JP5644531B2 - Data transfer apparatus and data transfer method - Google Patents

Description

  The present invention relates to a data transfer apparatus and a data transfer method.

  Conventionally, a data transfer device transfers data stored in each of a plurality of buffers to, for example, one transfer destination device (see, for example, Patent Document 1). The plurality of buffers are connected to one data bus. Each buffer stores data transmitted from a device connected thereto. When data transfer is performed, the data transfer device transmits a request signal to the arbitration unit in order to obtain a transmission permission (occupation right) for transmitting data to the data bus. The data transfer apparatus that has obtained the transmission permission transmits the data stored in the buffer corresponding to the transmission permission to the transfer destination via the data bus.

JP-A-4-37941

  However, in the data transfer method as described above, after all the data in the buffer that has obtained the transmission permission is transferred, the transmission permission is given to another buffer (another device). Since a buffer with a large data size occupies the data bus for a long time, the data transfer of other buffers is waited for a long time.

  An object of this data transfer apparatus is to reduce the waiting time during data transfer of each buffer connected to a shared data bus.

According to an aspect of the present invention, a division size calculation unit that calculates a division size based on data accumulation amounts of a plurality of buffers, and a plurality of buffers corresponding to the plurality of buffers, according to the division size and the data accumulation amount. a plurality of divided transfer control section for outputting a transfer instruction of the corresponding buffer Te, the transfer instruction seen including and a transfer control unit that transfers the data to the transfer destination from the buffer in response to the division size calculation unit A plurality of time prediction units for calculating respective predicted times until the next transfer request is issued based on the data accumulation amounts of the plurality of buffers, and a plurality of the predicted times based on the transfer rate of the bus. A plurality of size conversion units that respectively convert the plurality of division sizes .

  According to one aspect of the present invention, the waiting time during data transfer can be reduced.

1 is a schematic block diagram of a data transfer system. It is a schematic block diagram of a division size calculation unit. It is a process flowchart of a division transfer control part. It is explanatory drawing which shows the data accumulation amount and transfer timing of each buffer. It is explanatory drawing which shows the data accumulation amount and transfer timing of each buffer. It is explanatory drawing which shows the data accumulation amount and transfer timing of each buffer. It is a schematic block diagram of the data transfer system in another example. It is a schematic block diagram of the division size calculation part in another example.

Hereinafter, an embodiment will be described with reference to FIGS.
As shown in FIG. 1, a plurality (two in FIG. 1) of communication devices 11 a and 11 b are connected to a data bus 13 via buffers 12 a and 12 b, respectively, and the data bus 13 is connected via a data transfer device 20. It is connected to a target device 14 that is a transfer destination.

  Data from each of the communication devices 11a and 11b is transferred to the buffers 12a and 12b, respectively, and the data transfer device 20 that controls the transfer of the data in the buffers 12a and 12b is permitted to communicate with the target device 14. Data transfer via the data bus 13 is enabled. Each of the buffers 12a and 12b is, for example, a FIFO (First In First Out) memory in which data writing and data reading are controlled by a write pointer and a read pointer. Each of the buffers 12a and 12b outputs data accumulation amounts Dsa and Dsb calculated based on, for example, a write pointer and a read pointer.

  The division size calculation unit 21 is supplied with data accumulation amounts Dsa and Dsb from the buffers 12a and 12b. Various information is supplied from the control unit 22 to the division size calculation unit 21.

  The control unit 22 stores a transfer rate Rta corresponding to the buffer 12a, a transfer rate Rtb corresponding to the buffer 12b, and a transfer rate Rt0 corresponding to the data bus 13. Each transfer rate Rta, Rtb, Rt0 is set according to the frequency of a clock signal used for data transfer, for example. Further, the control unit 22 stores a threshold value Bia corresponding to the buffer 12a and a threshold value Bib corresponding to the buffer 12b. The control unit 22 outputs each transfer rate Rta, Rtb, Rt0 and each threshold value Bia, Bib.

  The division size calculation unit 21 divides the division sizes Bsa and Bsb corresponding to the buffers 12a and 12b based on the transfer rates Rta, Rtb, and Rt0, the data storage amounts Dsa and Dsb, and the threshold values Bia and Bib. Is calculated. Specifically, the division size calculation unit 21 performs division corresponding to the buffer 12a based on the transfer rate Rtb, the data accumulation amount Dsb, the threshold value Bib corresponding to the buffer 12b, and the transfer rate Rt0 corresponding to the data bus 13. The size Bsa is calculated. Further, the division size calculation unit 21 determines the division size corresponding to the buffer 12b based on the transfer rate Rta, the data accumulation amount Dsa, the threshold Bia corresponding to the buffer 12a, and the transfer rate Rt0 corresponding to the data bus 13. Bsb is calculated.

  The division size Bsa corresponding to the buffer 12a is supplied to the division transfer control unit 23a. The division size Bsb corresponding to the buffer 12b is supplied to the division transfer control unit 23b. The control unit 22 outputs transfer instructions Tsa and Tsb to the divided transfer control units 23a and 23b at an arbitrary timing.

  The division transfer control unit 23a performs arbitration at a timing based on the transfer instruction Tsa output from the control unit 22, the data accumulation amount Dsa output from the buffer 12a, and the division size Bsa output from the division size calculation unit 21. The transfer instruction Tba based on the division size is output to the unit 24. The transfer instruction Tba includes the amount of data transferred from the corresponding buffer 12a to the transfer destination device 14.

  Similarly, the division transfer control unit 23b performs timing based on the transfer instruction Tsb output from the control unit 22, the data accumulation amount Dsb output from the buffer 12b, and the division size Bsb output from the division size calculation unit 21. Then, the transfer instruction Tbb based on the division size is output to the arbitration unit 24. The transfer instruction Tbb includes the amount of data transferred from the corresponding buffer 12b to the transfer destination device 14.

  The arbitration unit 24 arbitrates transfer instructions Tba and Tbb output from the divided transfer control units 23 a and 23 b and outputs a transfer instruction Tbs according to the arbitration result to the transfer control unit 25. The transfer instruction Tbs includes selection information for selecting a buffer to be transferred, and transfer size information indicating the amount of data transferred from the selected buffer.

  The transfer control unit 25 transfers data of a specified size from the transfer source buffer to the transfer destination device 14 in accordance with the transfer instruction Tbs from the arbitration unit 24. That is, the transfer control unit 25 selects one of the buffers 12a and 12b as a transfer source according to the selection information included in the transfer instruction Tbs. Then, the transfer control unit 25 transfers data of the transfer size included in the transfer instruction Tbs from the selected buffer to the transfer destination device 14.

Next, the division size calculation unit 21 will be described in detail.
As illustrated in FIG. 2, the division size calculation unit 21 includes a time prediction unit 31a corresponding to the buffer 12a and a time prediction unit 31b corresponding to the buffer 12b.

The time prediction unit 31a and the time prediction unit 31b correspond to the data storage status of the buffers other than the buffers corresponding to each other. The corresponding buffer time prediction unit 31a and the time prediction unit 31b store the data in the buffers other than the corresponding buffers. Calculate time. That is, the time predicting unit 31a calculates the time (data storage time) Tpb required to store a predetermined amount (threshold value Bib) of data in the buffer 12b. The time prediction unit 31b calculates a time (data storage time) Tpb required to store a predetermined amount (threshold value Bia) of data in the buffer 12a.

More specifically, information corresponding to the buffer 12b shown in FIG. 1 is input to the time prediction unit 31a. Information corresponding to the buffer 12b includes a data accumulation amount Dsb, a transfer rate Rtb, and a threshold value Bib. When the data accumulation amount Dsb of the buffer 12b is equal to or less than the threshold value Bib, the time prediction unit 31a calculates the data accumulation time Tpb until the next transfer request is issued by the following equation:
Tpb = Rtb / (Bib−Dsb)
Calculated by When the data accumulation amount Dsb of the buffer 12b is equal to or greater than the division size threshold value Bib, the time prediction unit 31a calculates the time until the next transfer request is issued as “0 (zero)”, that is, The transfer is enabled.

  The buffer 12b can transfer data when it accumulates a predetermined amount or more of data. That is, it becomes possible to issue a transfer request to the buffer 12b. That is, the time prediction unit 31a calculates a predicted time until the next transfer request can be issued to the buffer 12b based on various pieces of input information.

Similarly, the time prediction unit 31b calculates a predicted time until the next transfer request can be issued to the buffer 12a based on various pieces of input information. That is, information corresponding to the buffer 12a shown in FIG. 1, that is, the data accumulation amount Dsa, the transfer rate Rta, and the threshold value Bia are input to the time prediction unit 31b. Based on the information (Dsa, Bia, Rta) corresponding to the buffer 12a, the time prediction unit 31b calculates the data accumulation time Tpa until the next transfer request is issued by the following equation:
Tpa = Rta / (Bia-Dsa)
Calculated by Then, when the data accumulation amount Dsa of the buffer 12a is equal to or greater than the threshold value Bia, the time predicting unit 31b calculates the time until the next transfer request is issued as “0 (zero)”, that is, the transfer enabled state. And

  The size conversion units 32a and 32b convert the data storage times Tpa and Tpb calculated by the time prediction units 31a and 31b into the predicted sizes Psa and Psb of the data transferred from the corresponding buffers 12a and 12b. The size conversion unit 32a converts the data accumulation time Tpb corresponding to the buffer 12b into the predicted size Psa corresponding to the buffer 12a. The size conversion unit 32b converts the data storage time Tpa corresponding to the buffer 12a to the predicted size Psb corresponding to the buffer 12b.

  The buffer 12a can occupy the data bus 13 while the data is stored in the buffer 12b. The amount of data that can be transferred during the occupation period is determined by the product of the period for transferring data and the speed for transferring data from the buffer 12a. The speed at which data is transferred from the buffer 12a corresponds to the transfer rate between the buffer 12a and the transfer destination device 14, that is, the transfer rate Rt0 of the data bus 13. Therefore, the size converter 32a multiplies the data accumulation time Tpb corresponding to the buffer 12b calculated by the time predictor 31a by the transfer rate Rt0 of the data bus 13 to calculate the predicted size Psa corresponding to the buffer 12a.

  Similarly, during the period in which data is stored in the buffer 12a, the buffer 12b can occupy the data bus 13, and the amount of data that can be transferred during the occupancy period is determined by the product of the occupation period and the transfer rate Rt0 of the data bus 13. It is done. Therefore, the size converter 32b multiplies the data accumulation time Tpa corresponding to the buffer 12a calculated by the time predictor 31b by the transfer rate Rt0 of the data bus 13 to calculate the predicted size Psb corresponding to the buffer 12b.

  The predicted size Psa corresponding to the buffer 12a calculated by the size converting unit 32a is supplied to the clip processing unit 33a. In addition, the upper limit value Bamx and the lower limit value Bamn of the division size are supplied from the register 34 to the clip processing unit 33a. The upper limit value Bamx and the lower limit value Bamn of the division size are set according to, for example, the number of buffers, overhead related to transfer, and the like, and are stored in the register 34.

  When one buffer occupies the data bus, the other buffers cannot perform the transfer. If the transfer amounts in all the buffers are the same value, the number of times transfer is permitted for each buffer per unit time is inversely proportional to the number of buffers. Therefore, as the number of buffers increases, the waiting time until each buffer can be transferred corresponds to the result of multiplying the number of buffers by the amount of data to be transferred. For this reason, setting the upper limit of the amount of data to be transferred suppresses an increase in waiting time.

  Further, in one data transfer, it is necessary to transmit the transfer source information and header information including the amount of data to be transferred to the transfer destination device 14. Regardless of the amount of data transferred by one data transfer, header information of a certain size is required. For this reason, if the division size is reduced and the number of transfers increases, the number of times header information is transmitted increases, and the effective data transfer amount, that is, the transfer period (the period in which header information and data are transferred) is increased. The ratio of the data transfer period is reduced. For this reason, setting a lower limit value of the amount of data to be transferred suppresses a decrease in transfer efficiency.

  The clip processing unit 33a outputs a divided size Bsa that is equal to the predicted size Psa when the predicted size Psa is equal to or less than the upper limit value Bamx of the split size and equal to or higher than the lower limit value Bamn. On the other hand, when the predicted size Psa is less than the lower limit value Bamn, the clip processing unit 33a outputs a division size Bsa that is equal to the lower limit value Bamn. In addition, when the predicted size Psa is larger than the upper limit value Bamx, the clip processing unit 33a outputs a division size Bsa that is equal to the upper limit value Bamx.

  Similarly, the clip processing unit 33b outputs a divided size Bsb equal to the predicted size Psb when the predicted size Psb is equal to or smaller than the upper limit value Bbmx and lower limit value Bbmn of the divided size. On the other hand, when the predicted size Psb is less than the lower limit value Bbmn, the clip processing unit 33b outputs a division size Bsb equal to the lower limit value Bbmn. Further, when the predicted size Psb is larger than the upper limit value Bbmx, the clip processing unit 33b outputs a division size Bsb equal to the upper limit value Bbmx.

Next, an example of processing (divided transfer control) executed by the divided transfer control units 23a and 23b will be described with reference to FIG. Refer to FIGS. 1 and 2 for members described below.
The division transfer control unit 23a performs transfer control on the buffer 12a, and the division transfer control unit 23b performs transfer control on the buffer 12b. The divided transfer control units 23a and 23b have different target buffers, and the processes to be executed are the same. Therefore, in the description of the flowchart shown in FIG. 3, the division transfer control unit 23a will be described, and the description of the division transfer control unit 23b will be omitted.

The division transfer control unit 23 a receives the information on the division size Bsa from the division size calculation unit 21 together with the transfer instruction Tsa from the control unit 22 and starts the operation.
First, the divided transfer control unit 23a clears (= 0) the number of transferred data Tzs in consideration of the previous transfer (step S10).

  Next, the division transfer control unit 23a determines the size relationship between the difference between the transfer data number Tds and the transferred data number Tzs and the division size Bsa (step S11: YES). When the difference between the transfer data number Tds and the transferred data number Tzs is larger than the division size Bsa (step S11: YES), the division transfer control unit 23a sets the division size Bsa to the transfer size JTs (step S12). On the other hand, when the difference between the transfer data number Tds and the transferred data number Tzs is equal to or smaller than the split size Bsa (step S11: NO), the divided transfer control unit 23a determines the difference between the transfer data number Tds and the transferred data number Tzs. The value is set to the transfer size JTs (step S13).

  Next, the division transfer control unit 23a monitors the data accumulation amount Dsa of the buffer 12a, and determines whether or not there is data for the division size Bsa in the buffer 12a (step S14). If the division transfer control unit 23a determines that data for the division size Bsa is not accumulated in the buffer 12a (step S14: NO), the division transfer control unit 23a does not proceed to the next step. If the division transfer control unit 23a determines that data of the division size Bsa is stored in the buffer 12a (step S14: YES), the division transfer control unit 23a outputs a transfer start request Req to the arbitration unit 24 (step S15).

  The division transfer control unit 23a determines whether or not the transfer start request Req has been received by the arbitration unit 24 (step S16). Upon receiving the transfer start request Req, the arbitrating unit 24 transmits, for example, a transfer permission signal to the transmission start request Req transmission source.

  When the division transfer control unit 23a does not receive the transfer permission signal (step S16: NO), the division transfer control unit 23a does not proceed to the next step. On the other hand, when receiving the transfer permission signal, the division transfer control unit 23a determines that the transfer start request Req has been received (step S16: YES), and issues a transfer instruction Tba to the transfer control unit 25. That is, the division transfer control unit 23a issues transfer settings to the transfer control unit 25 (step S17). The transfer setting includes information for specifying a transfer source and a transfer destination for transferring data, and an amount of data to be transferred. The division transfer control unit 23 a transmits information indicating the buffer 12 a as a transfer source, information indicating the device 14 as a transfer destination, and a transfer size JTs to the transfer control unit 25.

Next, the divided transfer control unit 23a issues a transfer start instruction to the transfer control unit 25 (step S18).
When receiving the transfer start instruction, the transfer control unit 25 transfers data according to the transfer setting. In this case, the transfer control unit 25 outputs the data output from the buffer 12a to the device 14. Then, when the transfer control unit 25 completes the transfer of the transfer size JTs, it issues a transfer completion notification.

  Next, the division transfer control unit 23a determines whether or not there is a transfer completion notification (step S19). The division transfer control unit 23a does not proceed to the next step when there is no transfer completion notification (step S19: No). On the other hand, when receiving the transfer completion notification (step S19: YES), the divided transfer control unit 23a adds the current transfer size JTs (divided size Bsa) to the number of transferred data Tzs (step S20).

  Next, the divided transfer control unit 23a determines whether or not the transfer for the transfer data number Tds is completed (step S21). When the transferred data number Tzs is smaller than the transfer data number Tds, the divided transfer control unit 23a determines that the transfer for the transfer data number Tds has not been completed (step S21: NO), and proceeds to step S11. That is, each process from step S11 to step S20 is repeatedly executed until the data transfer for the transfer data number Tds is completed. Then, when the transferred data number Tzs becomes equal to the transfer data number Tds, the divided transfer control unit 23a determines that the transfer for the transfer data number Tds is completed (step S21: NO), and ends the split transfer control process. .

Next, an operation example of the data transfer apparatus 20 will be described.
(First operation example)
As shown in FIG. 4, at time t0, all data to be transferred is accumulated in the buffer 12a, and this data accumulation amount is larger than the threshold value Bia. On the other hand, less data than the threshold value Bib is stored in the buffer 12b.

  The division size calculation unit 21 calculates the division sizes Bsa and Bsb based on the data accumulation amounts Dsa and Dsb of both the buffers 12a and 12b, respectively. The divided transfer control unit 23a outputs the transfer instruction Tba because the data accumulation amount Dsa is larger than the threshold value Bia. On the other hand, the divided transfer control unit 23b does not output the transfer instruction Tbb because the data accumulation amount Dsb is smaller than the threshold value Bib. As a result, the arbitrating unit 24 outputs a transfer instruction Tbs including the division size Bsa to the transfer control unit 25.

  The transfer control unit 25 starts transfer with the transfer size JTs to the buffer 12a in accordance with the transfer instruction Tbs. The transfer control unit 25 first transmits a header corresponding to the buffer 12 a and transfers the data read from the buffer 12 a to the device 14. As data is transferred from the buffer 12a, the data storage amount Dsa of the buffer 12a decreases.

The data transfer to the buffer 12a (denoted as “A1” in the figure) is completed at time t1 when the data accumulation amount Dsb of the buffer 12b is near the threshold value Bib.
Next, at time t1, the division size calculation unit 21 calculates the division sizes Bsa and Bsb based on the data accumulation amounts Dsa and Dsb of both buffers 12a and 12b, respectively. The division transfer control units 23a and 23b output transfer instructions Tba and Tbb. The arbitration unit 24 outputs a transfer instruction Tbs with the division size Bsb as the transfer size JTs to the transfer control unit 25 based on the arbitration result. The transfer control unit 25 starts data transfer to the buffer 12b in accordance with the transfer instruction Tbs. That is, the transfer control unit 25 transmits a header corresponding to the buffer 12 b and transfers the data read from the buffer 12 b to the device 14. The data transfer to the buffer 12b (denoted as “B1” in the drawing) is completed after transferring the transfer size JTs, that is, the data of the calculated division size Bsb.

  Next, at time t2, the division size calculation unit 21 calculates the division sizes Bsa and Bsb based on the data storage amounts Dsa and Dsb of both the buffers 12a and 12b, respectively. At this time, since the data accumulation amount Dsb in the buffer 12b is smaller than the data accumulation amount Dsb at time t0, the division size calculation unit 21 calculates a division size Bsa having a larger value than the division size Bsa at the same time t0. Then, transfer of the transfer size JTs (divided size Bsa) is started to the buffer 12a. The data transfer to the buffer 12a (denoted as “A2” in the figure) is completed at time t3 when the data accumulation amount Dsb of the buffer 12b is near the threshold value Bib.

  Next, at time t3, similarly to time t1, the arbitrating unit 24 outputs a transfer instruction Tbs according to the transfer instruction Tbb including the division size Bsb, and the transfer control unit 25 performs data transfer to the buffer 12b according to the transfer instruction Tbs. Transfer (denoted as “B2” in the figure) is started.

  Thus, based on the data storage amount Dsb of the buffer 12b, the data storage time Tpb until data of the threshold value Bib or more is stored in the buffer 12b is predicted, and from the buffer 12a according to the data storage time Tpb. The division size Bsa of the data to be transferred is calculated. Therefore, when the data transfer to the buffer 12a is completed, the data transfer to the buffer 12b is possible, so that the data transfer to the buffer 12b can be started. For this reason, the waiting time for data transfer in the buffer 12b can be shortened.

  Further, based on the data accumulation amount Dsb of the buffer 12b, a data accumulation time Tpb until data of the threshold value Bib or more is accumulated in the buffer 12b is predicted and transferred from the buffer 12a according to the data accumulation time Tpb. The data division size Bsa is calculated. The smaller the data accumulation amount Dsb in the buffer 12b, the larger the division size Bsa. Therefore, the data in the buffer 12a can be transferred together by one header, and the overhead in data transfer can be reduced compared to the case where the data is divided into a predetermined size and transferred in multiple times.

(Second operation example)
In this operation example, the transfer rate (transfer rate) for transferring data from the device 11b to the buffer 12b is lower than the set transfer rate Rtb. In FIG. 5, the solid line indicates the data accumulation amount Dsb in the buffer 12b, and the alternate long and short dash line indicates the data accumulation amount based on the set transfer rate Rtb.

As shown in FIG. 5, at time t0, the transfer control unit 25 starts data transfer (denoted as “A1” in the drawing) to the buffer 12a, as in the above operation example.
At time t1 when the data transfer A1 to the buffer 12a is completed, the buffer 12b does not store data for the division threshold value Bib. Therefore, at time t1, the divided transfer control unit 23b does not output the transfer instruction Tbb.

  On the other hand, the division transfer control unit 23a outputs a transfer instruction Tba. The data accumulation amount Dsb at time t1 is larger than the data accumulation amount Dsb at time t0. Therefore, the division size Bsa at time t1 is smaller than the division size Bsa at time t0. Therefore, the data transfer A2 based on the division size Bsa calculated at time t1 ends in a shorter period than the data transfer A0 based on the division size Bsa calculated at time t0.

  At the time t2 when the data transfer A2 to the buffer 12a is completed, the buffer 12b does not store data for the division threshold value Bib. Therefore, at time t1, the divided transfer control unit 23b does not output the transfer instruction Tbb. Similarly to time t1, the division transfer control unit 23a outputs a transfer instruction Tba including a division size Bsa smaller than the division size Bsa at the time t1. As a result, the transfer control unit 25 performs data transfer A3 corresponding to the buffer 12a.

  At time t3, the data accumulation amount Dsb in the buffer 12b becomes larger than the threshold value Bib. Then, at time t4 when the data transfer A3 to the buffer 12a is completed, the divided transfer control units 23a and 23b output the transfer instructions Tba and Tbb, respectively, and the arbitrating unit 24 corresponds to the buffer 12b based on the arbitration result. A transfer instruction Tbs corresponding to the transfer instruction Tbb is output. As a result, the transfer control unit 25 performs data transfer B1 corresponding to the buffer 12b.

  As described above, when the transfer rate for transferring data from the device 11b to the buffer 12b is lower than the transfer rate Rtb set in the control unit 22, the data transfer of the other buffers 12a is repeatedly performed. Therefore, for example, as compared with the case where data transfer to the buffers 12a and 12b is alternately performed, the data transfer of the buffer 12a is not waited, and the time required for the data transfer of the buffer 12a can be shortened.

(Third operation example)
In this operation example, the transfer rate (transfer rate) for transferring data from the device 11b to the buffer 12b is higher than the set transfer rate Rtb. In FIG. 6, the solid line indicates the data accumulation amount Dsb in the buffer 12b, and the alternate long and short dash line indicates the data accumulation amount based on the set transfer rate Rtb. Therefore, at the time t2 when the transfer (“A1”) to the buffer 12a is completed, the buffer 12b stores data of an amount equal to or larger than the threshold value Bib.

As shown in FIG. 6, at time t0, as in the operation example shown in FIG. 4, the transfer control unit 25 starts data transfer to the buffer 12a (denoted as “A1” in the figure).
At time t1 when the data transfer A1 to the buffer 12a is completed, the buffer 12b stores data that is equal to or greater than the division threshold value Bib. Therefore, at time t1, the divided transfer control units 23a and 23b output transfer instructions Tba and Tbb, respectively, and the arbitration unit 24, based on the arbitration result, transfers instruction Tbs corresponding to the transfer instruction Tbb corresponding to the buffer 12b. Is output. As a result, the transfer control unit 25 performs data transfer B1 corresponding to the buffer 12b.

  At time t2 when the data transfer B1 corresponding to the buffer 12b ends, the division size calculation unit 21 calculates the division sizes Bsa and Bsb based on the data accumulation amounts Dsa and Dsb of both the buffers 12a and 12b, respectively. At this time, the data accumulation amount Dsb in the buffer 12b is approximately the same as the data accumulation amount Dsb at time t0. Further, the data accumulation amount Dsb at this time is larger than the data accumulation amount Dsb at time t2 shown in FIG. Therefore, the division size calculation unit 21 calculates a division size Bsa having a smaller value than the division size Bsa at time t2 shown in FIG. Then, the transfer control unit 25 starts data transfer A2 of the transfer size JTs (divided size Bsa) to the buffer 12a.

  Similarly to the data transfer A1, at the time t3 when the data transfer A2 is completed, the buffer 12b stores data equal to or greater than the division threshold value Bib. Therefore, at time t1, the divided transfer control units 23a and 23b output transfer instructions Tba and Tbb, respectively, and the arbitration unit 24, based on the arbitration result, transfers instruction Tbs corresponding to the transfer instruction Tbb corresponding to the buffer 12b. Is output. Thereby, the transfer control unit 25 performs the data transfer B2 corresponding to the buffer 12b.

  Thus, when the transfer rate for transferring data from the device 11b to the buffer 12b is faster than the transfer rate Rtb set in the control unit 22, the data when the data transfer for the division size Bsb in the buffer 12b is completed. The accumulation amount Dsb is larger than when the transfer rate is equal to or less than the transfer rate Rtb. Therefore, the time until the data for the threshold value Bib is accumulated in the buffer 12b is short, and the division size Bsa for the buffer 12a is small. Therefore, the waiting time for data transfer in the buffer 12b can be shortened.

  Further, as in the second and third operation examples, the division size calculation unit 21 calculates the division sizes Bsa and Bsb of the buffers 12a and 12b according to the data accumulation amounts Dsa and Dsb of the buffers 12a and 12b. To do. The data accumulation amounts Dsa and Dsb correspond to the transfer speed in the transfer for storing data in the buffers 12a and 12b. Accordingly, the division size calculation unit 21 calculates the division sizes Bsa and Bsb of the buffers 12a and 12b according to the actual transfer rate. For this reason, even if the set values (transfer rates Rta, Rtb) and the transfer rate are different, such as variations among models or setting errors, the divided sizes of the buffers 12a, 12b according to the transfer rate. By calculating Bsa and Bsb, the waiting time for data transfer can be shortened.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The division size calculation unit 21 calculates the division sizes Bsa and Bsb of the buffers 12a and 12b based on the data accumulation amounts of the other buffers. For example, based on the data storage amount Dsb of the buffer 12b, the data storage time Tpb until data of the threshold value Bib or more is stored in the buffer 12b is predicted, and transferred from the buffer 12a according to the data storage time Tpb. The data division size Bsa is calculated. Therefore, when the data transfer to the buffer 12a is completed, the data transfer to the buffer 12b is possible, so that the data transfer to the buffer 12b can be started. For this reason, the waiting time for data transfer in the buffer 12b can be shortened.

  (2) Based on the data storage amount Dsb of the buffer 12b, the data storage time Tpb until data of the threshold value Bib or more is stored in the buffer 12b is predicted, and transferred from the buffer 12a according to the data storage time Tpb. The division size Bsa of the data to be calculated is calculated. The smaller the data accumulation amount Dsb in the buffer 12b, the larger the division size Bsa. Therefore, the data in the buffer 12a can be transferred together by one header, and the overhead in data transfer can be reduced compared to the case where the data is divided into a predetermined size and transferred in multiple times.

  (3) When the transfer rate for transferring data from the device 11b to the buffer 12b is slower than the transfer rate Rtb set in the control unit 22, the data transfer of the other buffer 12a is repeatedly performed. Therefore, for example, as compared with the case where data transfer to the buffers 12a and 12b is alternately performed, the data transfer of the buffer 12a is not waited, and the time required for the data transfer of the buffer 12a can be shortened.

  (4) When the transfer rate at which data is transferred from the device 11b to the buffer 12b is faster than the transfer rate Rtb set in the control unit 22, data storage when data transfer for the division size Bsb in the buffer 12b is completed The amount Dsb is larger than when the transfer rate is equal to or less than the transfer rate Rtb. Therefore, the time until the data for the threshold value Bib is accumulated in the buffer 12b is short, and the division size Bsa for the buffer 12a is small. Therefore, the waiting time for data transfer in the buffer 12b can be shortened.

  (5) The division size calculation unit 21 calculates the division sizes Bsa and Bsb of the buffers 12a and 12b according to the data accumulation amounts Dsa and Dsb of the buffers 12a and 12b. The data accumulation amounts Dsa and Dsb correspond to the transfer speed in the transfer for storing data in the buffers 12a and 12b. Accordingly, the division size calculation unit 21 calculates the division sizes Bsa and Bsb of the buffers 12a and 12b according to the actual transfer rate. For this reason, even if the set values (transfer rates Rta, Rtb) and the transfer rate are different, such as variations among models or setting errors, the divided sizes of the buffers 12a, 12b according to the transfer rate. By calculating Bsa and Bsb, the waiting time for data transfer can be shortened.

In addition, you may implement each said embodiment in the following aspects.
The above embodiment is embodied in the data transfer device 20 that transfers data from the two devices 11a and 11b to the one device 14, but the data transfer device transfers data from three or more devices to one device. It may be embodied. For example, as shown in FIG. 7, three buffers 12a, 12b, and 12c are connected to the data bus 13 for the three devices 11a, 11b, and 11c. The data transfer device 50 is configured according to the number of buffers 12a to 12c. That is, the data transfer device 50 includes the buffers 12a. 12b. 12c includes a division size calculation unit 51 that calculates division sizes Bsa, Bsb, and Bsc according to the data storage amounts Dsa, Dsb, and Dsc. The division sizes Bsa, Bsb, and Bsc are supplied to the division transfer control units 53a, 53b, and 53c, respectively. Is done.

  The control unit 52 supplies threshold values Bia, Bib, Bic and transfer rates Rta, Rtb, Rtc corresponding to the buffers 12a, 12b, 12c, and the transfer rate Rt0 of the bus 13 to the division size calculation unit 51, respectively. Further, the control unit 52 supplies transfer instructions Tsa, Tsb, and Tsc to the corresponding divided transfer control units 53a, 53b, and 53c, respectively.

  The division transfer control unit 53a generates a transfer instruction Tba based on the transfer instruction Tsa, the data accumulation amount Dsa, and the division size Bsa. The division transfer control unit 53b generates a transfer instruction Tbb based on the transfer instruction Tsb, the data accumulation amount Dsb, and the division size Bsb. The division transfer control unit 53c generates a transfer instruction Tbc based on the transfer instruction Tsc, the data accumulation amount Dsc, and the division size Bsc.

  The arbitrating unit 24 arbitrates the transfer instructions Tsa to Tsc output from the divided transfer control units 53a to 53c and outputs the transfer instruction Tbs. The transfer control unit 55 controls data transfer to each of the buffers 12a to 12c based on the transfer instruction Tbs.

  As illustrated in FIG. 8, the division size calculation unit 51 includes three time prediction units 61a to 61c corresponding to the buffers 12a to 12c. The time prediction unit 61a calculates the data accumulation time Tpa based on the transfer rate Rta, the threshold Bia, and the data accumulation amount Dsa corresponding to the buffer 12a. Similarly, the time prediction unit 61b calculates the data accumulation time Tpb based on the transfer rate Rtb, threshold Bib, and data accumulation amount Dsb corresponding to the buffer 12b. The time prediction unit 61c calculates the data accumulation time Tpc based on the transfer rate Rtc, the threshold value Bic, and the data accumulation amount Dsc corresponding to the buffer 12c.

  The size converter 62a converts the data accumulation time Tpa to the predicted size Psa based on the transfer rate Rt0 of the data bus 13. Similarly, the size converter 62b converts the data accumulation time Tpb to the predicted size Psb based on the transfer rate Rt0 of the data bus 13. The size converter 62c converts the data storage time Tpc into the predicted size Psc based on the transfer rate Rt0 of the data bus 13.

  The selection unit 63 generates predicted sizes P2a to P2c for the clip processing units 64a to 64c based on the predicted sizes Psa to Psc output from the size conversion units 62a to 62c. The clip processing units 64a to 64c correspond to the buffers 12a to 12c, respectively. The selection unit 63 selects one of the two non-corresponding division sizes for the clip processing units 64a to 64c corresponding to the buffers 12a to 12c, and outputs the selected division size.

  For example, the selection unit 63 selects a smaller divided size from the two predicted sizes Psb and Psc corresponding to the buffers 12b and 12c for the clip processing unit 64a, and predicts the same value as the selected divided size. The size P2a is output. Similarly, the selection unit 63 selects a smaller division size from the two predicted sizes Psa and Psc corresponding to the buffers 12a and 12c for the clip processing unit 64b, and is equal to the value of the selected division size. The predicted size P2b is output. Further, the selection unit 63 selects a smaller division size from the two prediction sizes Psa and Psb corresponding to the buffers 12a and 12b, and predicts the clip processing unit 64c equal to the selected division size value. The size P2c is output.

  The clip processing unit 64a outputs a divided size Bsa generated by clipping the predicted size P2a based on the upper limit value Bamx and the lower limit value Bamn supplied from the register 65. Similarly, the clip processing unit 64b outputs a divided size Bsb generated by clipping the predicted size P2b based on the upper limit value Bbmx and the lower limit value Bbmn supplied from the register 65. The clip processing unit 64c outputs the divided size Bsc generated by clipping the predicted size P2c based on the upper limit value Bcmx and the lower limit value Bcmn supplied from the register 65.

  As described above, by changing the division size when the data stored in the buffers 12a to 12c is transferred to the device 14, the waiting time for the transfer can be shortened as in the above embodiment.

  The selection unit 63 may be configured to select and output one of the two divided sizes of the unsupported buffer to each of the clip processing units 64a to 64c in accordance with the set priority order. In FIG. 8, the selection unit 63 is connected between the size conversion units 62a to 62c and the clip processing units 64a to 64c, but the selection unit 63 is connected to the time prediction units 61a to 61c and the size conversion units 62a to 62c. You may make it connect between.

  In the above embodiment, the transfer rates Rta and Rtb from the communication devices 11a and 11b to the buffers 12a and 12b output from the control unit 22 to the division size calculation unit 21 are fixed. A configuration in which the rates Rta and Rtb are appropriately changed may be adopted.

  In the above embodiment, the configuration is adopted in which the communication devices 11a and 11b (each buffer 12a and 12b) have the same transfer destination. However, for example, the communication devices 11a and 11b (each buffer 12a and 12b) Different transfer destinations may be used. In short, if the communication devices 11a and 11b (buffers 12a and 12b) are configured to use a common (shared) data bus 13 when transferring data to the target device, the present invention is applied. Can do.

  In the above embodiment, the data transfer is performed from the communication device 11a and the communication device 11b to the target device 14 via the data bus 13, that is, the transfer direction of the data transfer is set to one direction. Not limited to this. For example, when the data transfer is configured to enable bidirectional data transfer between the communication devices 11a and 11b and the target device 14, the division size for each buffer is changed by the data transfer device 20 (division size calculation unit 21). Thus, even if the configuration allows bidirectional data transfer, the same effect as the effect (1) can be obtained.

  In the above embodiment, the transfer rates Rta and Rtb between the buffers 12a and 12b and the communication devices 11a and 11b are set in advance, but the present invention is not limited to this. For example, a configuration may be adopted in which the transfer rate between the buffers 12a and 12b and the communication devices 11a and 11b is measured at predetermined timings or at arbitrary timings, and the measured values measured are used as the transfer rates Rta and Rtb.

  A frequency of a clock signal (for example, a clock signal for operating a transmission circuit of the communication devices 11a and 11b) used when transferring data from the communication devices 11a and 11b to the buffers 12a and 12b is set to a transfer rate Rta and Rtb. You may make it use as. Similarly, the frequency of the clock signal may be used for the transfer rate Rt0 of the data bus 13.

  In the above embodiment, the upper limit values Bamx and Bbmx and the lower limit values Bamn and Bbmn of the division size for each buffer 12a and 12b are set. However, only one of the configurations, or the upper limit value and the lower limit value are set. It is good also as a structure which does not set both.

  In the above embodiment, the size of data to be divided (divided size Bsa, Bsb) is changed in accordance with the data accumulation amount Dsa, Dsb of the data accumulated in the buffers 12a, 12b. , 12b, the size of data to be divided may be changed according to the free capacity.

  Although not particularly mentioned in the above embodiment, the data bus 13 is any of an internal bus inside the CPU, an external bus outside the CPU, and an expansion bus used when adding an expansion card or the like. May be. In short, any device may be used as long as a plurality of devices are connected to one transfer path (bus), and these devices transfer data to the respective transfer target devices via the transfer path. The data bus 13 only needs to be able to transfer data from the buffers 12a and 12b to the device 14, and the communication form such as wireless communication and wired communication, and the configuration form such as serial bus and parallel bus are not limited.

The following notes are disclosed regarding the above embodiments.
(Appendix 1)
A data transfer device that transfers data stored in each of a plurality of buffers to a transfer destination via a single bus to which the plurality of buffers are connected,
A division size calculation unit that calculates a division size based on the data accumulation amount of the plurality of buffers;
A plurality of division transfer control units that output a buffer transfer instruction corresponding to the plurality of buffers and corresponding to the division size and the data accumulation amount;
A transfer control unit for transferring data from the buffer to the transfer destination in response to the transfer instruction;
A data transfer device including:
(Appendix 2)
The data transfer apparatus according to appendix 1, wherein the division size calculation unit calculates a division size for the plurality of buffers every time data transfer for the division size is completed.
(Appendix 3)
The data transfer apparatus according to appendix 1 or 2, wherein the division size calculation unit calculates the division sizes of the plurality of buffers based on the data accumulation amount of buffers other than the calculation target.
(Appendix 4)
The division size calculation unit
A plurality of time prediction units for calculating respective predicted times until the next transfer request is issued based on the data accumulation amounts of the plurality of buffers;
A plurality of size conversion units that respectively convert a plurality of the predicted times into a plurality of the divided sizes based on a transfer rate of the bus;
The data transfer device according to any one of Appendices 1 to 3, characterized by comprising:
(Appendix 5)
The additional size 4 is characterized in that the division size calculation unit includes a plurality of clip processing units that respectively clip the plurality of division sizes based on an upper limit value and a lower limit value corresponding to each of the plurality of buffers. The data transfer device described.
(Appendix 6)
At least three of the buffers are connected to the bus,
Any one of Supplementary notes 1 to 5, wherein the division size calculation unit calculates a division size of the plurality of buffers based on a minimum prediction time of prediction times of buffers other than the calculation target. A data transfer apparatus according to claim 1.
(Appendix 7)
The data transfer apparatus according to appendix 4, wherein the time prediction unit calculates the prediction time based on a data accumulation amount, a transfer rate, and a transfer start threshold value of the corresponding buffer.
(Appendix 8)
A data transfer method for transferring data stored in each of a plurality of buffers to a transfer destination via a single bus to which the plurality of buffers are connected,
A division size is respectively calculated based on the data accumulation amount of the plurality of buffers, a transfer instruction for the buffer corresponding to the plurality of buffers is generated according to the division size and the data accumulation amount, and the transfer instruction A data transfer method of transferring data from the buffer to the transfer destination in response to

12a to 12c buffer 13 data bus 14 device (transfer destination)
20, 50 Data transfer device 21, 51 Division size calculation unit 23a, 23b, 53a to 53c Division transfer control unit 25, 55 Transfer control unit 31a, 31b, 61a to 61c Time prediction unit 32a, 32b, 62a to 62c Size conversion unit 33a, 33b Clip processing unit Bia, Bib threshold (transfer start threshold)
Tpa, Tpb Data accumulation time (estimated time)
Dsa, Dsb, Dsc Data accumulation amount Rta, Rtb, Rtc Transfer rate Rt0 Transfer rate Bsa, Bsb, Bsc Division size Bamx, Bbmx Upper limit value Bamn, Bbmn Lower limit value

Claims (4)

A data transfer device that transfers data stored in each of a plurality of buffers to a transfer destination via a single bus to which the plurality of buffers are connected,
A division size calculation unit that calculates a division size based on the data accumulation amount of the plurality of buffers;
A plurality of division transfer control units that output a buffer transfer instruction corresponding to the plurality of buffers and corresponding to the division size and the data accumulation amount;
See containing and a transfer control unit that transfers the data to the transfer destination from the buffer in response to the transfer instruction,
The division size calculation unit
A plurality of time prediction units for calculating respective predicted times until the next transfer request is issued based on the data accumulation amounts of the plurality of buffers;
A plurality of size conversion units that respectively convert a plurality of the predicted times into a plurality of the divided sizes based on a transfer rate of the bus;
A data transfer device comprising:   The data transfer apparatus according to claim 1, wherein the division size calculation unit calculates a division size for the plurality of buffers every time data transfer for the division size is completed.   The data transfer apparatus according to claim 1, wherein the division size calculation unit calculates a division size of each of the plurality of buffers based on a data accumulation amount of a buffer other than the calculation target. A data transfer method for transferring data stored in each of a plurality of buffers to a transfer destination via a single bus to which the plurality of buffers are connected,
Calculate the estimated time until the next transfer request is issued based on the data accumulation amount of the plurality of buffers , respectively, and convert the plurality of estimated times into a plurality of division sizes based on the bus transfer rate, respectively. A buffer transfer instruction corresponding to the plurality of buffers, corresponding to the division size and the data accumulation amount, and transferring data from the buffer to the transfer destination according to the transfer instruction; Transfer method.

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