JPH07334411A - Storage area management method - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a storage area management method in which the area is not wasted by simple processing and a data buffer using the storage area management method. A data buffer for storing a plurality of data, a unit length storage means for storing a plurality of different unit lengths, and a data length storage for storing a unit length corresponding to each of the plurality of data stored in the data storage means. Provide means. According to the present invention, it is possible to realize storage area management that is simple in processing and has little waste of area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data storage area management system in a storage device such as a semiconductor memory, and more particularly to a packet buffer management system in a communication device.

[0002]

2. Description of the Related Art Conventionally, two methods are known as a method of managing an area for storing data in buffer management of a communication device connected to a network. The first method is a method of allocating an area corresponding to the maximum value of the data length to each data regardless of the length of the stored data, and the second method is an area of a relatively small fixed length. This is a method of linking with a pointer and allocating an amount of area required for data storage for each data. (For example, ″ Intern
etworking with TCP / IP volume2 ″, P32-33, 1991, P
rentice hall).

[0003]

Of the above-mentioned conventional management methods, the first method uses data that is extremely shorter than the maximum data length, for example, 64 bytes for a maximum length of 4 kilobytes.
There is a problem that most of the storage area is wasted when storing bytes of data. In the second method, if the length of the area is reduced (for example, to 128 bytes),
Although the waste of the area is reduced, there is a disadvantage that it is necessary to record the number of used areas of each data and calculate the pointer update amount by updating the buffer management pointer.

An object of the present invention is to provide a storage area management system that reduces the processing for storage area management and reduces waste of the area.

[0005]

[Means for Solving the Problems] For storage area management,
A data length having a high probability is set as a unit length, and an area having the shortest unit length capable of storing data among a plurality of unit lengths is assigned to each data stored in the data storage means,
The unit length of the area assigned to each data is recorded.

[0006]

According to the present invention, when storing data having a length close to any one of a plurality of preset unit lengths, the waste of the area is reduced, so that the unit length is determined based on the probability distribution of the data length. If set, the probability of waste can be reduced.

Further, in updating the pointer, the update amount is calculated every time only by discriminating which of a plurality of unit lengths the area used for data storage is from the data length storage means and adding the unit length to the pointer. Processing is easy because it is not necessary.

[0008]

EXAMPLES Next, examples of the present invention will be described. The inter-network connection device 200 shown in FIG.
The storage area management system according to the present invention is used for the 00 reception packet buffer.

The reception processing unit 100 shown in FIG. 1 is a processor 110 for processing a packet, a data storage means 700 implemented by a semiconductor memory, and data for writing a packet received from the network interface 220 into the data storage means 700. The processed packet in the writing unit 300 and the data storage unit 700 is processed by the processor 1.
The data reading means 500 transfers the data to the transmission processing unit 210 in accordance with the instruction of 10.

In the reception processing section 100, the data storage means 70
The data storage area 710 in 0 is managed as a circular buffer. The packet received from the network interface 220 is stored in the data storage area 700 by the data writing unit 300, processed by the processor 110, and then transferred to the transmission processing unit 210 by the data reading unit 500. The area in which the packet that has become unnecessary after the transfer is stored is used to store the received packet again. Therefore, at the end of the packet transfer, the data reading means 500 notifies the data writing means 300 of the release of the area. To do.

Details of the data writing means 300 and the data reading means 500 will be described below.

First, details of the data writing means 300 will be described with reference to FIG. The data writing means 300 is
A counter 310 that counts the packet length, a unit length storage unit 330 that stores two different unit lengths, and a counter 310.
A selection circuit A341 that selects one of the two unit lengths based on the value of, a data write address generation unit 380, and a control circuit 390 that controls them.

The network interface 220 controls the start of packet reception by the control circuit 3 prior to receiving the packet.
Notify 90. The control circuit 390 resets the counter 310 and starts counting the packet length. When a packet is sent from the network interface 220, the data write address generation unit 380 outputs the address for storing the packet to the data storage means 700, and the packet is allocated to the area as shown in FIG. The first 1 word of is opened and stored. The opened word is used as a data length storage area 410.

The address output from the data write address generator 380 is always the write area end address data 37.
0 is compared by the comparison circuit 385, and the data storage area 7
It is monitored by the control circuit 390 so as not to destroy other data in 00. If the unused area becomes insufficient during the storage of the packet, the packet is discarded. Regarding the discarding of a packet, the unused area length may be calculated in advance, and reception of the packet may be permitted only when it is larger than the maximum length of the packet.

When the reception of one packet ends, the network interface 220 notifies the control circuit 390 of the end of packet reception. The selection circuit A341 selects the unit length of the unit length storage means 330 based on the value of the counter 310 at that time. The selected unit length becomes the length of the area allocated for storing the packet. Whether the length of the area occupied by the packet is the unit length A810 or the unit length B820 is recorded in the data length storage area 410. In the data length storage area 410, the value of either the unit length A recording code 561 indicating that the area occupied by the packet is the unit length A 810 or the unit length B recording code 562 indicating the unit length B 820 is stored. Will be recorded. Unit length recording code A
561 and unit length B recording code B562 are registered in the data length recording means 320 in advance, and the counter 31
An appropriate recording code is selected based on the value of 0 and recorded in the data length storage area 410.

After the storage of one packet is completed and the unit length A recording code 561 or the unit length B recording code 562 is recorded in the data length storage area 410, the unit length selected by the selecting circuit A 341 is written by the adding circuit 351. An area having an appropriate unit length is added to the packet by adding it to the start address 360.

To release the allocated area, the control circuit 390, which receives the area release notification signal 510 from the data reading means 500, gives an instruction to the selection circuit B 342 so that the selected unit length is the write area end address 37.
It is performed by adding to 0.

Next, details of the data reading means will be described with reference to FIG. The data reading means 500 starts transfer by the transfer start signal 120 of the processor 110. First, the value of the data length storage area 410 is the value of the comparison circuit 55.
0, and it is discriminated whether it is the unit length A recording code 561 or the unit length B recording code 562. The control circuit 545 controls the transfer based on the result. After the transfer,
Unit length A81 at the data read area start address 535
0 or unit length B820 is added.

At the end of the transfer of one packet, the data reading means 500 informs the data writing means 300 by means of the area release notification signal 510 which of the unit length A810 and the unit length B820 is to be released.

Next, the storage area management in this embodiment will be described by showing a concrete example. It is assumed that the packet handled by the inter-network connecting device of this embodiment has a maximum size of 1500 bytes and a minimum size of 48 bytes. If the packet length distribution is 25% for packets of 64 bytes or less, 65% for packets of 1500 bytes, and 10% for packets of other lengths, the unit length A810 is 64 bytes, and the unit length B82 is
When 0 is set to 1500 bytes, the waste of memory is suppressed to about 10% of all packets.

On the other hand, in the method of allocating a fixed length area having a short fixed length, for example, 64 bytes as much as necessary, the waste of the storage area is reduced, but calculation of the size of the area to be allocated to the packet and A logic circuit is needed for the calculation of the pointer update. Further, in the 64-byte unit allocation, since 1 to 24 areas are allocated to one packet, a lot of resources for recording the area length are required. In this embodiment, for example, the unit length A recording code 561 is set to 0. By assigning the unit length B recording code 562 to 1, recording can be performed with 1 bit, and the resource for recording the area size can be reduced.

As described above, in the storage area management using the present invention, by allocating the storage area in which the distribution of the data length is reflected, it is possible to manage the area with little waste by a simple process.

Next, another embodiment of the present invention is shown in FIG. In this embodiment, a storage area management processor 630 is prepared in the data buffer 600, and the storage area is managed by software. The data length recording means is realized as a program, and the unit length is stored as a constant on the program or as data on the program memory 640.
It can be changed from the outside. Data storage means 6
The method of allocating the area in 05 is the same as that of the embodiment of FIG.

When data is externally input to the data buffer 600, the write DMA controller 610
Starts counting the data length with the counter 611. The storage area management processor 630 compares the counter value 611 with a plurality of different unit lengths described in the software to select an appropriate unit length, and stores the unit length recording code in the data length storage area of the data storage means 605. Record 615. At the same time, the selected unit length is added to the write area start address 614 managed by software, and it is written D
Notify the address generation circuit 612 of the MA controller 610. Data input next from the outside is stored from this address.

When the transfer start signal 623 is sent to the data buffer device 600, the storage area management processor 630 checks the unit length recording code 615 of the data length storage area, calculates the data length to be transferred, and reads it out. The address generation circuit 621 of 620 is notified of the transfer length 622. When the read DMA controller 620 finishes the transfer of the designated transfer length, it notifies the storage area management processor 630 of the transfer end by the transfer end notification signal 621. The storage area management processor 630 updates the write area end address managed by software.

In the embodiment of FIG. 6, the function realized by hardware in the embodiment of FIG. 1 is realized by software, and the hardware part can be simplified and the unit length can be changed from the outside. There is.

Although the present invention has been described with reference to the embodiments, the data buffer device of the present invention can be applied not only to the communication device but also to a wide range.

[0028]

As described above, according to the present invention, storage area management with little waste of storage area can be realized without complicated processing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a data buffer according to the present invention.

FIG. 2 is a block diagram showing a communication device using the embodiment of FIG.

FIG. 3 is a detailed block diagram of a data writing unit of the embodiment of FIG.

FIG. 4 is an explanatory diagram of packet storage in the embodiment of FIG.

5 is a detailed block diagram of a data reading means of the embodiment of FIG.

FIG. 6 is a block diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 Reference numeral 100 ... Reception processing unit, 200 ... Network connection device, 300 ... Data writing means, 320 ... Data length recording means, 330, 520 ... Unit length storage means, 410, 721, 722, 723 ... Data length storage area, 500 ... Data reading means, 561 ... Unit length A recording code, 562 ... Unit length B recording code, 605, 700 ... Data storage means, 719 ... Data storage area, 810 ... Unit length A, 820 ... Unit length B.

Claims (7)

[Claims] 1. A data storage means for storing a plurality of data, a unit length storage means for storing a plurality of different unit lengths, and a unit length corresponding to each of the plurality of data stored in the data storage means. Data length storage means for storing,
Data length recording means for recording the unit length corresponding to each data in the data length storage means is provided, and the length of the area to be allocated to each data among the plurality of unit lengths stored in the unit length storage means. A storage area management system characterized in that the data length recording means records the unit length in the data length storage means, the unit length being equal to the shortest unit length among the unit lengths having a value equal to or larger than the data length. 2. A data buffer using the storage area management system according to claim 1. 3. The data buffer according to claim 2, wherein the data length storage means is realized as an area in the data storage means. 4. A storage area management system according to claim 1, wherein a plurality of unit lengths stored in said unit length storage means can be changed from the outside. 5. The storage area management method according to claim 1, wherein a data length having a large probability is set as a unit length in a probability distribution of the length of data to be stored. 6. A communication device, wherein the data buffer according to claim 2 or 3 is used as a packet buffer. 7. A storage area management system according to claim 1, wherein the maximum length of data stored in said data storage means is set as one of unit lengths.