[eeks]

> I think using TCP, but I don't recall for sure

It was UDP.

> Which is to say, you're saying "detrimental impact on performance" and yet this seems to be a significant win over BSD sockets.

The point I was trying to drive home is that, while 30% overhead reduction compared to BSD socket is nothing to laugh at, a fully user-space UDP/TCP network stack combined with memory-mapped buffer sharing usually gives performance improvement measured in the "x" and not in the "%".

Now, there is not much in terms of experiment protocol in their material so its very hard to tell. You mention uncompressed video so they could be sending humongous frames, which I doubt as no one ever would send raw frames over the network (that would be several MB per frame for a 720p front camera). But if that is the case then the data copy operation becomes the predominant bottleneck and getting rid of one may justify the improvement. But that is not a realistic scenario.

The more realistic scenario is that they sent compressed delta-frames across the network (H264 or HEIF), which would then considerably reduce the transferred payload size. In that scenario, data copy is not the predominant overhead anymore and 30% overhead reduction is underwhelming, telling me that they still are calling expensive operations like syscalls/uIPC on the critical data path.

[eridius]

According to what they said in the session, they were asking for video frames from the camera and sending them, completely un-interpreted, over the network. The idea being the receiving device could take these frames and handle them exactly the same way as they would handle data coming from the local camera.