPU 80 and a system memory 81 provided in the host system 62.

[0010] As shown in FIG.
The N controller 61 has a PCI bus interface 71 of mostly 32 bits. At present, the clock frequency of the PCI bus is generally 33 MHz, so that the maximum data transfer rate between the host system 62 and the LAN controller 61 is 133 Mbytes / sec.
Recently, a device having a 64-bit, 66 MHz PCI bus interface has appeared.

Further, as shown in FIG. 1, the LAN controller 61 usually has a DMA controller 72, and such a LAN controller 61 can be a bus master. Although one DMA controller 72 is shown in the example of FIG. 1 for convenience of description, generally, DMA controllers for two channels are provided for transmission and reception. These DMA controllers operate independently of each other, and operate in the system memory 8 in the host system 62.
1 is used for data transfer between the two.

The LAN controller 6 shown in FIG.
In 1, a received frame flowing from the network 63 is input through the SIA interface 76 or the MII interface 77, subjected to necessary processing by the MAC controller 75, and temporarily stored in the receiving FIFO buffer memory 78. The PCI bus interface 71 is then read from the memory 78 and
Is transferred to the host system 62 via the.

The transmission FIFO buffer memory 74
Is a buffer memory for temporarily storing transmission data before sending it to the network 63. In the LAN controller 61 shown in the figure, the transmission frame transferred from the host system 62 via the PCI bus interface 71 is temporarily stored in the transmission FIFO buffer memory 74 and then required by the MAC controller 75. After that, it is transmitted to the network 63 via the SIA interface 76 or the MII interface 77.

The LAN controller 6 shown in FIG.
In 1, the data control unit 79 manages the transfer of a data structure including information such as a transmission frame and a reception frame, and a command and status from the host system 62 to the LAN controller 61.

The LAN controller 6 shown in FIG.
In 1, a multi-purpose register 73 for storing information such as the above-mentioned commands and status is provided. Here, the multipurpose register 73 is usually a control / status register (CSR).
egsiter)), which is mapped on the system memory 81 of the host system 62.
Therefore, in such a configuration, the LAN controller 61
And the host system 62 can perform read / write.

Next, in the configuration shown in FIG. 9, an outline of the most general mechanism of the process of transferring a transmission frame from the host system 62 of the PC to the LAN controller 61 will be described below. That is, in general, a data structure called a transmission descriptor is used to transfer a transmission frame from the host system 62 of the PC to the LAN controller 61.

A plurality of transmission descriptors are assigned to the system memory 81 of the host system 62 by a device driver when the PC is started. Here, FIG. 10 shows an example of a general structure of a transmission descriptor. This transmission descriptor has a size field 91 for storing information of a size (Size) of a transmission frame.
, A command field 92 for storing command (Command) information, a status field 93 for storing status (Status) information, and a buffer address (Buffer Address) of a transmission frame.
s) buffer address field 94 for storing information
It is composed of

In many cases, information on an error that has occurred during transfer of a transmission frame is set in the status field 93. In the command field 92, parameters for controlling the operation of the LAN controller 61 are usually prepared. Specifically, for example, a bit for instructing to suspend transmission of a transmission frame after transmission of the current frame, or when there are several modes in the transmission frame transmission method, transmission should be performed in any mode There are provided bits for designating whether or not.

In the size field, information on the size of the transmission frame is set. In the buffer address field 94, information indicating the start address of the transmission frame prepared on the system memory 81 of the host system 62 is set.

As shown in FIG. 11, in this example,
The transmission descriptor has a ring structure, and is continuously allocated in the system memory 81 of the host system 62 in a format as shown in FIG. Specifically, in the system memory 81 of the host system 62, for example, the “0” to “n” th transmission descriptors 101a
The transmission buffers 101a to 101d are arranged continuously, and the transmission buffers 101a to 101d indicate the start address, and the standby buffers (transmission standby buffers) 102a to 102d of the "0" to "n" th transmission frames.
Is prepared.

First, upon receiving a transmission request from a higher level, the device driver of the host system 62 sends a transmission command (TX CMD:
Transmit Command), and at the same time, notifies the LAN controller 61 of the address of the transmission descriptor used for transmission. Normally, the LAN controller 61
This instruction and address are transmitted to the LAN controller 61 by generating a target write cycle of the PCI cycle for the CSR 73. Note that the target indicates that the processing is performed unilaterally by being controlled by another device, and the master indicates that the processing is executed by taking the initiative of the transaction.

When the LAN controller 61 receives the address of the transmission descriptor, the host system 62
The transmission descriptor is read from that address in the system memory 81 and stored in the multi-purpose register 73.
Normally, a master read cycle of a PCI cycle is executed to copy the transmission descriptor.

Next, the LAN controller 61 refers to the contents described in the read transmission descriptor and reads the size field 91 from the address in the system memory 81 specified by the buffer address field 94.
Reads data of the size specified by
The data is stored in the O buffer memory 74.

In this way, the transmission data is
When prepared in the O buffer memory 74, in the LAN controller 61, the MAC controller 75 sends the transmission data to the network 63 via the SIA interface 76 or the MII interface 77.

When the transmission of the transmission data to the network 63 is completed, in the LAN controller 61, the data controller 79 updates the status field 93 of the transmission descriptor and writes the transmission descriptor into the system memory 81 of the host system 62. Generate an interrupt after returning. As a result, the device driver of the host system 62 can determine, based on the rewritten transmission descriptor, whether the transmission processing using the transmission descriptor has succeeded or failed. Further, the device driver of the host system 62 knows that the transmission descriptor may be used for the next transmission.

FIG. 12 shows another example of the general structure of the transmission descriptor. The transmission descriptor has, for example, a size field 111, a command field 112, and a status similar to those shown in FIG. A field 113 and a link address (Link Address) for storing information on a link destination address
And a field 114.

The transmission descriptor shown in FIG. 12 is an example of a transmission descriptor scatteredly prepared on the system memory 81 of the host system 62, and information of a link address is written in the transmission descriptor. Here, the link address information specifies the address of the transmission descriptor to be used next.

That is, as shown in FIG. 13, for example, the transmission descriptor of this example has a so-called chain structure, whereby the address on the system memory 81 in which the next transmission descriptor to be used is stored is known. Can be. Specifically, as shown in the figure, the address of the next “1” -th transmission descriptor 121b is specified in the “0” -th transmission descriptor 121a, and the next “1” -th transmission descriptor 121b is specified in the next “1” -th transmission descriptor 121b. Each transmission descriptor specifies the address of the next transmission descriptor to be used, such as the address of the 2 ″ -th transmission descriptor 121c.

The transmission descriptor of this example does not include a buffer address field. In this case, as shown in FIG. 13, in the system memory 81 of the host system 62, each transmission descriptor 121a
To 121c are buffer memories (transmission waiting buffers) 122a to 122c for waiting for respective transmission frames, and the transmission FIFO buffer memory 74 on the LAN controller 61 stores transmission frames from the corresponding areas. Is transferred. Although the structure of the transmission descriptor is slightly different, the basic procedure for transmitting the transmission frame is the same as that described for the case where the transmission descriptor shown in FIG. 10 is used, for example.

[0030]

As described above, as a conventional technique, a mechanism for transmitting a transmission frame by a typical LAN controller used in a network interface device has been described. As described above, the table of the transmission descriptor is entered in the system memory of the host system, and the transmission descriptor is systematically used one after another.
The processing speed of the device driver is increased, and the load on the host system can be reduced.

However, this has a serious problem, which is an inefficient transfer form by copying the contents of the transmission descriptor onto the LAN controller and writing it back. Specifically, for example, in the case of using any type of transmission descriptor among the examples of the two transmission descriptors shown in FIGS. 10 and 12, one transmission frame is transferred to the LAN controller in order to transfer one transmission frame to the LAN controller. The transmission descriptor will be used. That is, each time one transmission frame is processed, the contents of one transmission descriptor must be copied to the multi-purpose register of the LAN controller.

As a copying method, a method using a PCI target write by a device driver may be used, or a PCI master read is generally executed when a LAN controller is required. Also, a PCI bus operation relating to the transmission descriptor is executed separately from the transmission of the transmission frame itself.
Further, after transmitting the transmission frame to the network, it is necessary to write the transmission descriptor back to the system memory of the host system.

By the way, especially in a PCI master read transaction, data preparation on the target side is generally slow, and the transaction often includes many wait cycles or is frequently retried. Therefore, when transmitting transmission frames one after another, the number of times of the PCI bus operation for copying the transmission descriptor can be a large overhead when transferring the transmission frame from the system memory to the LAN controller.
Also, if the size of the transmission frame is small, such overhead becomes even less efficient.

As a specific example, a commercially available NIC is often used in the computing PC cluster system in order to reduce the configuration cost. However, in the computing PC cluster system, generally, short message packets are frequently exchanged. Accordingly, the delay due to the overhead at the time of transmitting the short message packet in the NIC greatly affects the calculation performance of the entire calculation PC cluster system.

Therefore, it is very important how to transmit a short message packet with low latency (delay). Further, even if the transmission speed of the LAN is further improved in the future, the performance of the entire system will be limited by such overhead.

In order to efficiently transfer a transmission frame from the host system to the transmission FIFO buffer memory of the LAN controller, recently, a 64 bit / 66M
It is conceivable to use a PCI bus of 1 Hz. However, in this configuration, the transmission FI of the LAN controller
Although the speed of data transfer to the FO buffer memory is increased, the overhead of reading the transmission descriptor does not disappear.

Also, for example, in Japanese Patent Application Laid-Open No. 6-168196 and US Pat. No. 5,721,955, before all the transmission data is transferred from the host computer to the transmission buffer of the LAN controller, the transmission data to the network is completed. A method for initiating a transmission is disclosed. Although this is a very effective method for improving the transmission performance, there is a danger that an underrun may occur in which the transfer to the transmission buffer becomes empty in time.

For example, see US Pat. No. 5,729,68.
Japanese Patent Laid-Open Publication No. 1 (1999) -121 discloses a method in which a packet fragment array holding transmission packet information is transmitted to a LAN controller as it is, and the LAN controller transfers transmission data to a transmission buffer of the LAN controller based on the information. However, in this method, an extra PCI bus operation occurs to transmit the packet fragment array to the LAN controller, and the overhead increases. This method is disadvantageous in addition to the fact that the CPU power of commonly used PCs is increased and that the method is applied to transmission of relatively short packets, and the circuit is complicated and requires extra memory. Will be.

In any case, the techniques described in these documents do not reduce the overhead due to the unnecessary PCI transaction at the time of transmitting the transmission frame described above. As described above, the conventional network interface device such as a LAN controller has a problem that overhead is generated when a transmission frame is transferred from the system memory of the host system to the network interface device, resulting in poor transfer efficiency.

The present invention has been made to solve such a conventional problem. For example, the transfer efficiency of transmission data can be improved with a simple structure without increasing the circuit scale by mounting a complicated mechanism. It is an object of the present invention to provide a network interface device, a communication device, and the like that can perform such operations.

[0041]

In order to achieve the above object, in a network interface device according to the present invention, a transmission descriptor including control information relating to transmission data and transmission data are input from a communication device as follows. The input transmission data is transmitted to the network based on the input transmission descriptor. That is, the interface unit collectively inputs the transmission descriptor and the transmission data from the communication device, and transmits the input transmission data to the network based on the input transmission descriptor.

Therefore, for example, instead of the transmission data being input from the communication device after the transmission descriptor is input from the communication device and being transmitted to the network as in the related art, the transmission descriptor and the transmission data are collected together. By transmitting the transmission data from the communication device to the network, the transmission speed of the transmission data from the communication device to the network interface device can be increased, thereby transmitting the transmission data to the network at a high speed. can do.

Here, various information may be used as the control information on the transmission data included in the transmission descriptor, for example, information on the size of the transmission data is used. Various data may be used as the transmission descriptor and the transmission data.

As the network, various networks may be used. The data input / output processing performed between the network interface device and the communication device may be performed, for example, by the initiative of the network interface device, or may be performed by, for example, the initiative of the communication device.

Further, for example, after the transfer processing of the transmission descriptor and the transmission data from the communication apparatus to the network interface apparatus is completed, the transmission processing of the transmission data from the network interface apparatus to the network may be performed. The data transmission process may be performed in parallel.

In the network interface device according to the present invention, when the size of the transmission data is smaller than the threshold, the interface means collectively inputs the transmission descriptor and the transmission data from the communication device. Therefore, the transfer speed of the transmission data from the communication device to the network interface device can be increased with respect to the transmission data of a small size, which particularly reduces the transmission speed in the related art, whereby the transmission data is transmitted to the network at high speed. be able to. Whether or not the size of the transmission data is smaller than the threshold is instructed from the communication device to the network interface device, for example.

Here, as the threshold value of the size of the transmission data, various values may be used depending on, for example, the usage status of the system. As a method of determining whether or not the size of the transmission data is smaller than the threshold, in the present invention, for example, in a configuration in which a plurality of sizes can be selected as the size of the transmission data, a predetermined small size is selected. In this case, a method of determining that the size of the transmission data is smaller than the threshold is used.

In one embodiment of the network interface device according to the present invention, the communication device has a transmission descriptor and a data storage area for storing transmission data of a predetermined size or less corresponding to a plurality of transmission data sizes. The interface means inputs data stored in any data storage area of the communication device according to the size of the transmission data from the communication device,
The transmission descriptor and the transmission data stored in the data storage area are input from the communication device.

Therefore, by inputting the data stored in the data storage area corresponding to the size of the transmission data from the communication device in accordance with the size of the transmission data, the transmission descriptor and the transmission data stored in the data storage area are input. Then, the transmission data can be transmitted to the network. The data stored in the data storage area of the communication device includes the transmission descriptor and the transmission data. For example, the data storage area may have an empty area where the transmission descriptor and the transmission data are not stored.

Here, the number of data storage areas of the communication device (that is, the number of a plurality of transmission data sizes in the present invention) may be various numbers. Various sizes may be used as the predetermined size of the transmission data that can be stored in each data storage area.

An example in which two data storage areas are used is specifically shown. That is, for example, a first data storage area capable of storing transmission data of size A or smaller, and a second data storage area capable of storing transmission data of size B (B> A) or smaller. Is prepared in the communication device, and the transmission data of A size or less is set to the first.
The transmission data is stored in the data storage area, and the transmission data is input from the first data storage area in the network interface device, and the transmission data is transmitted to the second data storage area for transmission data larger than A size and smaller than B size. And the network interface device inputs transmission data from the second data storage area.

In the network interface device according to the present invention, the interface means inputs information on the number of transmission data to be transmitted from the communication device,
The number of sets of transmission descriptors and transmission data based on the input information is input from the communication device.

Therefore, the number of transmission data to be transmitted is notified from the communication device in advance, and the set of transmission descriptors and transmission data of the number is input from the communication device, so that data from the communication device to the network interface device is transmitted. Transfer processing can be performed efficiently.

A more specific embodiment of the network interface device according to the present invention will be described below. That is, in the network interface device according to the present invention, as an example of the embodiment, a transmission descriptor storage unit that stores a transmission descriptor, a transmission data storage unit that stores transmission data, a transmission descriptor that is collectively input from a communication device, and Selector means for separating each of the transmission data, storing the separated transmission descriptor in the transmission descriptor storage means, and storing the separated transmission data in the transmission data storage means, wherein the interface means is stored in the transmission descriptor storage means. The transmission data stored in the transmission data storage is transmitted to the network based on the transmission descriptor.

Further, the network interface device according to the present invention includes, as one embodiment, transmission status information holding means for holding information on the transmission status of transmission data to the network, and the transmission status notifying means includes the transmission status information holding means. The transmission status of the transmission data is notified to the communication device based on the held information of the communication device.

In one embodiment of the network interface device according to the present invention, the information on the transmission status includes information indicating that the transmission process of the transmission data has been completed and whether or not the transmission process has succeeded. Information is included. The information indicating that the transmission process of the transmission data has been completed is notified to the communication device when the transmission process ends, for example, and the information indicating whether or not the transmission process has succeeded is, for example, the communication device. Is notified to the communication device in response to a request from the communication device.

In the network interface device according to the present invention, as one embodiment, the information relating to the transmission status includes information for specifying transmission data for which transmission processing has failed. Then, information specifying the transmission data for which the transmission processing has failed is notified to the communication device in response to a request from the communication device, for example.

Further, the present invention provides a communication device capable of realizing the data transfer as described above.
That is, in the communication device according to the present invention, when outputting the transmission descriptor and the transmission data to the network interface device that transmits the transmission data to the network based on the transmission descriptor including the control information about the transmission data, , The transmission descriptor and the transmission data are output together to the network interface device.

In the communication device according to the present invention, when the size of the transmission data is smaller than the threshold, the communication means outputs the transmission descriptor and the transmission data to the network interface device together.

Further, the communication device according to the present invention has a transmission descriptor and a data storage area for storing transmission data of a predetermined size or less corresponding to a plurality of transmission data sizes. The data stored in any of the data storage areas is output to the network interface device according to the size.

In the communication device according to the present invention, the communication means outputs information on the number of transmission data to be transmitted to the network interface device, and transmits the set of transmission descriptors and transmission data of the number to the network interface device. Output to the device.

Further, the present invention provides a storage medium storing a program capable of realizing the data transfer as described above. That is, in the storage medium according to the present invention, a program to be executed by a computer is stored in a readable manner by an input means of the computer, and the program transmits transmission data to a network based on a transmission descriptor including control information on the transmission data. And causes the computer to execute a process of collectively outputting the transmission descriptor and transmission data to the network interface device transmitting the transmission descriptor.

Further, in the storage medium according to the present invention, when the size of the transmission data is smaller than the threshold value, the program causes the computer to perform a process of outputting the transmission descriptor and the transmission data to the network interface device together. Let it run.

Further, in the storage medium according to the present invention, the program is provided in a data storage area provided corresponding to a plurality of transmission data sizes and storing a transmission descriptor and transmission data of a predetermined size or less. And causing the computer to execute a process of outputting data stored in any of the data storage areas to the network interface device according to the size of the data.

In the storage medium according to the present invention, the program includes a process of outputting information on the number of transmission data to be transmitted to the network interface device, and a set of the transmission descriptor and the transmission data of the number. And causing the computer to execute a process of outputting to the network interface device. In the present invention, it is also possible to provide a program for executing the above-described processing.

[0066]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to the drawings. In the embodiment described below, the device driver of the host system checks the size of the transmission frame, and if the size of the transmission frame is determined to be smaller than a certain value, the transmission descriptor and the transmission data are transmitted at once. By performing burst transfer and reading by the LAN controller, the transmission frame is transmitted from the host system to the L
Eliminating the overhead due to the occurrence of extra transactions when transferring to the AN controller.

An embodiment in which the network interface device according to the present invention is applied to a LAN controller and the communication device according to the present invention is applied to a host system will be described below with reference to the drawings.

First, a data transfer system according to a first embodiment of the present invention will be described. FIG. 1 shows a LAN controller 1 as an example of a data transfer system to which the present invention is applied.
And a host system 2 connected to the LAN controller 1 and a network 3 connected to the LAN controller 1.

The LAN controller 1 includes a peripheral component interconnect (PCI) bus interface 11 having an interface function with the host system 2, a DMA controller 12 for controlling access to a memory, and
A first multi-purpose register 13 and a second multi-purpose register 14 for storing data, a first-in-first-out (FIFO) buffer memory 15 for storing data for transmission, and a storage for dynamically switching between a transmission descriptor and a storage destination for transmission data. A selector 16 which is a branching logic, and a media access control (MA) for controlling media access.
C) an SIA interface 18 having an interface function between the controller 17 and the network 3;
M having an interface function with the network 3
An II interface 19, a reception FIFO buffer memory 20 for storing reception data, and a data control unit 21 for controlling these processing units 11 to 20 are provided.

The host system 2 is provided with a CPU 22 for executing various processes and a system memory 23 for storing data. The SIA interface 18 and the MII interface 19 provided in the LAN controller 1 are connected to the network 3,
The PCI bus interface 11 is connected to a CPU 22 and a system memory 23 provided in the host system 2.

Here, the operation performed by the data transfer system of the present embodiment is such that the transmission data is transferred from the host system 2 to the LAN controller 1 and the transmission data is transmitted to the LAN controller 1.
Except for the operation related to the process of transmitting data from the controller 1 to the network, the operation is the same as the operation performed by the system shown in FIG. 9, for example.

First, an example of a preparation operation performed by the device driver of the host system 2 to transfer a transmission frame from the system memory 23 of the host system 2 to the LAN controller 1 will be described. Note that the device driver is generally software for enabling use of a peripheral device connected to the computer. In this example, the CPU 22 of the host system 2 executes the device driver program stored in the system memory 23. Thus, the operation processing by the device driver is performed.

That is, first, when the LAN controller 1 is started, the device driver performs configuration as a PCI device, and sets a command, a latency timer, and a base address. Then, the device driver maps the first multi-purpose register 13 of the LAN controller 1 to the system memory 23. By performing such a mapping, the first multi-purpose register 1
3 can be accessed from both the host system 2 and the LAN controller 1.

Here, as the first multi-purpose register 13, a register generally called CSR is used. FIG. 2A shows a configuration example of the first multi-purpose register 13. The first multi-purpose register 13 includes a command field 31 for storing command (Command) information and a status (Status). It is composed of a status field 32 for storing information and a VP (Various Purpose) register field 33 which is a register (Register) for storing information for various purposes.

The command field 31 is used as an area in which a command for the LAN controller 1 is set. The status field 32 is used as an area in which bits indicating the internal state of the LAN controller 1 and the like are set. VP register field 33
Is 32b to be accessed by the LAN controller 1.
It is used as an area for setting the address of the it and the like.

FIG. 11B shows an example of the configuration of a command field 31. The command field 31 includes a command (CMD) bit 34 indicating the content of the command, and a command A serial number (SerialNumber) bit 35 indicating the number is included. FIG. 3C shows an example of the configuration of the status field 32. The status field 32 includes an error status (Error Status) bit 36 indicating the content related to the error, and a packet of a continuously transmitted packet. A serial packet number (Serial Packets Number) bit 37 indicating the number and a failer packet indicator bit 38 indicating a packet whose transmission has failed are included. A detailed description of the configuration shown in FIGS. 7B and 7C will be given in a second embodiment described later.

Next, the device driver of the host system 2 sends an area for storing the transmission descriptor (transmission descriptor storage area) in the system memory 23 and an area of the buffer memory for transmission frame standby (transmission (Standby buffer). In addition,
In this example, the transmission descriptor has a chain structure, and prepares an area for two channels.

FIG. 3 shows an example of a transmission descriptor storage area for two channels and a transmission standby buffer secured in the system memory 23. Specifically, FIG. 2 shows a Ch1 data storage area 41 that is an area for storing data of channel 1 (Ch1), and a channel 2 (Ch1).
2 shows a Ch2 data storage area 42 which is an area for storing data.

The Ch1 data storage area 41 includes a plurality of sets each having a fixed-size transmission descriptor storage area and a corresponding fixed-size transmission standby buffer arranged at consecutive address positions. The "0" -th transmission descriptor storage area 43a, the "0" -th transmission standby buffer 44a, the "1" -th transmission descriptor storage area 43b, and the "1" -th transmission descriptor storage area 43a. Buffer 4 for sending data
4b, “2” -th transmission descriptor storage area 43
The respective areas are arranged at consecutive address positions in the order of c, the "2" -th transmission standby buffer 44c,.... In the channel 1 of this example, a size of 3000 bytes is used as the fixed size of the transmission standby buffer.

Similarly, the Ch2 data storage area 42 stores 1
A set in which two fixed-size transmission descriptor storage areas and one corresponding fixed-size transmission standby buffer are arranged at consecutive address positions is arranged at a plurality of consecutive address positions. “0” -th transmission descriptor storage area 45a, “0” -th transmission standby buffer 46a, “1” -th transmission descriptor storage area 45b, “1” -th transmission standby buffer 46b, “2” -th transmission Descriptor storage area 45
The respective areas are arranged at consecutive address positions in the order of c, the “second” transmission standby buffer 46c,... In the channel 2 of this example, a size of 100 bytes is used as the fixed size of the transmission standby buffer.

As described above, in the present embodiment, two channels, that is, channel 1 having 3000 bytes and channel 2 having 100 bytes are secured as memory areas of the transmission frame waiting buffer. The transmission descriptor chain may be prepared for, for example, one channel. However, as shown in this example, a channel having a small transmission frame standby buffer area for a small transmission frame (that is, channel 2) is separately provided. It is preferable to prepare one channel because it is possible to prevent waste of the system memory 23.

As described above, the data storage areas 41 and 42 required by the device driver are stored in the host system 2.
When a higher-level system such as a PC requests data transmission, the device driver checks the size of transmission data to be transmitted to the network 3 and the size is larger than 100 bytes. In this case, control is performed so that transmission processing of transmission data is performed using the transmission descriptor chain of channel 1, while if the size is 100 bytes or less, transmission is performed using the transmission descriptor chain of channel 2. Control is performed so that data transmission processing is executed.

Next, the transmission frame stored in the system memory 23 of the host system 2 is stored in the host system 2.
An example of the operation of transferring from the LAN controller 1 to the LAN controller 1 will be described. In FIG. 4, the transmission frame is stored in the host system 2.
2 shows an example of a procedure of a process of transferring data from the LAN controller 1 to the LAN controller 1, and an operation example of the process will be described with reference to FIG.

That is, first, as described above, the preparation by the device driver is completed, and when a transmission command is instructed to the device driver from the upper software (step S1), the device driver includes the transmission data to be transmitted. The size of the transmission frame to be transmitted is confirmed (step S2).

As a result of this check, if the size of the transmission frame is larger than a certain size (100 bytes in this example), for example, the transfer processing sequence described with reference to the system shown in FIG. Transmission processing of a transmission frame is performed according to a transfer sequence (hereinafter, referred to as a normal sequence) (step S8).

That is, in this normal sequence, first,
The device driver stores the data storage area 41 of channel 1
Each of the transmission descriptor storage areas 43a, 43b,.
Are set, and the transmission frames to be transmitted are stored in the transmission waiting buffers 44a, 44b,... In the data storage area 41.

Next, the device driver sets the start address of the first (“0th” in this example) transmission descriptor storage area 43 a of channel 1 to the LAN controller 1.
Of the first multi-purpose register 13 in the VP register field 33, and following this processing, a transmission command (TX CMD: Transmit Commit
mand) by writing the bit value corresponding to
A transmission data transmission command is issued to the controller 1. Note that these processes are realized by a PCI target write cycle.

Then, the LAN controller 1 calculates the address from the address transmitted from the host system 2 and stored in the VP register field in the first multi-purpose register 13.
Each transmission descriptor storage area 43a, 43 of channel 1 prepared in the system memory 23 of the host system
Read the transmission descriptor stored in b,... and store it in the second multi-purpose register 14. In this case,
The selector 16 switches so that the transmission descriptor from the host system 2 is stored in the second multi-purpose register 14.

Here, the LAN controller 1 can know the size of the transmission frame based on the information content of the transmission descriptor stored in the second multi-purpose register 14. Next, the LAN controller 1 renews the PCI master. A read transaction request is issued, and the transmission frame stored in each transmission standby buffer 41 of the channel 1 prepared in the system memory 23 of the host system 2 is read-transferred from the host system 2 to the LAN controller 1. Then, the transmission frame read by the LAN controller 1 is stored in the transmission FIFO buffer memory 15, whereby the transfer processing is completed (step S7). In this case, the selector 1
6 indicates that the transmission frame from the host system 2 is the transmission F
Switching is performed so as to be stored in the IFO buffer memory 15.

On the other hand, the result of the above confirmation (step S
2) If the size of the transmission frame is smaller than a certain size (100 bytes in this example), the device driver stores the transmission descriptor storage areas 45a, 45b,. A necessary value is set, and a transmission frame to be transmitted is stored in each transmission standby buffer 46a, 46b,... In the data storage area 42 (step S3).

Thereafter, the device driver operates on channel 2
Is written to the VP register field 33 in the first multi-purpose register 13 of the LAN controller 1 at the beginning (in this example, the "0th") transmission descriptor storage area 45a. A small transmission command (S-TXC
By writing a bit value corresponding to the MD (Small-Transmit Command), a transmission command for transmission data of a relatively small size is generated for the LAN controller 1 (step S4). This process is performed by the device driver making a PCI target write access to the command field 31 with a value corresponding to S-TX CMD.

At this point, the LAN controller 1 does not yet know the contents set in the transmission descriptor stored in the host system 2 and thus does not know the size of the frame to be actually transmitted. Whenever a transmission command is issued, in addition to each transmission descriptor, each transmission standby buffer 46a,
The data of 100 bytes in 46b,... Is subjected to PCI burst transfer from the host system 2 to the LAN controller 1, and the transmission frame is stored in the transmission FIFO buffer memory 15 (step S5).

That is, in this transfer sequence, the transmission descriptor and the transmission frame of the channel 2 stored in the system memory 23 of the host system 2 are collectively set to L.
The LAN controller 1 inputs the transmission descriptor to the selector 16.
Are stored in the second multi-purpose register 14, and the input transmission frame is separated by the selector 16 and stored in the transmission FIFO buffer memory 15.

When the transmission processing of the transmission frame is executed as described above, the LAN controller 1 determines whether the transmission processing is normally performed in the status field of each transmission descriptor stored in the second multi-purpose register 14. The status field is updated by writing a value indicating the status (step S6), whereby the transfer process is completed (step S7).

Next, based on the transmission descriptor stored in the second multi-purpose register 14 of the LAN controller 1, the transmission frame stored in the transmission FIFO buffer memory 15 of the LAN controller 1 is transferred to the network 3.
An example of the operation of transmitting to the. In FIG. 5,
For example, after a transmission descriptor or a transmission frame is stored in the LAN controller 1, the transmission frame is
An example of a procedure of a process of transmitting data from the N controller 1 to the network 3 is shown, and an operation example of the process is shown with reference to FIG.

That is, in the LAN controller 1, for example, after the transmission data is transferred to the transmission FIFO buffer memory 15 (step S11), the completion of the transfer processing is notified to the MAC controller 17. Then, the MAC controller 17 refers to the transmission descriptor stored in the second multi-purpose register 14 to determine the size of the transmission frame (Step S12).

Here, for example, when the transfer processing of the channel 2 is performed, the transmission FIFO buffer memory 15 may contain unnecessary data other than the data to be actually transmitted. Reference numeral 17 denotes a transmission FIFO buffer memory 1 which stores data of the size of the transmission frame exactly by referring to the transmission descriptor.
5 from the SIA interface 18 or M
The data is transmitted to the network 3 via the II interface 19 (step S13).

When the transmission processing of the transmission data to the network 3 is completed in this way, the MAC controller 17 informs the data control section 21 of the success or failure of the transmission, and the data control section 21 receiving the notification notifies the data control section 21 of the first transmission. Multipurpose register 1
A value is set to an error status bit 36 in the status field 32 of No. 3 (step S14). Here, as the value of the error status bit 36, for example, a value of “01” is set when the transmission processing is successful, and a value of “11” is set when the transmission processing is failed.

Further, in this example, the area for storing the data of the lower 1 bit of the error status bit 36 is directly connected to the interrupt line of the PCI, so that the device driver of the host system 2 completes the transmission processing, for example. As a result, the completion of the transmission process can be grasped by the occurrence of the interrupt, and the value of the error status bit 36 in the first multi-purpose register 13 of the LAN controller 1 can be read to determine the success of the transmission process. (Step S
15).

If the device driver does not need to know whether or not the transmission has succeeded, the device driver does not need to read the value of the error status bit 36 in the multi-purpose register 13 of the LAN controller 1. After receiving the signal indicating the end of the transmission processing via the interrupt line, the driver need only clean the transmission descriptor to make it reusable.
For example, in the prior art, the error status is always described in the transmission descriptor and written back from the LAN controller 1 to the host system 2 irrespective of whether it is necessary to know whether the transmission is successful or not. , If you do n’t need to know if the transmission was successful,
It is possible to omit the transaction for this.

As described above, in the data transfer system using the data transfer method as in this example, for example, the channel 2
In the transfer processing of the transmission frame using the transmission frame, the transmission frame can be transferred from the system memory 23 of the host system 2 to the LAN controller 1 without generating the overhead related to the transmission of the transmission descriptor. Efficient transfer becomes possible. Further, in this example, it is possible to omit the PCI transaction related to the writing back of the transmission descriptor.

In this example, when transmitting a transmission frame having a relatively small size (in this example, a size of 100 bytes or less), a transmission descriptor channel having a small transmission standby buffer (in this example, Since the data transfer is performed using the channel 2), for example, the use efficiency of the system memory 23 does not deteriorate.

Also, in this example, if a transmission frame of a relatively small size is stored in the data storage area 41 of the channel 1, for example, the free area may increase, so that a predetermined size (in this example, 100 bytes) is used. ) The following small transmission frames are stored in the data storage area 42 of the channel 2 so that the generated free area is reduced. Also, the data storage area 4 of channel 1
In the data transfer process of channel 1, since a transmission descriptor is transferred from the host system 2 to the LAN controller 1 in the data transfer process of the channel 1, a necessary amount of data based on the transmission descriptor may be generated. Transmission frame from host system 2 to LAN
It has been transferred to the controller 1.

Next, as a second embodiment of the present invention, FIG.
An example of an operation performed by the data transfer system using the command field 31 shown in (b) and the status field 32 shown in FIG. Note that the configuration of the data transfer system of the present embodiment is, for example, as shown in FIG.
The description is omitted because it is the same as that shown in FIG.

That is, in the data transfer system as shown in FIG. 1, for example, when a long message packet is being transmitted, transmission of a plurality of short message packets may accumulate in a transmission waiting queue. In such a case, it is possible to more efficiently transmit a short message packet. Here, in this example, the transmission frame is transmitted as a packet to the network 3, and the long data packet indicates a transmission frame stored in the transmission standby buffers 44a, 44b,... Of the channel 1 shown in FIG. ,
The short message packet indicates a transmission frame stored in the transmission standby buffers 46a, 46b,... Of the channel 2 shown in FIG.

In the following, an example of the operation performed by the data transfer system of this embodiment will be described, taking as an example a case where three short message packets of less than 100 bytes are accumulated. In such a case, in this example, as shown in FIG. 2B, the command field 31 in the first multi-purpose register 13 of the LAN controller 1 has a serial number bit indicating the number of packets to be transmitted at one time. An area for storing 35 is provided. And the device driver
When transferring the three short message packets stored in the queue to the LAN controller 1, the S-TX CMD is written into the CMD bit 34 provided in the command field 31 in the first multi-purpose register 13 and at the same time the three short message packets are stored. The number of the transmission queue (3 in this example) is written to the serial number bit 35.

Then, in the LAN controller 1, the data control unit 21 refers to the value of the serial number bit 35 in the first multi-purpose register 13, and based on this value,
3 transmit descriptors for channel 2 and 1
A set of 00-byte data is burst-transferred and read from the host system 2 to the LAN controller 1 at a time.

Here, as shown in FIG. 6, for example, in the LAN controller 1 of this embodiment, the transmission descriptor 4
5a, 45b,... And transmission standby buffers 46a, 46
b,..., the host system 2
, The selector 16 dynamically separates the transmission descriptors 45a, 45b,... And the transmission data, and separates and stores the respective storage destinations in the second multi-purpose register 14 and the transmission FIFO buffer memory 15. I do. By doing so, for example, six PCI transactions have occurred in the conventional data transfer method, whereas in the data transfer method of the present example, one PCI transaction has occurred.
Only one PCI transaction is required, and the overhead can be greatly reduced.

In this example, as another characteristic configuration, as shown in FIG. 2C, the status field 32 in the first multi-purpose register 13 stores the short message packet of the continuously transmitted short message packet. A serial packet number bit 37 for setting the number and a failer packet indicator bit 38 for specifying a packet in which an error has occurred in transmission are provided, so that which packet has an error in network transmission has been determined.
The data can be transmitted from the AN controller 1 to the device driver of the host system 2.

For example, when an error occurs in the packet transmitted second or the like, the transmission processing is performed as a whole by using the value of the error status bit 36 in the status field 32 as described in the first embodiment. Just indicating whether the packet has succeeded or failed cannot identify which packet caused the error by the device driver of the host system 2. Therefore, in this example, the number of packets transmitted together is set in the serial number packet bit 37, and the bit corresponding to the packet in which the error has occurred is set in the failure packet indicator bit 38.

Here, FIG. 7 shows an example in which the value of the failure packet indicator bit 38 in the status field 32 is changed. FIG. 7A shows an example of a bit string in the status field 32 when an error occurs in the transmission processing of the second packet among the three packets when three packets are continuously transmitted together. Is shown. In this case, the value of the error status bit 36 becomes "10", the value of the serial packet number bit 37 becomes "011", and the value of the failure packet indicator bit 38 becomes "0000010". It indicates that an error has occurred in the second packet.

The device driver of the host system 2 operates in the first multi-purpose register 1 of the LAN controller 1.
After checking the bit string of the status field 32 in 3, all the bit values in the status field 32 are reset to “0”. Here, FIG. 4C shows an example of a bit string in the reset status field 32, and all the values are set to “0”.

FIG. 13B shows that the next packet transmission is performed before the device driver of the host system 2 checks the bit string in the status field 32 in the state shown in FIG. 4 shows an example of a bit string in the status field 32 in the case where the error occurs.
In this case, the value of the error status bit 36 is “10”
The value of the serial packet number bit 37 is added and set by the number of the next transmitted packet to be set to “110”, and the value of the failure packet indicator bit 38 is OR-operated by the number of the transmitted packet. "0010010" indicates that six packets have been transmitted and an error has occurred in the second and fifth packets.

As described above, when the device driver of the host system 2 checks the bit string of the status field 32 in the first multi-purpose register 13 of the LAN controller 1, all the bit values in the status field 32 become "0". And the bit string in the status field 32 becomes the state shown in FIG.

As described above, in this example, the host system 2
By reading the first multi-purpose register (CSR) 13 of the LAN controller 1 by the device driver of the LAN controller 1, the transmission message packet in which the error has occurred can be specified.
(Ission Control Protocol / Internet Protocol) layer-level delay can be minimized. As described in the first embodiment, for example, when it is not necessary to obtain the error information by the device driver, the device driver sets the first multi-purpose register (CSR).
It is possible to omit the transaction that leads to 13.

Next, FIG. 8A shows an example of a transfer sequence of a transmission frame when a conventional data transfer system or data transfer method is used, while FIG. FIG. 3 shows an example of a transfer sequence of a transmission frame when a data transfer system and a data transfer method to which the present invention is applied, and FIG. 10A and FIG. 10B show data to which the present invention is applied. The effects obtained by the transfer system and the like are quantitatively shown.

Note that, during the transfer sequence shown in FIGS. 9A and 9B, a clock signal (CLK), a bus use request signal (REQ #), and a bus use permission signal (GN
T #), a transmission frame signal (FRAME #), an initiator ready signal (IRDY #), a device select signal (DEVSEL #), and a target ready signal (TRDY #).

That is, conventionally, as shown in FIG. 11A, after the transmission descriptor is transferred from the host system 2 to the LAN controller 1 by the transaction 51 related to the PCI read transfer processing of the transmission descriptor, the PCI of the transmission frame is transmitted. Since the transmission frame was read-transferred from the host system 2 to the LAN controller 1 by the transaction 53 relating to the read transfer processing, these two transactions 5
Transaction 5 by another device during 1, 53
2 could be performed, and the frame transfer took a very long time.

On the other hand, in a transfer process using, for example, channel 2 in a data transfer system or the like to which the present invention is applied,
As shown in FIG. 6B, a transaction 54 is performed to collectively transmit transmission data of a predetermined size in addition to the transmission descriptor, and to perform a burst transfer from the host system 2 to the LAN controller 1. 1. The time until the data is transferred within 1 is short, and transmission can be performed with low latency.

Further, in the examples shown in FIGS. 11A and 11B, the case where the present invention is applied is larger than that of the conventional example.
Although it has an advantage of about 25 clocks (CLK), in actuality, in a conventional data transfer system or the like, data preparation is slow and retry may be repeated. Expected. In other words, when a network having a transmission rate of 1 Gbps is used, in a data transfer system or the like to which the present invention is applied, it is possible to save time for sufficiently transmitting a message packet of about 100 bytes. Further, as shown in the second embodiment, when a plurality of message data packets are collectively transferred from the host system 2 to the LAN controller 1, the effect obtained by the transfer processing according to the present invention is further enhanced. .

As described above, in the data transfer system and the data transfer method to which the present invention is applied, the overhead at the time of transmitting the transmission data can be greatly reduced as compared with, for example, the conventional data transfer system and the data transfer method. Thus, transmission data can be transferred from the system memory of the host system to the LAN controller at high speed.

As described above, according to the data transfer apparatus and the data transfer method according to the embodiment of the present invention, for example, in a configuration using a network interface device for connecting a computer system to a network, the host system transmits the data to the network. When transferring transmission data onto the interface device, the software of the device driver divides the packet into at least two categories according to the size of the packet to be transmitted, and if it determines that the size of the packet to be transmitted is small, the S-TX CM (not at the time of normal transmission)
D to the network interface device. When this command is issued, in addition to the transmission descriptor, uniform transmission data of a certain predetermined size is burst-transferred from the host system by one PCI bus operation and buffered in the network interface device.

In the data transfer system and the data transfer method according to the embodiment of the present invention, when performing the above-described transfer processing, the device driver controls / writes the bit value corresponding to the S-TX CMD. A status register (CSR) is used, and a selector is used to dynamically switch a storage destination memory between a transmission descriptor and transmission data.

Further, as described above, the data transfer system and the data transfer method according to the embodiment of the present invention are provided with at least two transmission descriptor channels having different sizes of data waiting areas for holding transmission data. The transmission process of the transmission data is executed by appropriately switching the channel of the transmission data.

In the data transfer system and the data transfer method according to the embodiment of the present invention, the CSR comprises a bit indicating that the transmission processing to the network has been completed and a bit indicating whether the transmission processing has succeeded. A bit indicating that the transmission process has been completed is directly connected to the interrupt signal line and notified to the host system as an interrupt signal, and the device driver software checks whether the transmission process was successful. By reading the CSR only when it is necessary to know whether or not the transmission process is successful, it is confirmed whether or not the transmission process is successful.

In the data transfer system and the data transfer method according to the embodiment of the present invention, the CSR designates a serial number field for designating the number of frames to be processed continuously when the command of the transmission command is S-TX CMD. The network interface device checks the value of the serial number field, and collectively transmits a set of transmission descriptors and transmission data for the number of frames described in the serial number field and performs burst transfer from the host system. Put in.

In the data transfer system and the data transfer method according to the embodiment of the present invention, the CSR specifies the serial packet number field indicating the number of frames that have been actually transmitted and processed, and specifies the frame for which transmission processing has failed. And a failure packet indicator field for performing the transmission, and the device driver software needs to know whether or not the transmission process has succeeded.
By reading R, a frame in which an error has occurred can be specified.

In the embodiment described above, various processes according to the present invention are realized by using a form in which a device driver is installed in a hard disk drive (HDD) of the host system 2 or the like. The device driver corresponds to the program according to the present invention, and the HDD or the like in which the device driver is installed corresponds to the storage medium according to the present invention. In the embodiment described above, the device driver performs all kinds of processing for driving the hardware, and various kinds of processing performed by the program according to the present invention are implemented as a part of the processing performed by the device driver. Have been.

Here, the configurations of the network interface device and the communication device according to the present invention are not necessarily limited to those described above, and various configurations may be used. Further, the application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.

As an example, in the present embodiment, the case where the network interface device according to the present invention is applied to a LAN controller has been described. However, the present invention can be applied to various network interface devices. Similarly, in the present embodiment, the case where the communication device according to the present invention is applied to a personal computer (host system) has been described, but the present invention can be applied to various communication devices.

The various processes performed by the network interface device and the communication device according to the present invention include, for example, a processor executing a control program stored in a ROM in a hardware resource including a processor and a memory. A configuration to be controlled may be used, and for example, each functional unit for executing the processing may be configured as an independent hardware circuit. The present invention can also be understood as a computer-readable storage medium such as a floppy (registered trademark) disk or a CD-ROM storing the above-mentioned control program or the program (the program itself). By inputting the information to a computer and causing the processor to execute the processing, the processing according to the present invention can be performed.

[0132]

As described above, according to the network interface device, the communication device, and the storage medium according to the present invention, the transmission descriptor including the control information on the transmission data and the transmission data are collectively input from the communication device to the network interface device. Then, since the transmission data input based on the transmission descriptor input by the network interface device is transmitted to the network, the transfer speed of the transmission data from the communication device to the network interface device can be increased. , Transmission data can be transmitted to the network at high speed.

Further, according to the network interface device or the like according to the present invention, when the size of the transmission data is smaller than the threshold, the transmission descriptor and the transmission data are collectively input from the communication device to the network interface device. In particular, the transmission speed of the transmission data from the communication device to the network interface device can be increased with respect to the transmission data of a small size that causes the transfer speed to be slow.

Further, according to the network interface device or the like according to the present invention, the communication device has a transmission descriptor and a data storage area for storing transmission data of a predetermined size or less corresponding to a plurality of transmission data sizes. Because data stored in any data storage area of the communication device according to the size is input from the communication device to the network interface device,
For example, data transfer processing from a communication device to a network interface device and transmission data transmission processing to a network can be performed using a data storage area suitable for the size of transmission data among a plurality of prepared data storage areas. .

According to the network interface device of the present invention, information on the number of transmission data to be transmitted is input from the communication device to the network interface device, and the number of transmission descriptors and transmission data based on the input information is input. Is input from the communication device to the network interface device, so that data transfer processing from the communication device to the network interface device can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a data transfer system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a first multi-purpose register.

FIG. 3 is a diagram illustrating an example of a transmission descriptor storage area for two channels and a transmission standby buffer;

FIG. 4 is a flowchart illustrating an example of a procedure of a process of transferring a transmission frame from a host system to a LAN controller.

FIG. 5 is a flowchart illustrating an example of a procedure of a process of transmitting a transmission frame from a LAN controller to a network.

FIG. 6 is a diagram illustrating a process of switching a data storage destination by a selector.

FIG. 7 is a diagram illustrating an example of a state in which a value such as a failure packet indicator bit in a status field is changed.

FIG. 8 is a diagram illustrating an example of an effect obtained by a data transfer system or the like to which the present invention is applied.

FIG. 9 is a diagram showing a configuration example of a conventional typical Ethernet LAN controller.

FIG. 10 is a diagram illustrating an example of the structure of a transmission descriptor.

FIG. 11 is a diagram illustrating an example of a ring structure of a transmission descriptor.

FIG. 12 is a diagram illustrating another example of the structure of the transmission descriptor.

FIG. 13 is a diagram illustrating an example of a chain structure of a transmission descriptor.

[Explanation of symbols]

1. LAN controller, 2. Host system,
3. Network, 11. PCI bus interface, 12. DMA controller, 13, 14,.
Multi-purpose register, 15 ··· FIFO buffer memory for transmission, 16 · selector, 17 · · MAC controller, 18 · · SIA interface, 19 · · MII
Interface, 20 FIFO buffer memory for reception, 21 data control unit, 22 CPU, 23
..System memory, 31..Command field,
32 status field, 33 VP register field, 34 command bit, 35 serial number bit, 36 error status bit, 37 serial packet number bit, 38
・ Failer packet indicator bits, 41, 42
..Data storage areas, 43a to 43c and 45a to 45c
..Transmission descriptors, 44a to 44c, 46a to 4
6c buffer for transmission,

Claims (12)

[Claims] 1. A transmission descriptor including control information on transmission data and transmission data are input from a communication device,
In a network interface device for transmitting transmission data input based on an input transmission descriptor to a network, the transmission descriptor and the transmission data are collectively input from a communication device, and the transmission data input based on the input transmission descriptor is transmitted to a network. A network interface device comprising interface means for transmitting data to a network. 2. The network interface device according to claim 1, wherein the interface unit collectively inputs the transmission descriptor and the transmission data from the communication device when the size of the transmission data is smaller than a threshold value. Interface device. 3. The network interface device according to claim 1, wherein the communication device has a transmission descriptor and a data storage area for storing transmission data of a predetermined size or less corresponding to a plurality of transmission data sizes. Wherein the interface means inputs data stored in any of the data storage areas of the communication device according to the size of the transmission data from the communication device. 4. The network interface device according to claim 1, wherein the interface unit inputs information on the number of transmission data to be transmitted from the communication device, and the input information includes A network interface device for inputting a set of transmission descriptors and transmission data based on the number of transmission descriptors from a communication device. 5. A communication device for outputting a transmission descriptor and transmission data to a network interface device for transmitting transmission data to a network based on a transmission descriptor including control information relating to the transmission data, the communication device comprising: A communication device comprising communication means for outputting to a network interface device collectively. 6. The communication device according to claim 5, wherein the communication unit collectively outputs the transmission descriptor and the transmission data to the network interface device when the size of the transmission data is smaller than the threshold value. Communication device. 7. The communication device according to claim 5, further comprising a transmission descriptor and a data storage area for storing transmission data of a predetermined size or less corresponding to a plurality of transmission data sizes. A communication device for outputting data stored in one of data storage areas to a network interface device according to a size of transmission data. 8. The communication device according to claim 5, wherein the communication unit outputs information on the number of transmission data to be transmitted to the network interface device,
A communication device for outputting a set of transmission descriptors and transmission data of the number to a network interface device. 9. A storage medium storing a program to be executed by a computer in a manner readable by an input means of the computer, wherein the program transmits transmission data to a network based on a transmission descriptor including control information on the transmission data. A storage medium for causing a computer to execute a process of collectively outputting a transmission descriptor and transmission data to a network interface device to be executed. 10. The computer-readable storage medium according to claim 9, wherein the program performs a process of collectively outputting a transmission descriptor and transmission data to a network interface device when the size of the transmission data is smaller than a threshold value. A storage medium characterized by being executed by a user. 11. The storage medium according to claim 9, wherein the program is provided in correspondence with a plurality of transmission data sizes, and stores a transmission descriptor and transmission data of a predetermined size or less. A storage medium for causing the computer to execute a process of outputting data stored in any one of the data storage areas to the network interface device according to the size of transmission data. 12. The method according to claim 9, wherein
The storage medium according to claim, wherein the program outputs, to the network interface device, a process of outputting information regarding the number of transmission data items to be transmitted to the network interface device, And causing the computer to execute a process of outputting the data.