undefined

points

[-]

> it’s not even clear if it can saturate a gigabit

If that's the case then it's not the CPU's fault. I can't open the linked site but assuming it's really the same as a BPI-F3 i.e. a SpacemiT K1 chip, that can do 2.8 GB/sec on large RAM to RAM memcpy using a CPU core i.e. 44 Gbps total, 22 Gbps each read and write. Plus I assume it's got DMA so no need to involve the CPU anyway.

Here is a test I ran in April 2025 on a Sipeed LicheePi 3A same chip).

https://hoult.org/K1_memcpy.txt

> RISC-V is quite wimpy this far

The new K3 chip from the same manufacturer does 8.7 GB/s RAM to RAM memcpy using a dual issue in-order A100 ("AI") core, just over 3x faster.

Sure this pales in comparison to recent Apple / Intel / AMD but it's a lot faster than home networking.

by tredre312 hours ago|

parent|

[-]

Although your benchmark is interesting, I don't think it's very relevant here. In my experience, you'll saturate the CPU through packet decoding, routing, and firewalling long before memory becomes a bottleneck.

That's why all network SoCs have hardware to accelerate such thing, otherwise in software alone they can barely handle simple routing at a few hundred mbps.

That chip doesn't seem to have that: https://cdn-resource.spacemit.com/file/chip/K1/K1_datasheet_...

by Veserv9 hours ago|

parent|

[-]

1 Gb/s is only ~100,000 packets/s at standard MTU. You literally get 10 us/packet which is a eternity. Normal fast-path router operation only really needs to consider the header of <100 bytes/packet, so you are getting ~100 ns of compute per byte of considered data and on even a 1 Ghz processor you are getting over 100 instructions per byte of considered data. Failure to achieve a measly 1 Gb/s really says more about those software implementations than it says anything about the impossibility or difficulty of the problem.

by crote3 hours ago|

parent|

[-]

Not all packets are 1500 bytes.

by throwaway2744814 hours ago|

prev|

[-]

> The one benefit is that it doesn’t have Intel IME/AMT, AMD PSP or ARM TrustZone backdoors built-in, but I would be extremely surprised if the Chinese SpaceMiT CPU didn’t have Chinese backdoors of its own.

That seems worth paying for. How could china hurt me more than my own government?

by fmajid5 hours ago|

parent|

[-]

Yes, you have to decide in your threat model which is worse. There are people who’ve built entire systems on RISC-V FPGA soft cores like Bunnie Huang’s Precursor, but none fast enough to serve as a router.

by HDBaseT12 hours ago|

parent|

prev|

[-]

Yep. It's crazy how effective the US Gov has made it seem like China are the bad guys, when it was US/Israel all along.

by Melatonic14 hours ago|

prev|

[-]

Exactly - seems like the only big thing going for it