Xen project Mailing List

On Wed, Jul 30, 2014 at 12:06 PM, Adam Goryachev <mailinglists@xxxxxxxxxxxxxxxxxxxxxx> wrote:

On 30/07/14 09:34, Christian Fassina Costa wrote:

Hey guys,

It seems like the qemu-dm processes on the dom0 use quite a lot of CPU when usbdevice=tablet is used for a Windows a guest.

Setting that to 'none' fixes the problem, however, the mouse pointer doesn't track correctly when connecting to VNC. This is what I found out from looking at other reports of this problem.

A hypervisor running Xen 4.0.1 with a 2.6.32-5-xen-amd64 doesn't seem to exhibit the same high CPU usage.

I've also tried it on different set ups:

- Xen 4.1.5 and 3.2.0-61-generic
- Xen 4.1.6.1 and 3.2.0-51-generic

Just wondering if anyone would have a solution for this issue. I did some research and it looks like quite a few people have come across this problem.

I'm also not sure if this is the right place to be asking that, however, since I couldn't find any bug reports so I'm wondering if perhaps there is a solution to the high CPU usage or the mouse tracking over VNC.

Any help or pointers as to how this could be solved would be appreciated.

I'm not sure if this is of any assistance, but I don't see the issue with high cpu usage on VM's with usbdevice=tablet. However, I *DO* see the issue with the mouse in VNC, but not on first boot, only after a live migration. So, on bootup, the mouse works perfectly over VNC. After I live migrate to another dom0, then the mouse does not work properly.

How do you determine "high CPU usage"? Is that 5% or 75% or 100%? one core/CPU or all available?

If anyone can suggest a solution to the mouse working after live migrate that would be appreciated.

I'm using debian stable packages:
ii Âlibxen-4.1 4.1.4-3+deb7u1 Â Â Â Â Â Â Â amd64 Â Â Â ÂPublic libs for Xen
ii Âlibxenstore3.0 4.1.4-3+deb7u1 Â Â Â Â Â Â Â amd64 Â Â Â ÂXenstore communications library for Xen
ii Âxen-hypervisor-4.1-amd64 4.1.4-3+deb7u1 Â Â Â Â Â Â Â amd64 Â Â Â ÂXen Hypervisor on AMD64
ii Âxen-linux-system-3.2.0-4-amd64 3.2.60-1+deb7u1 Â Â Â Â Â Â Âamd64 Â Â Â ÂXen system with Linux 3.2 on 64-bit PCs (meta-package)
ii Âxen-linux-system-amd64 3.2+46 Â Â Â Â Â Â Â Â Â Â Â amd64 Â Â Â ÂXen system with Linux for 64-bit PCs (meta-package)
ii Âxen-system-amd64 4.1.4-3+deb7u1 Â Â Â Â Â Â Â amd64 Â Â Â ÂXen System on AMD64 (meta-package)
ii Âxen-utils-4.1 4.1.4-3+deb7u1 Â Â Â Â Â Â Â amd64 Â Â Â ÂXEN administrative tools
ii Âxen-utils-common 4.1.4-3+deb7u1 Â Â Â Â Â Â Â all Â Â Â Â ÂXen administrative tools - common files
ii Âxenstore-utils 4.1.4-3+deb7u1 Â Â Â Â Â Â Â amd64 Â Â Â ÂXenstore utilities for Xen

An example config file:
kernel Â Â Â Â= "/usr/lib/xen-4.1/boot/hvmloader"
builder Â Â Â Â= 'hvm'
memory Â Â Â Â= 8192
device_model Â Â= '/usr/lib/xen-4.1/bin/qemu-dm'
localtime Â Â= 1
name Â Â Â Â= "hostname"
cpus Â Â Â Â= "2,3,4,5"
vcpus Â Â Â Â= 4
viridian Â Â= 1
disk = [ 'phy:/dev/mapper/mpathpt19,hda,w' ]
vif Â Â Â Â= ['bridge=xenbr0, mac=00:16:3e:06:65:19']
sdl Â Â Â Â= 0
vnc Â Â Â Â= 1
vncviewer Â Â= 0
vncconsole Â Â= 0
vncdisplay Â Â= 19
vncunused Â Â= 0
stdvga Â Â Â Â= 0
usb Â Â Â Â= 1
usbdevice Â Â= 'tablet'
acpi Â Â Â Â= 1
apic Â Â Â Â= 1
on_reboot Â Â= 'restart'
on_poweroff Â Â= 'destroy'
on_crash Â Â= 'restart'
audio Â Â Â Â= 1
soundhw Â Â Â Â= 'sb16'

Regards,
Adam

--
Adam Goryachev Website Managers www.websitemanagers.com.au

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Re: [Xen-users] qemu-dm dom0 high CPU usage when usbdevice=tablet