Date: Wed, 22 Nov 2017 10:18:58 +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: <5A154102.10007@omnilan.de> In-Reply-To: <5A1537B3.9030603@omnilan.de> 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> <5A1537B3.9030603@omnilan.de>
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Bezüglich Harry Schmalzbauer's Nachricht vom 22.11.2017 09:39 (localtime): > 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 Since this doesn't need a reboot and I'm in adventure mood, I just tried it at runtime. Unfortunately I can't find bridge documentation besides the source code. It doesn't detach from terminal here: bridge built Oct 8 2017 12:59:57 060.359974 main [244] ------- zerocopy NOT supported 060.359987 main [251] Wait 4 secs for link to come up... 064.365872 main [255] Ready to go, nic1_egn 0x0/1 <-> vale4:nic1egn 0x0/1. 068.084364 main [306] poll timeout [0] ev 1 0 rx 0@33 tx 1022, [1] ev 1 0 rx 0@34 tx 1023 072.565559 main [306] poll timeout [0] ev 1 0 rx 0@34 tx 1022, [1] ev 1 0 rx 0@35 tx 1023 … In general, things are working. Is bridge staing in the foreground by design? Thanks, -harry
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