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

[Adam Goryachev <mailinglists@xxxxxxxxxxxxxxxxxxxxxx>]

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  libxen-4.1 4.1.4-3+deb7u1               amd64        Public libs for Xen
ii  libxenstore3.0 4.1.4-3+deb7u1               amd64        Xenstore 
communications library for Xen
ii  xen-hypervisor-4.1-amd64 4.1.4-3+deb7u1               amd64        
Xen Hypervisor on AMD64
ii  xen-linux-system-3.2.0-4-amd64 3.2.60-1+deb7u1              
amd64        Xen system with Linux 3.2 on 64-bit PCs (meta-package)
ii  xen-linux-system-amd64 3.2+46                       amd64        Xen 
system with Linux for 64-bit PCs (meta-package)
ii  xen-system-amd64 4.1.4-3+deb7u1               amd64        Xen 
System on AMD64 (meta-package)
ii  xen-utils-4.1 4.1.4-3+deb7u1               amd64        XEN 
administrative tools
ii  xen-utils-common 4.1.4-3+deb7u1               all          Xen 
administrative tools - common files
ii  xenstore-utils 4.1.4-3+deb7u1               amd64        Xenstore 
utilities for Xen
An example config file:
kernel        = "/usr/lib/xen-4.1/boot/hvmloader"
builder        = 'hvm'
memory        = 8192
device_model    = '/usr/lib/xen-4.1/bin/qemu-dm'
localtime    = 1
name        = "hostname"
cpus        = "2,3,4,5"
vcpus        = 4
viridian    = 1
disk = [ 'phy:/dev/mapper/mpathpt19,hda,w' ]
vif        = ['bridge=xenbr0, mac=00:16:3e:06:65:19']
sdl        = 0
vnc        = 1
vncviewer    = 0
vncconsole    = 0
vncdisplay    = 19
vncunused    = 0
stdvga        = 0
usb        = 1
usbdevice    = 'tablet'
acpi        = 1
apic        = 1
on_reboot    = 'restart'
on_poweroff    = 'destroy'
on_crash    = 'restart'
audio        = 1
soundhw        = 'sb16'

Regards,
Adam

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

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