Re: [Qemu-devel] Monitoring Screen Activity in QEMU/KVM

[Claudio Fontana <claudio.fontana@gmail.com>]

> Claudio Fontana <address@hidden> writes:
> > Shehbaz Jaffer wrote:
> >
> >> I want to determine the amount of screen activity taking place on VGA
> >> monitor/ Screen for different applications (eg. playing vlc video, normal
> >> typing.)
> >>
> >> When I do not start the X server, I can easily determine the screen activity
> >> by counting the number of pages accessed in the region 0xA0000 - 0xBffff
> >> (This is the VGA Monitor region in boot screen).
> >>
> >> However when I start the X Server, A diffrent set of pages are hit. Could
> >> anyone please explain how the VGA Monitor works in QEMU? Or if someone could
> >> suggest an alternate solution to determine amount of screen activity while
> >> playing diffrent applications?
> >>
> >> [NOTE : I have already checked for the region where X server pages are
> >> mapped using cat /proc/iomem. But pages are not getting written to the
> >> "possible" X server mmapped region.]
> >>
> >> Regards,
> >
> > If you define "screen activity" = "number of pages accessed in the
> > range 0xa0000-0xbffff per unit of time", you could keep your thing
> > going by just using the generic "vga" driver in your Xorg
> > configuration, and that would keep your model valid I think.
>
> Pretty sure the vga driver will use VESA interfaces and the VESA BIOS
> will use PCI bar mapping.

you are thinking of the generic 'vesa' driver:
http://cgit.freedesktop.org/xorg/driver/xf86-video-vesa/

There is also a generic 'vga' driver:
http://cgit.freedesktop.org/xorg/driver/xf86-video-vga/

That said, I was being semi-serious: an Xorg running on plain vga
driver is hardly a realistic use-case.

> You could also trap accesses to where the BAR gets mapped on the PCI
> device.  Far better to just register a DisplayChangeListener though and
> let QEMU do the heavy lifting.
>
> Or use VNC as Richard mentioned elsewhere.
>
> Regards,
>
> Anthony Liguori
>
> >
> > Claudio