Date: Tue, 21 Nov 2017 14:46:38 +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: <5A142E3E.5010002@omnilan.de> In-Reply-To: <CA%2B_eA9g85z0jkgR7of__x18K9muG4YouOgXKa5ySw16D=YE19g@mail.gmail.com> References: <5A0F14CD.3040407@omnilan.de> <CA%2B_eA9giPsMJ2_O1CLvOro=rMm5TaJyQ-et_U01Re5J9%2B9VSqg@mail.gmail.com> <5A13F8A8.2020209@omnilan.de> <CA%2B_eA9g85z0jkgR7of__x18K9muG4YouOgXKa5ySw16D=YE19g@mail.gmail.com>
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Bezüglich Vincenzo Maffione's Nachricht vom 21.11.2017 14:26 (localtime): > It may be that your is not a deadlock but some kind of crash. Enabling > debugging features would probably help (e.g. to get a stack trace). > Maybe your lockup/crash happened because you did some reconfiguration > (ring size, number of rings, etc.) while netmap was active and doing so > you triggered > some hidden bug. The host was completely untouched when these lockups occured in late test phase. Only guests were configured/utilized. No previous (short term stress) test had caused any problem in that path. It first showed up with real-world (unstressed) tests. The last-minute change I described was with powered down guests and the host was rebooted (ppt dev changed in loader.conf). The host isn't going to be reconfigured in any way. Let's wait and see if the lockup shows up again (after not limiting NICs rx/tx descriptors and increasing netmap ring size). Considering your suspect that emulated netmap code in FreeBSD might be buggy, and the fact that I'm not able to debug it myself, I guess switching from vale to netgraph is my best bet. It's not much effort and causes almost no downtime. But it would disallow future ptnetmap extension... I'd prefere to stay with vale, although I'm using emulated mode only... So at first occurance, I'll install the debug kernel and see if that makes any difference. Thanks, -harry
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