Request for Information: Precision Packet Transmission for Periodic Control Traffic

[ycdfwzy]

Hello, I noticed that you are using TSN to control multimedia traffic transmission. I'm interested in using this project to control a robotic arm, where I need to send control packets every 1 millisecond. In this scenario, I would require a mechanism that can accurately control the sending rate to ensure that the control packets are sent at the specified interval. Does this project support this functionality? Thank you!

[frankdjx]

Currently we don't has APIs for this feature. But the ST2110 audio usually is sending at 1ms interval, it's probably we can support such function.

Please also note, the TSN is only available on intel i225 NIC, do you have this NIC? For other NICs, we need use CPU TSC to control the timing, the jitter is object to the kernel scheduler jitter which is around max 100us per our observation, so what accuracy you expected? Will 100us jitter a problem for your case?

[ycdfwzy]

Thanks for your reply.

Please also note, the TSN is only available on intel i225 NIC, do you have this NIC?

We have i210 NIC and i225 NIC.

what accuracy you expected? Will 100us jitter a problem for your case?

We want the jitter to be as small as possible, probably in the worst case <10us or even <1us is acceptable. We have observed that jitter can be as high as 1ms or more on Linux non-real-time kernel and network stack, so we are looking for a viable solution.

[frankdjx]

The accuracy of I225 TSN is around a very great ~10ns.

Do you have a Intel marketing contact? This repo is designed for ST2110 protocol, we need some business justification to arrange the priority since it's a new requirement. The proposal is adding a time option to current UDP stack sendto API and pass the time control info to I225 NIC.

[frankdjx]

CC @gongxiao-intel