On Thu, Aug 16, 2012 at 10:38 AM, Марк Коренберг <socketp...@gmail.com> wrote: > On my PC, tap <--> bridge <--> tap networking gives 600 megbit. > > Exactly the same, but -net socket,mcast gives about 1 megbit (!) I do not > understand why. > > In my mind, -net socket,mcast is the same as tap, but ethernet frames are > going in much simplier way: instead of > > qemu1 -> /dev/tun -> kernel/bridge -> /dev/tun -> qemu2 > > in such way: > > qemu1 -> qemu2 > > > Does somebody knows, why -net socket,mcast works so slowly? > > People said, that VDE performace is like TAP. Why not to make same > performace on -net socket,mcast ?
600 -> 1 Mbit/s performance difference is larger than expected. Can you post more details? 1. qemu and Linux kernel versions 2. qemu command-lines for your tap and mcast setups 3. Which benchmark and the command-line to run the test Stefan