Measurement of actual pcie rate

drakonof · 04-03-2020, 06:15 AM

Hi all.

I want to determine the pcie data transfer speed.

For definition of ns which will be used to calculate the pcie rate, I do so:

Code:

tStart = ktime_get_real();
memcpy(probPriv->memFromBar,dataToBar,1024 );
tStop = ktime_get_real();
tRes = ktime_to_ns(ktime_sub(tStop,tStart));

Is it correct?

PC with Debian 10.
Xilinx Artix7 as the pcie card.
Both PC and FPGA pcie are without dma.

Rest parts of the pcie kernel driver work correctly.

smallpond · 04-03-2020, 02:01 PM

pcie data transfer speed can be determined from the lspci command. For example:

Code:

sudo lspci -vvv -s 02:00 |grep LnkCap
                LnkCap: Port #3, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s

drakonof · 04-04-2020, 09:48 AM

Quote:

Originally Posted by smallpond

pcie data transfer speed can be determined from the lspci command. For example:

Code:

sudo lspci -vvv -s 02:00 |grep LnkCap
                LnkCap: Port #3, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s

Thank you for your reply.

I am sorry for my ambiguous question. I meant that I need to know the speed rate of a data transfer at this moment and in these conditions, but not a bandwidth of my pcie.

I thought that it will be clear from code that I had attached.

BW-userx · 04-04-2020, 10:10 AM

yeah Like windows does when its moving files, thunar does this too, you could get there source code and seek out that information to see how they are doing it. it is open source, a great source for learning by reading others code to see how they did it.

mrmazda · 04-04-2020, 07:40 PM

hdparm -tT /dev/nvme0nX won't do what you want?

drakonof · 04-05-2020, 01:18 AM

Quote:

Originally Posted by BW-userx

yeah Like windows does when its moving files, thunar does this too, you could get there source code and seek out that information to see how they are doing it. it is open source, a great source for learning by reading others code to see how they did it.

Thank you. I am not a professional programmer since I develop FPGA devices and unfortunately have had a lack of experience in searching of answers in any code. I think it will be fixed with time.

drakonof · 04-05-2020, 07:40 AM

Quote:

Originally Posted by mrmazda

hdparm -tT /dev/nvme0nX won't do what you want?

Thanks, but I am writing a pcie test in the kernel space, hence I need a C code for that.