Date: Thu, 11 Aug 2016 14:29:10 +0200 From: "Hoyer-Reuther, Christian" <Christian.Hoyer-Reuther@cac-chem.de> To: =?iso-8859-1?Q?Roger_Pau_Monn=E9?= <roger.pau@citrix.com>, Wei Liu <wei.liu2@citrix.com> Cc: "freebsd-xen@freebsd.org" <freebsd-xen@freebsd.org> Subject: Re: 'Live' Migrate messes up NTP on FreeBSD domU - any suggestions? Message-ID: <41E487BC91654544B2B8F31096F2D9D4D1516495CA@ex1> In-Reply-To: <20160729082905.46js7o3zp6iwuibd@mac> References: <41E487BC91654544B2B8F31096F2D9D4D1514D1D8E@ex1> <20160714103016.4hgfzsjgkkgtkkgg@mac> <41E487BC91654544B2B8F31096F2D9D4D1514D1E88@ex1> <20160720093111.mpmp27wol7j3ge3d@mac> <41E487BC91654544B2B8F31096F2D9D4D1516490E9@ex1> <20160722115542.dopzb63dgkilqall@mac> <FA258C50EA60D4DE44D9289C@[10.12.30.106]> <20160725144314.yhggviqhsqzgux2w@mac> <20160725153714.GW27082@citrix.com> <20160729082905.46js7o3zp6iwuibd@mac>
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Hello,
sorry for the late response, but now I'm back from vacation and did some ne=
w tests.
I installed a new VM using the FreeBSD-11.0-ALPHA6-amd64-20160701-r302303-d=
isc1.iso, then updated to HEAD r303908 and installed xe-guest-utilities-6.2=
.0_2 from HEAD ports r420055. Xenguest_enable=3D"YES" is set in /etc/rc.con=
f.
I tested VM migration from XenCenter (XenMotion).
There are no more time issues after migration.
I did 4 migrations and at 2 migrations I noticed the following problems:
When the migration finishes then the VM console switches to the VGA BIOS sc=
reen (Plex86/Bochs VGABios ...), the VM console freezes, the VM is not reac=
hable over network and in XenCenter I see the first 2 CPU's raising up to 1=
00 percent. Screenshots attached.
Then after 10 minutes the CPU usage goes down, the VM console is responsive=
again and the machine is reachable over network.
Regards,
Christian
> -----Original Message-----
> From: Roger Pau Monn=E9 [mailto:roger.pau@citrix.com]
> Sent: Friday, July 29, 2016 10:29 AM
> To: Wei Liu
> Cc: Karl Pielorz; Hoyer-Reuther, Christian; freebsd-xen@freebsd.org
> Subject: Re: 'Live' Migrate messes up NTP on FreeBSD domU - any suggestio=
ns?
>=20
> On Mon, Jul 25, 2016 at 04:37:14PM +0100, Wei Liu wrote:
> > On Mon, Jul 25, 2016 at 04:43:43PM +0200, Roger Pau Monn=E9 wrote:
> > > Adding Wei to the Cc list since he added the multiqueue functionality=
.
> > >
> > > On Mon, Jul 25, 2016 at 02:59:02PM +0100, Karl Pielorz wrote:
> > > >
> > > > --On 22 July 2016 13:55 +0200 Roger Pau Monn=E9 <roger.pau@citrix.c=
om>
> wrote:
> > > >
> > > > > In my environment I've migrated a FreeBSD VM with 2 cpus for > 10=
0
> > > > > consecutive times without seeing any issues (or freezes), althoug=
h
> this
> > > > > was with OSS Xen and without xe-guest-utilities. Karl, have you
> tested
> > > > > HEAD recently?
> > > >
> > > > Ok, I have tested this with r303286 - it seems to work OK. The host=
s
> gain no
> > > > time that I can see while migrating, and NTP stays happy.
> > > >
> > > > I did get a panic after about 40 migrations - but that seems to be
> some
> > > > network issue or something...
> > > >
> > > > ('panic called with 0 available queues / dbt_trace_self_wrapper /
> vpanic /
> > > > kassert_panic / xn_txq_mq_start / ether_output / udp_send /
> sosend_dgram /
> > > > kern_sendit / sendit / sys_sendto / amd64_syscall / Xfast_syscall)
> > >
> > > I haven't been able to reproduce this, but I think it's possible that=
if
> you
> > > migrate an active netfront xn_txq_mq_start might be called during the
> > > migration, just in the middle of the setup_device reconfiguation (whi=
le
> > > info->num_queues is 0).
> > >
> > > Wei, I think netif_disconnect_backend should set IFF_DRV_OACTIVE in
> order to
> > > notify the net subsystem that the queues are full, so no further call=
s
> to
> > > xn_txq_mq_start happen until the resume has finished, do you agree?
> > >
> >
> > Perhaps clear IFF_DRV_RUNNING and only set it when the device is ready?
> > Looking at the manpage is seems more appropriate to me semantically.
>=20
> Hello Karl and Christian, I have the following patches that solve all the
> issues I've seen with live migration, with those I've been able to migrat=
e a
> VM > 100 times without seeing any issues. Could you give them a try?
>=20
> BTW, I haven't been able to reproduce Karl's crash ("called with 0 availa=
ble
> queues"), but I've added a condition that should prevent it from triggeri=
ng
> anyway. Patches are here:
>=20
> https://reviews.freebsd.org/D7349
> https://reviews.freebsd.org/D7362
> https://reviews.freebsd.org/D7363
>=20
> It doesn't really matter in which order you apply them as long as both 3 =
are
> applied. Ideally I would like to commit them on Monday, so that I can MFC
> them to stable/11 before the releng/11 branch, could you please provide s=
ome
> feedback before then?
>=20
> Thanks, Roger.
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