Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio nic

O

obrienmd

Member
Oct 14, 2009
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After install (install process did not have the problem), guest system is barely responsive w/ "events/1" using lots of cpu in top. Removing virtio nic from the config and stopping/starting vm makes everything snappy. e1000 also makes everything snappy.

Guest: Fresh Ubuntu 10.04.2 install

Config:
name: hostname.praece.com
bootdisk: virtio0
ostype: l26
memory: 4096
sockets: 4
boot: dc
freeze: 0
cpuunits: 1000
acpi: 1
kvm: 1
virtio0: array:vm-107-disk-1,cache=none
vlan0: virtio=4E:0A:D3:DE:E4:D2

Pveversion Output:
pve-manager: 1.7-12 (pve-manager/1.7/5490)
running kernel: 2.6.35-1-pve
proxmox-ve-2.6.35: 1.7-10
pve-kernel-2.6.32-3-pve: 2.6.32-18
pve-kernel-2.6.32-4-pve: 2.6.32-31
pve-kernel-2.6.32-2-pve: 2.6.32-8
pve-kernel-2.6.35-1-pve: 2.6.35-10
pve-kernel-2.6.24-9-pve: 2.6.24-18
pve-kernel-2.6.24-8-pve: 2.6.24-16
qemu-server: 1.1-29
pve-firmware: 1.0-10
libpve-storage-perl: 1.0-16
vncterm: 0.9-2
vzctl: 3.0.24-1pve4
vzdump: 1.2-11
vzprocps: 2.0.11-1dso2
vzquota: 3.0.11-1
pve-qemu-kvm: 0.14.0-2
ksm-control-daemon: 1.0-5
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

can you report benchmarks between the two configs? running "snappy" is not that informative and others cannot test the same.

and give info about your host!
 
Last edited:
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

Yeah, sorry, failed at that description. When I say inoperable, I mean I can barely use the VM. The console constantly misses keystrokes via vnc, the VM takes 10 minutes to boot, etc, etc. I haven't tested network bandwidth as I would have to sit in front of the vnc window for an hour to login, apt-get iperf, test. It's not the network that's slow, its the virtio NIC that is killing the machine's general performance via this "events/1" process.
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

ok, I think I can reproduce it, but I see it only on 2.6.35. can you test with the latest 2.6.32 (from pvetest)?
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

Tom - our testing infrastructure is pretty maxed right now, probably would not be able to do that for a few days on 2.6.32
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

ubuntu 1010 seems not have this issue, also Squeeze is working.
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

tom said:
ok, I think I can reproduce it, but I see it only on 2.6.35. can you test with the latest 2.6.32 (from pvetest)?
Click to expand...

I'm having the same issue with ubuntu 10.04 guests after upgrading to 1.8.
2.6.35 - very slow guests and high events/0 cpu usage
2.6.32 - works ok

P.S. It seems to help if I unload vhost_net module before starting guests on proxmox host with 2.6.35, so it may be related to vhost feature (I think thats only available under 2.6.35 kernel so it makes sense that it works under 2.6.32).
 
Last edited:
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

l.mierzwa said:
I'm having the same issue with ubuntu 10.04 guests after upgrading to 1.8.
2.6.35 - very slow guests and high events/0 cpu usage
2.6.32 - works ok

P.S. It seems to help if I unload vhost_net module before starting guests on proxmox host with 2.6.35, so it may be related to vhost feature (I think thats only available under 2.6.35 kernel so it makes sense that it works under 2.6.32).
Click to expand...

Under 2.6.35 kernel from 1.7 (upgraded to 1.8 but not rebooted to new kernel) I have the same issues so it's triggered by new kvm, not by kernel.
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

dietmar said:
Why do you think so?
Click to expand...

I can't find any bug reports regarding this issue elsewhere so it's possible that this is triggered by some patches added in proxmox. I come across the post I've linked and it's related to vhost_net and qemu-kvm-0.14 included in proxmox 1.8. It's blind guess but it touches things that are problematic.
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

Hi,

I see the same problem with an Ubuntu 10.0.4.2 VM. It's a KVM VM and I use 2.6.35 kernel. I was using it in 1.7 and upgraded with this kernel to 1.8. But it seems to not be always slow. At this moment, it runs normally. Some times before, it was so slow (~10 seconds to type one character) that it was unusable.

Here is the VM configuration :
name: cvs-stm
ide2: cdrom,media=cdrom
sockets: 1
vlan0: virtio=4E:FC:3A:F2:8B:98
bootdisk: virtio0
ostype: l26
memory: 512
onboot: 1
boot: cad
freeze: 0
cpuunits: 1000
acpi: 1
kvm: 1
vga: cirrus
cores: 2
virtio0: local:102/vm-102-disk-1.raw
Click to expand...
and pveversion :
# pveversion -v
pve-manager: 1.8-15 (pve-manager/1.8/5754)
running kernel: 2.6.35-1-pve
proxmox-ve-2.6.35: 1.8-10
pve-kernel-2.6.35-1-pve: 2.6.35-10
pve-kernel-2.6.18-2-pve: 2.6.18-5
qemu-server: 1.1-30
pve-firmware: 1.0-11
libpve-storage-perl: 1.0-16
vncterm: 0.9-2
vzctl: 3.0.24-1pve4
vzdump: 1.2-11
vzprocps: 2.0.11-1dso2
vzquota: 3.0.11-1
pve-qemu-kvm: 0.14.0-2
ksm-control-daemon: 1.0-5
Click to expand...
This machine is rather old and was using a qcow2 image file. I now use only raw. As it was the only VM using qcow2 (and I seem to recall there was a discrepancy between the image file type as described in /etc/qemu-server, and in the web interface), I converted qcow2 to raw, but with no effect.
I did not try to use an e1000 network interface, for example, instead of virtio...

Note : inside the VM the kernel is :
$ uname -a
Linux cvs-stm 2.6.32-30-generic-pae #59-Ubuntu SMP Tue Mar 1 23:01:33 UTC 2011 i686 GNU/Linux
Click to expand...
 
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Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

I'm seeing this every 2-3 days with an instance running Ubuntu 10.04.2 LTS (2.6.32-32-generic-pae #62-Ubuntu SMP Wed Apr 20 22:10:33 UTC 2011 i686 GNU/Linux). Suddenly, events/0 starts hogging the CPU, everything slows down to a crawl. Only way out is to reboot.

I've read about various fixes (like, disabling acpi) but nothing helped so far.

vm:~# pveversion -v
pve-manager: 1.8-17 (pve-manager/1.8/5948)
running kernel: 2.6.35-1-pve
proxmox-ve-2.6.35: 1.8-11
pve-kernel-2.6.35-1-pve: 2.6.35-11
pve-kernel-2.6.24-7-pve: 2.6.24-11
pve-kernel-2.6.24-9-pve: 2.6.24-18
pve-kernel-2.6.24-5-pve: 2.6.24-6
pve-kernel-2.6.24-2-pve: 2.6.24-5
qemu-server: 1.1-30
pve-firmware: 1.0-11
libpve-storage-perl: 1.0-17
vncterm: 0.9-2
vzctl: 3.0.26-1pve4
vzdump: 1.2-12
vzprocps: 2.0.11-2
vzquota: 3.0.11-1
pve-qemu-kvm: 0.14.0-3
ksm-control-daemon: 1.0-5
Click to expand...

dmesg on the client here: https://gist.github.com/1010336

Any idea about what to do? Kind regards,

Christian
 
Last edited:
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

try kvm 0.14.1 from pvetest, any difference?
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

tom said:
try kvm 0.14.1 from pvetest, any difference?
Click to expand...

No difference.

The problem is "fixable" by installing a newer kernel in the Ubuntu guest, i.e. from http://kernel.ubuntu.com/~kernel-ppa/mainline/

Other thing is how to install this kernel, if the guest doesn't even boot because of this issue (live cd helps then)...

Ubuntu 10.10 does not show this phenomenon.
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

How we solved it, is to install linux-image-2.6.25-25-virtual on ubuntu 10.04
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

Hi
it seems we hit the very same bug here with one ubuntu VM.

Any solution without telling the user to get a new kernel or at least without breaking ubuntu LTS ont eh VM?

regards
hk
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

I hit the problem recently, with several machines running Ubuntu 10.04.2, and using virtio NIC, after a new kernel update. As was said by a previous post, converting to another NIC type, in my case, e1000, solved the problem.

Alain
 
Re: Ubuntu 10.04.2 KVM fresh install, inoperable w/ high events/1 usage due to virtio

Alain,
thank you for your quick input - I removed virtio ethernet and added e1000.
VM shutdown and reboot worked flawless, luckily ubuntu also took the e1000 as its eth0 and all worked fine.

kindest regards
hk
 
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