Hi @Eyal ,
I just did a quick test and I am getting 2.0ms ping time when voxl2 cpu is in perf mode, and about 2.5ms when in auto mode. VOXL2 is idle.
the NCM networking feature works concurrently with ADB, which is great and we also have some scripts to set up NAT if you need your voxl2 to actually use the Linux host as a "router" to access outside world. that is easy to set up as well (requires some routing changes on the linux host).
In terms of real-time streaming, it is definitely adequate for image / video streaming to a Linux host. In fact, this option is my personal favorite way of connecting to Voxl2 while developing / testing cameras and viewing multiple streams in voxl-portal. Voxl-portal uses jpeg compression, which is a lot less efficient than h264/h265 and with the NCM connection, i don't have any issues (compared to adb port forwarding, which also allows voxl-portal to work, but is about 10x slower and uses a lot more CPU, you get frame drops in voxl-portal if required bandwidth is higher than 30-50Mbps or so). I am mainly using the USB-NCM feature for development purposes (as opposed to on a flying drone), but i have not found any limitations, at least for the bench testing use case.
In terms of CPU load affecting the speed, i just ran a test stress -c 8 which loads up all 8 cores to 100% and the ping times did not change in perf mode (2.0ms) and in auto mode, the ping times reduced from 2.5ms to 2.0ms because the cpu cores are actually running at faster speeds. I am guessing that all the USB stuff is happening in the kernel at a higher priority, so it's not affected by the user applications (unless the cpu overheats, i supposed). GPU / DSP loads should not have any effect on this, since they are separate hardware.
I also did another test - stream 4 video streams to voxl-portal (live view), which added up to about 100Mbps of network traffic and ping time stayed between 1.5-3.0ms (sometimes lower than 2.0ms).
I have not observed any stability issues related to NCM being active for long periods of time (days). Make sure you are using a high quality USB-C cable (nothing fancy).
Alex
