4 ms·

That’s llama, which didn’t scale nearly as well in the tests. Assumedly because it’s not optimized yet. RDMA is always going to have lower overhead than Ethern

by MBCook 10mo ago

That’s llama, which didn’t scale nearly as well in the tests. Assumedly because it’s not optimized yet. RDMA is always going to have lower overhead than Ethernet isn’t it?

Neywiny 10mo ago
Possibly RDMA over thunderbolt. But for RoCE (RDMA over converged Ethernet) obviously not because it's sitting on top of Ethernet. Now that could still have a higher throughput when you factor in CPU time to run custom protocols that smart NICs could just DMA instead, but the overhead is still definitively higher
- _zoltan_ 10mo ago
  what do you think "ethernet's overhead" is?
  - Neywiny 10mo ago
    Header and FCS, interpacket gap, and preamble. What do you think "Ethernet overhead" is?
    - _zoltan_ 10mo ago
      I've meant in usec, sorry if that wasn't clear, given that the discussion that I've replied was about rpc latency.
      - Neywiny 10mo ago
        That's a very nebulous metric. Usec of overhead depends on a lot of runtime things and a lot of hardware options and design that I'm just not privy to