Continuous SPI with PYNQ-Z2

Hi all,
I am currently using SPI as master with PYNQ-Z2. Although the communication is great now, I am wondering if I can speed it up even more by making the data transfer continuously.
To be more accurate, as shown in the figure below,

I am trying to send/receive 6 16bit data at once, however, there is a time delay for about 19.2 µs between every data transfer.
BTW, I have done it successfully in F28335 DSP board by writing into Tx FIFO first and then read them out together, but I did not find the same way to do it in PYNQ-Z2 board.

Please guide me how to write into Tx FIFO or any other ways that can do the same trick.

My setting for SPI IP is as the following figure:

Please let me know if more information is needed, thanks!