JP2943710B2 - Buffer busy control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buffer control system, and more particularly to a method for controlling a reception data buffer suitable for use in an information processing apparatus such as a computer. The control method to be performed.

[0002]

2. Description of the Related Art This type of conventional method of busy control of a reception data buffer is performed by comparing a predetermined value set first with a remaining capacity of the buffer. For example, JP
Japanese Patent Publication No. 233745 proposes a method of providing a transmission buffer number register in which a predetermined number of buffers is set, comparing this value with the number of empty buffers, and outputting a transmission suspension request. FIG. 4 shows the configuration of the buffer device proposed in the above publication.

In FIG. 4, reference numeral 110 denotes a management unit, which is provided in the transmission data processing unit 107 and manages a transmission once stop request / release. Reference numeral 105 denotes a transmission buffer number register, in which a predetermined buffer number B is initialized. Reference numeral 104 denotes an empty buffer number register, in which the current empty buffer number N is set. The management unit 110 compares the number N of empty buffers with the predetermined number B of buffers initially set in the number-of-transmission-buffers register, and outputs a transmission suspension request 121a to the CPU 101 if N ≦ B.

When the number N of free buffers recovers to N> B, the transmission suspension request is released.

[0005]

However, when the above-described conventional buffer device is applied to variable-length data transfer, there is a problem that the buffer utilization rate is deteriorated. The reason is as follows.

That is, in the conventional buffer device, a fixed value is used as the predetermined buffer amount even for variable-length data transfer. Then, the maximum value of the amount of data that may be transferred from the transmission source is set to the fixed value so that the buffer does not overflow. Therefore, when transferring variable-length data,
Even if the next data to be actually transferred can be stored in the reception buffer, control is performed so that the next transfer is not executed until the remaining amount of the reception buffer reaches the predetermined buffer amount.

With such a control method, in the prior art, when transferring variable-length data, the use efficiency of the receiving buffer and the utilization rate of the data transfer path are reduced.

Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a busy control method for improving the use efficiency of a data reception buffer.

[0009]

To achieve the above object, according to an aspect of the present invention, in the control of data transfer between devices, feed
In this transfer data to the receiving apparatus from the signal-side device is notified to the receiving side device present and the transfer amount of the next transfer to continue (referred to as "next transfer amount") is set, the receiving
In the receiving device, the next transfer amount and the free space of the reception buffer
And making a busy determination of the reception buffer to increase the use efficiency of the reception buffer.

According to the present invention, in a buffer control method of a data receiving apparatus including a receiving buffer for storing received data, the data receiving apparatus is configured to transfer data from a data transmitting apparatus.
The next transfer data transfer amount ("Next transfer
If that Okuryou ") is set, a holding means for holding the next transfer amount, the remaining capacity of the reception buffer, only when it becomes below said next transfer amount, to the data transmitting apparatus It is characterized in that a reception buffer busy signal is transmitted and control is performed so as to wait for data transmission.

In the present invention, when the next transfer amount information cannot be obtained from the data transmitting device, a predetermined value is set as the next transfer amount in the data receiving device. And

Further, in the present invention, the data transferred from the data transmitting apparatus is a variable length data, and the current transfer amount and the next transfer amount information are transmitted together with the current transmission data. When the next transfer data does not exist, the identification code is stored as the next transfer amount information in a predetermined manner.

The outline of the present invention will be described below. According to the present invention, when a data transfer to be requested next already exists in the transmission module at the time of data transfer, the transfer amount is set to a predetermined data position to determine the presence of the next transfer and the transfer thereof. The function of indicating the quantity to the receiving module is provided. At the same time, the receiving module is provided with a data length holding buffer (26 in FIG. 1) for holding the next transfer amount sent from the transmitting module and comparing it with the remaining capacity of the received data buffer.

[0014]

When the transmitting module holds data to be continuously transferred, the receiving module sequentially stores the notified next transfer amount in the data length holding buffer and the value stored in the data length holding buffer. The busy control is performed in comparison with the remaining capacity of the receiving buffer, so when the sending module holds a large amount of transfer data, even if the data transfer amount of the sending module is variable length, the buffer space for the next transfer amount is available. If the capacity is secured, the busy can be released immediately.

[0015]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention. Referring to FIG. 1, an embodiment of the present invention comprises:
The transmission module 1 and the reception module 2 are connected by a data transfer path 3. The transmission module 1 includes a transmission data buffer 11 and a transmission control device 12.

The receiving module 2 includes a receiving data buffer 21 for storing the transferred data,
The circuit includes a data buffer free space calculation circuit 24, a specified value register 25, a data length holding buffer 26, and a busy control circuit 27.

The busy control circuit 27 of the receiving module 2 is connected to the transmission control device 12 of the transmitting module 1.

Next, the operation of the embodiment of the present invention will be described.

Referring to FIG. 1, transmission data 100 stored in transmission data buffer 11 of transmission module 1 is transmitted.
To 103 are sequentially transferred to the reception module 2 and stored in the reception data buffer 21. Receive data buffer 2
1 includes an in-use area 22 and an unused area 22, and a free space (capacity of an unused area) in the reception data buffer 21 is calculated by a data buffer free space calculation circuit 2.
4 and is reported to the busy control circuit 27.

The busy control circuit 27 compares the data buffer free capacity supplied from the data buffer free capacity calculation circuit 24 with the value of the data length holding buffer 26,
When the free space of the data buffer is smaller, the transmission controller 12 of the transmission module 1 is notified by a reception data buffer busy signal 28.

The value of the data length holding buffer 26 is updated to the next transfer amount sent from the transmission module 1 for each data transfer, and is set in the specified value register 25 if the next transfer amount is not sent. Is updated to the value that has been set.

In the specified value register 25, a value unique to the transmission module 1 is set in the initial setting.

Next, the operation of the receiving module 2 will be described below with reference to the flowcharts shown in FIGS.

After the processing is started, first, an initial set value is set in the specified value register 25 (step 301).

Next, the value of the specified value register 25 is set in the data length holding buffer 26 as the next transfer amount (step 302).

Next, the busy control circuit 27 compares the free space of the reception data buffer 21 with the value of the data length holding buffer 26. If the value of the data length holding buffer 26 is larger, the busy control circuit 27 A busy signal is sent to the transmission control circuit 12 of the above, and a wait state is set until a free space equal to or larger than the value of the data length holding buffer 26 is secured in the reception data buffer 21 (steps 303 to 305).

On the other hand, in the determination of step 303, the free space of the reception data buffer 21 is
If it is larger than the value of 6, it is further checked whether or not a busy signal is being transmitted (step 307). If the busy signal is being transmitted, the busy signal is released (step 310) and the next data Make the transfer executable. Then, the transmission module 1 includes the transmission data buffer 11
Is transferred to the receiving module 2 (step 311).

The receiving module 2 checks whether or not the next transfer length is set in the transfer data (step 312). If the next transfer length is not set (no in step 312), the data length is determined. The value of the holding buffer is updated to the value of the specified value register (step 302).

On the other hand, if the next transfer length is set (Yes in step 312), the value of the data length holding buffer is updated to the next transfer length (step 315).

The above embodiment of the present invention will be described in detail with reference to examples.

FIG. 2 is a diagram for explaining an embodiment of the present invention, and shows an example of a format of data transferred from the transmission module 1 to the reception module 2.

Referring to FIG. 2, when data is transferred, transmission module 1 places the current transfer amount 20 in a predetermined position.
The transmission data 202 is transmitted by setting 0 and the next transfer amount 201.

The value of the next transfer amount 201 is set when the next data transfer data already exists in the transmission data buffer 11 of the transmission module 1. on the other hand,
If the data to be transferred this time is the last data transfer in the transmission data buffer 11, that is, if there is no next transfer data in the transmission data buffer 11, a predetermined value, for example, “ By setting “0” or the like, it indicates that there is no data waiting to be transmitted in the transmission module 1 in the transmission data buffer 11.

When the transmitting module 1 indicates that the next transfer data does not exist, the data amount of the next data transfer to be executed is unknown, so the receiving module 2
Updates the value of the data length holding buffer 26 to the value of the specified value register 25 in preparation for a new next transfer.

[0036]

As described above, according to the present invention,
When the transmission module holds a plurality of transfer data, the notified next transfer amount is sequentially compared with the remaining capacity of the reception buffer to perform busy control, and even when the data transfer amount of the transmission module is a variable length, The busy can be released immediately after the buffer space for the next transfer amount is secured, so when the transmission module holds a large amount of transfer data such as a transmission wait state, it is necessary to efficiently use the reception buffer. The effect is that it can be done.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram for explaining one embodiment of the present invention;
FIG. 3 is a diagram illustrating an example of a configuration of a transfer data format.

FIG. 3 is a flowchart for explaining the operation of the exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional buffer device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transmission module 2 reception module 12 transmission control device 21 reception data buffer 22 area in use 23 unused area 24 data buffer free space calculation circuit 25 prescribed value register 26 data length holding buffer 27 busy control circuit 100 to 103 transmission data 200 Current transmission data length 201 Secondary data transfer amount 202 Transmission data

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁶ identification code FI G06F 13/38 310 G06F 13/38 310B (58) Field surveyed (Int.Cl. ⁶ , DB name) G06F 5/06 313 B41J 5/30 B41J 21/00 G06F 3/12 G06F 13/00 353 G06F 13/38 310

Claims (4)

(57) [Claims] In the control of data transfer between devices, the present transfer data from a transmitting device to a receiving device includes:
Presence and amount of transfer following the transfer to continue (referred to as "next transfer amount") is notified to the receiving side apparatus is set, the the receiving side apparatus compares the free space of the receiving buffer and the next transfer amount A buffer control device for determining the busy state of the reception buffer to increase the use efficiency of the reception buffer. 2. A buffer control method for a data receiving apparatus including a receiving buffer for storing received data, wherein the data receiving apparatus is configured to transfer data from a data transmitting apparatus.
The transfer amount of the next transfer data (“Next transfer
If that amount ") is set, a holding means for holding the next transfer amount, the remaining capacity of the reception buffer, only when it becomes below said next transfer amount, received by the data transmitting apparatus A buffer control method for transmitting a buffer busy signal and controlling to wait for data transmission. Wherein when said data transmission next transfer amount information from the device side is not obtained, the data receiving apparatus, preset predetermined value set <br/> constant in the holding means as the next transfer amount 3. The buffer control method according to claim 2, wherein the control is performed. 4. The data transferred from the data transmitting device is a variable length data and data, and the current transfer amount and the next transfer amount information are transferred to the data receiving device together with the current transmission data. 3. The buffer control method according to claim 2, wherein when there is no next transfer data, a predetermined identification code is stored as next transfer amount information.