On 13 Oct 2017, at 0:11, Mike Larkin wrote:
On Thu, Oct 12, 2017 at 10:36:42PM +0200, Michał Koc wrote:
On Thu, Oct 12, 2017 at 01:23:36PM +0200, Michał Koc wrote:
On Sun, Oct 08, 2017 at 11:59:52PM +0200, Oliver Marugg wrote:
On 7 Oct 2017, at 22:01, Mike Larkin wrote:
On Sat, Oct 07, 2017 at 02:19:58PM +0200, Oliver Marugg wrote:
Just to add a 4th situation of hangs: Login via proxmox
(pve)/kvm
serial
console (via noVNC), login successful: Vm guest in pve hangs,
cpu
usage at
above 102%. Only way is to hard stop the Vm guest. -oliver
sounds like a kvm bug. Ask your provider to investigate the host
side
when this
happens.
Thanks Mike, will do so. The proxmox guys have also the idea that
it could
be a bug in kvm hypervisor (which is the hypervisor part for
proxmox) and
will affect OpenBSD since 4.9, they wrote me in their public
forum. As far
as I understood they do not know what OpenBSD needs in kvm or
what/where
should be fixed in kvm run OpenBSD without that freezes.
-oliver
From what I read, the cpu spins to 100%, which means somewhere on
the host it's
likely spinning also. Start with systrace/ptrace/ktrace/whatever
on the host
qemu-kvm and go from there...
-ml
Hi,
it looks like the cpu process of kvm (CPU 0/KVM) is issuing 1500+
of
ioctl(15, KVM_RUN, 0) per second while running OpenBSD 6.2 guest.
What CPU profile is being presented to the OpenBSD guest?
I've seen things like this happen when a vCPU is claimed to have
monitor/mwait
support, but the hypervisor implements those as NOPs, which just
results in
spinning like this.
In short - try changing the type of CPU presented to the guest and
see if that
changes behaviour. At least then you'll have more data points to
work with.
-ml
Okey,
How would You disable monitor/mwait support in KVM to be presented to
guest
?
Well, monitor/mwait was just what I recall contributing to something
*like*
this.
If you can determine the guest %rip during each ioctl(vm_run) and give
me a
kernel or disassembly I may be able to see if it's something obvious.
That, or describe a way I can repro this locally. I have a machine I
could
put linux on for an evening to test.
-ml
proxmox is debian 9 based they uses an ubuntu kernel 4.10.17-3-pve
(modified?). It seems that makes it a step harder to compare in this
case.
I tested my OpenBSD Guestswith different processor types like Mike
suggested, stablest fit shows as kvm64 (eq. pentium4 I think) which is
also standard in proxmox kvm. Other processors types like core2duo,
pentium or opteron freeze/hangs somewhen within 30 minutes after
starting, I tested all through.
changing CPU to pentium or setting <feature policy='disable'
name='monitor'/> does not actually change anything in scope of host
cpu
utilization....
BR
M.K.
In case of linux guest the process issues about 15 of those ioctls
per
second.
In any case I cannot make openbsd to starve KVM host cpu. OpenBSD
uses at
most(when idle) 7% of cpu.
My versions:
- OpenBSD 6.2 amd64
- KVM 2.8.1
BR
M.K.
