Large packets, I'm not sure. For a long time, you've been able to attach a file descriptor (e.g. one end of a pipe) to a message, and then send bulk data over the file descriptor.
My understanding of this whole thing was that most of the car companies thought they should try using linux for their console / entertainment / etc systems. Electrical and mechanical engineers seem to all only use windows and not know anything about linux, so they asked themselves "what's the bus on linux?" and found D-bus, the desktop bus used by desktop environments and utilities, for a handful of messages a minute.
They used it to send frequent sensor data to all sorts of services that might be interested, like digital gauges, sound distribution, etc. They didn't realize that there are lots of good low-level IPC mechanisms available on linux, and they should have probably used 0mq, or a scheme based on unix sockets with filesystem permissions based access control, etc.
Anyway, they realized that D-bus had way too much overhead, and instead of porting to some other IPC, got to work accelerating D-bus with additional kernel functionality, such as the AF_BUS which was rejected by the linux networking maintainers. (Though that was probably a better idea than kdbus.)
How exactly GregKH got into this project, I'm not entirely sure. He is relatively friendly with the systemd developers. He's paid by the Linux Foundation, and many of those car companies are members of the Linux Consortium, or something like that, I think. I dunno. Apparently a lot of people used D-bus accidentally, and now the thing to do is make the kernel make it faster.
My understanding of this whole thing was that most of the car companies thought they should try using linux for their console / entertainment / etc systems. Electrical and mechanical engineers seem to all only use windows and not know anything about linux, so they asked themselves "what's the bus on linux?" and found D-bus, the desktop bus used by desktop environments and utilities, for a handful of messages a minute.
They used it to send frequent sensor data to all sorts of services that might be interested, like digital gauges, sound distribution, etc. They didn't realize that there are lots of good low-level IPC mechanisms available on linux, and they should have probably used 0mq, or a scheme based on unix sockets with filesystem permissions based access control, etc.
Anyway, they realized that D-bus had way too much overhead, and instead of porting to some other IPC, got to work accelerating D-bus with additional kernel functionality, such as the AF_BUS which was rejected by the linux networking maintainers. (Though that was probably a better idea than kdbus.)
How exactly GregKH got into this project, I'm not entirely sure. He is relatively friendly with the systemd developers. He's paid by the Linux Foundation, and many of those car companies are members of the Linux Consortium, or something like that, I think. I dunno. Apparently a lot of people used D-bus accidentally, and now the thing to do is make the kernel make it faster.