Decade and a half ago there was PacketShader, which used usermode networking+GPUs to do packet routing. It was a thrilling time. I thought this kind of effort to integrate off-the-shelf hardware and open source software-defined-networking (SDN) was only going to build and amplify. We do have some great SDN but remains a fairly niche world that stays largely behind the scenes. https://shader.kaist.edu/packetshader/index.html
I wish someone would take up this effort again. It'd be awesome to see VPP or someone target offload to GPUs again. It feels like there's a ton of optimization we could do today based around PCI-P2P, where the network card could DMA direct to the GPU and back out without having to transit main-memory/the CPU at all; lower latency & very efficient. It's a long leap & long hope, but I very much dream that CXL eventually brings us closer to that "disaggregated rack" model where a less host-based fabric starts disrupting architecture, create more deeply connected systems.
That said, just dropping down an fpga right on the nic is probably/definitely a smarter move. Seems like a bunch of hyperscaler do this. Unclear how much traction Marvell/Nvidia get from BlueField being on their boxes but it's there. Actually using the fpga is hard of course. Xilinx/AMD have a track record of kicking out some open source projects that seem interesting but don't seem to have any follow through. Nanotube being an XDP offload engine seemed brilliant, like a sure win. https://github.com/Xilinx/nanotube and https://github.com/Xilinx/open-nic .
I've been exactly thinking about it this way for a long time. Actually once we're able to push computation down into our disk drives, I wouldn't be surprised if these "Disk Shaders" will be written in eBPF.
Totally sibling comment confirms it already exists! I hope that the 'shader' name sticks too! I find the idea of a shader has a very appropriate shape for tiny-program-embedded-in-specific-context so it seems perfect from a hacker POV!
I have a VFX(Houdini now, RSL shaders etc earlier) and openCL-dabbling and demoscene-lurking background, based on which I think I prefer 'shader' to 'kernel', that's what OpenCL calls them.. but that conflicts with the name of like, 'the OS kernel' at least somewhat..
This analogy works well when trying to describe how eBPF is used for network applications. The eBPF scripts are "packet shaders" - like a "pixel shaders" they are executed for every packet independently and can modify attributes and/or payload according to a certain algorithm.
The name “shader” screwed me up for so long. But once I better understood what they really are I think they’re incredibly powerful. “Kernel shader” is amazing.
