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Comment by hinkley | Hacker News Reader

If we could get an off the shelf SOC that's powerful enough to manage a PCIe daughter card, that would make me so happy.

Software defined radio, offloaded eBPF, RAID controllers, are just the most obvious compute peripherals but there are a million others that could exist but don't.

edit: acronym typo

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Rock 5B [1] or any other board running on a RK33588

[1] https://wiki.radxa.com/Rock5/hardware/5b

You have 4x lanes of Pcie 3.0 and the Rock 5b has 2.5gb Ethernet too.

Software support isn't there yet but it's slowly getting better.

I would expect the internal bandwidth of a daughter card to need to be upward of 2x the PCIe lanes that it supports to the motherboard.

For instance a RAID card has to accept data from the motherboard and write it to the disks as fast as the disks allow.

We could do a PCIe card, but what I'm hoping for is to be able to dig ourselves out of the binary blob problem with have where Linux barely controls the actual hardware these days, and security concerns aren't something you can volunteer to fix. Our peripherals are pretending not to be computers but really they are and have been for some time.

If vendors aren't going to give us Open hardware, which it seems is never going to happen, then 'general purpose' expansion cards might be a forcing function.

We maybe come from different worlds but I have soc == security operations centre and ebnf == extended Backus-Naur form.

What are these in the context of your comment, though?

SoC in this case is a system on a chip - despite the "a" it's abbreviated the same

https://en.m.wikipedia.org/wiki/System_on_a_chip

Probably see SBC's used more as a term for them than SoC's as they incorporate more than just the die (imho)

Well, except once you have a PCIe daughter card it's no longer an SBC; you have at least two boards right there.

No but it is before you add one, so that's the best place to start.

Not necessarily. If this is based on a CM4 (almost certainly), then there's no SBC at all since the CM4 is a SoM.

Yes and there are dozens more than just the CM4 that have it embedded... on a single system board.

CaPiTaLiZaTiOn

You're right. SOC versus SoC. The capitalization is important.

Not them but I would assumes SoC is System on (a) Chip, and ebnf may be a typo of eBPF (in the context of eBPF offloading to perform filtering on the NIC [1])

[1] https://www.netronome.com/media/documents/eBPF_HW_OFFLOAD_HN...

Offloaded eBNF? You must be dealing with extremely large grammars if you need dedicated hardware to manage it :0

I think they mean a NIC that you can offload eBPF programs onto.

Exactly.

Aren't there quite a few already? People have been powering eGPU's with them.

CM4 supports it, although its just 1x and PCIe 2.0

The RPi4 SoC has a lot constraints wrt PCIe and frankly appears to not implement the PCIe spec completely or correctly. A lot PCIe devices simply don't work with it.

After reading this thread a few times I realized you're asking for an SoC that is a daughter card, aka a DPU.

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