You can play with NIC interrupt coalescing settings to keep them under
control (I don't know how in FreeBSD, but in Linux you would do that with
e.g. "ethtool -C rx-usecs 100").
As written in the last line of netmap(4), you must disable all the
offloadings when playing with netmap physical ports.

By the way, there is a person working on adding some offloading support to
netmap, but this is still in progress and it is not even in the netmap
github yet.

Cheers,
  Vincenzo

2017-06-06 11:59 GMT+02:00 Harry Schmalzbauer <[email protected]>:

>  Bezüglich Harry Schmalzbauer's Nachricht vom 05.06.2017 20:25 (localtime):
> > Bezüglich Vincenzo Maffione's Nachricht vom 05.06.2017 16:06 (localtime):
> >
> …
> > First quick test shows you're right and this tiny diff solves a decent
> > share of my (ESXi-replacing) problems:
> >
> > --- src/sys/net/if_vlan.c.orig  2017-06-05 17:39:27.770574000 +0200
> > +++ src/sys/net/if_vlan.c       2017-06-05 17:39:21.550278000 +0200
> > @@ -1234,7 +1234,7 @@
> >         if_inc_counter(ifv->ifv_ifp, IFCOUNTER_IPACKETS, 1);
> >
> >         /* Pass it back through the parent's input routine. */
> > -       (*ifp->if_input)(ifv->ifv_ifp, m);
> > +       (*ifv->ifv_ifp->if_input)(ifv->ifv_ifp, m);
> >  }
> >
> >  static int
> >
> > Will do real-world tests tommorrow.
>
> To share my observations:
>
> Attaching if_vlan(4) to vale(4) works with the above modification, as
> long as vlanhwtag is _not_ disabled, at least with igb(4) and (em4).
> Having other offloadings enabled or disabled (regardless if it's on
> parent or vlan-clone) doesn't matter, disabling vlanhwtag on the parent
> leads to congested parent if there's mor etraffic than console... I
> haven't done any tracking if it's caused by TCP windows scaling e.g. nor
> tried to ask the code, because I do want vlanhwtagging enabled and
> that's what works so far :-)
> This is also true for if_vlan(4) interfaces which have if_lagg(0) as
> parent, and also for both types of vale(4) attaching, hoststack-detached
> (-a) or hoststack-attached (-h).
> So far very nice :-)
>
> But there's a interrupt multiplication noticeable (at the host).
>
> My simple NFS-copying test causes ~10ki/s at one igb(4) queue when
> invoked on the host, with mtu 1500.
> Same invocation in the guest, with vlan-vale setup, causes 30ki/s
> average (with high discrepancy, 20-40k).
>
> Might it be possible that if_vlan(4) influences interrupt moderation
> capabilities?
>
> Vincenzo, thanks for your answers to my questions, which I read during
> writing of this - stripping them here.
>
> -harry
>



-- 
Vincenzo Maffione
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