Using the new bridges of FreeBSD 15

(blog.feld.me)

58 points | by vermaden 4 hours ago

5 comments

  • j16sdiz 32 minutes ago
    Why sudden surge of FreeBSD-related posts?

    Did anything special or new happened on FreeBSD land?

  • ggm 3 hours ago
    When this settles down, I look forward to all of jail/iojail, Sylve, Bastille, Bhyve documenting this in a mutually consistent manner. As it stands, I have managed to completely knot my brain over the abstractions, what is happening. It's me, not the systems, but I think there is a little bit of "meh, I understand it, so it must be obvious to anyone smart" going on, and alas, I am not smart, and I get confused easily.

    I'm in bastille atm, but have been in all of them and TrueNAS core. and libvirt over on the other unix.

  • shashasha2 4 hours ago
    Bhyve bridges are inefficient: every packet traverses NIC → CPU → bridge → VM, adding unnecessary copies that kill throughput. Switching to SR-IOV eliminated that overhead and I saturated the 10 GbE link.
    • Veserv 3 hours ago
      I do not see how that follows. Memory bandwidth is measured in the hundreds of Gb/s. You can issue tens of unnecessary full memory copies before you bottleneck at a paltry 10 Gb/s.

      It is much more likely there is something else terribly wrong in a network stack if it can not even drive a measly 10 Gb/s.

      • stingraycharles 3 hours ago
        That assumes memory bandwidth is the issue, and not latency and/or CPU.
    • kev009 25 minutes ago
      It would benefit from a batching mechanism.
    • assimpleaspossi 4 hours ago
      You used the new optimized bridges on FreeBSD 15?
    • gigatexal 3 hours ago
      On Linux?
  • waynesonfire 2 hours ago
    > -tso4 -tso6 -vlanhwfilter -vlanmtu -vlanhwtso -vlanhwtag -vlanhwcsum -lro

    Whys the author disabling tso and lro? Whats the motivation?

    I'm not familiar with the other flags.

    • kev009 27 minutes ago
      People found this worked in the past and it gets copied around. There is no reason to disable some of this. Bridge will automatically disable LRO and find the common set of other offloads. TSO is not useful for a bridged guest.
    • j16sdiz 29 minutes ago
      Looks like TSO does not support VLAN. Not sure about lro.
  • bzmrgonz 2 hours ago
    I for one welcome and applaud any progress on the bsd front,and this seems to be huge.