Hello,
I have a PCIe FPGA card(card A, Gen 2/Gen 3 x8) which runs well on ASUS P9X79 WS and Z270 WS mother board. This FPGA card performs data acquisition, and DMA data in chained DMA to host memory, and I can acquire data consecutively for virtually infinitely(very long time), the data are all good.
The OS is CentOS 7.3(Kernel 3.10).
However, on a Xeon D1541 mother board(the chipset is a SoC on the CPU I believe), although the PCIe seem to be able to DMA data into host memory, after data analysis, there is PCIe packet lost which happens intermediately. After many testing, it is confirmed this card can only transfer up to several Mega Bytes of data which are all good; after which the data are corrupted; after this the data will be resumed good again and corrupted again. and so on.
I also tested another proven and good PCIe FPGA card(card B)on this D1541 motherboard, as this card B has a larger on-board FIFO(4GB) in FPGA, so I can run for longer data set; but even though, after the 4GB data, the data becomes corrupted.
It gives me the feel that the CPU/PCIe is not able to responding to the DMA transfer "always timely". it can run good for a while, but is not keeping up well after it. that is why I see there is a data loss.
I would like to seek any advice from guru and expert here and see which are the parameters I can fine-tune to resolve the data loss(PCIe packet losing) issue?
Thank you.
Mei Guodong, from Singapore
