Date: Wed, 22 Nov 2017 09:39:15 +0100 From: Harry Schmalzbauer <freebsd@omnilan.de> To: Vincenzo Maffione <v.maffione@gmail.com> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Giuseppe Lettieri <g.lettieri@iet.unipi.it> Subject: Re: netmap/vale periodic deadlock Message-ID: <5A1537B3.9030603@omnilan.de> In-Reply-To: <CA%2B_eA9gW9mkCTr2JzMz4nqdhY%2BtaGshStrVxLO3QOQ7MoUhWFg@mail.gmail.com> References: <5A0F14CD.3040407@omnilan.de> <CA%2B_eA9giPsMJ2_O1CLvOro=rMm5TaJyQ-et_U01Re5J9%2B9VSqg@mail.gmail.com> <5A149107.9060507@omnilan.de> <CA%2B_eA9gW9mkCTr2JzMz4nqdhY%2BtaGshStrVxLO3QOQ7MoUhWFg@mail.gmail.com>
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Bezüglich Vincenzo Maffione's Nachricht vom 22.11.2017 09:04 (localtime): > > > 2017-11-21 21:48 GMT+01:00 Harry Schmalzbauer <freebsd@omnilan.de > <mailto:freebsd@omnilan.de>>: > > Bezüglich Vincenzo Maffione's Nachricht vom 21.11.2017 09:39 > (localtime): > … > > > > If this is the case, although you are allowed to do that, I don't think > > it's a convenient way to use netmap. > > Since VLAN interfaces like vlan0 do not have (and cannot have) native > > netmap support, you are falling back to emulated netmap adapters (which > > are probably buggy on FreeBSD, specially when combined with VALE). > > Apart from bugs I think that with this setup you can't get decent > > performance that would justify using netmap rather than the standard > > kernel bridge and TAP devices. > > Hello, > > lockup happened earlier than expected. > This time 'vale-ctl' still reported (-l) the configuration. > One guest, using if_vtnet(4)-virtio-net#vale2:korso, showed: > dmz: watchdog timeout on queue 0 > (dmz is the renamed if_vtnet(4)) > > I could attach tcpdump to the uplink interface and also to all vlan > children. > Complete silence everywhere. So it seems the nic stopped processing > anything. > > Do you think that symptom could be caused by my special vale > integration, so that bugs in netmap emulation could crash the NIC? > Or is it unlikely that this is related. > > I hadn't prepared a debug kernel for the host, so the machine rebooted > without again. > I think I'll have to start with replacing vale first, to narrow down > possible causes. Today I was lucky, the lockup happend after business > hours, but I won't rely on that. > At least I know if I really need to look for a debug netmap kernel, or > possibly there's something else... > > Thanks, > > -harry > > > > I can't really say anything without a stack trace or meaningful logs. > There is a thing that you may do to see if the bug comes out of a bad > interaction between > emulated netmap and VALE. > Instead of attaching the vlan interfaces to VALE you can connect VALE to > the vlan interface > through the "bridge" program. In this way nothing changes from the > functional point of view, > but you are not attaching anymore the VLAN interface to VALE (and you > are using an additional process). > > So instead of > > # vale-ctl vale0:vlan0 > > you would have > > # bridge netmap:vlan0 vale0:vv # "vv" can be anything Hello Vincenzo, thank you very much for that interesting hint. I prepared a netgraph setup yesterday evening, but I'll try your suggestion first. Unfortunately I don't have time to prepare a debug kernel until next reboot (today evening), but maybe the result of this config is interesting/meaningful using the same kernel. Will keep you informed, thanks, -harry
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