I don't think these issue have much to do with Spice, but with the amount of memory oVirt sets to VMs by default, which in some cases for desktop usage seems too little. A field where that could be adjusted without having to edit files in the Engine would probably resolve this issue, or am I missing anything ?


On 07/03/2018 15:43, Michal Skrivanek wrote:

On 7 Mar 2018, at 14:03, FERNANDO FREDIANI <fernando.fredi...@upx.com <mailto:fernando.fredi...@upx.com>> wrote:

Hello Gianluca

Resurrecting this topic. I made the changes as per your instructions below on the Engine configuration but it had no effect on the VM graphics memory. Is it necessary to restart the Engine after adding the 20-overload.properties file ? Also I don't think is necessary to do any changes on the hosts right ?

correct on both

On the recent updates has anything changed in the terms on how to change the video memory assigned to any given VM. I guess it is something that has been forgotten overtime, specially if you are running a VDI-like environment whcih depends very much on the video memory.

there were no changes recently, these are the most recent guidelines we got from SPICE people. They might be out of date. Would be good to raise that specifically (the performance difference for default sizes) to them, can you narrow it down and post to spice-de...@lists.freedesktop.org <mailto:spice-de...@lists.freedesktop.org>?


Let me know.

Fernando Frediani

On 24/11/2017 20:45, Gianluca Cecchi wrote:
On Fri, Nov 24, 2017 at 5:50 PM, FERNANDO FREDIANI <fernando.fredi...@upx.com <mailto:fernando.fredi...@upx.com>> wrote:

    I have made a Export of the same VM created in oVirt to a server
    running pure qemu/KVM and which creates new VMs profiles with
    vram 65536 and it turned on the Windows 10 which run perfectly
    with that configuration.

    Was reading some documentation that it may be possible to change
    the file /usr/share/ovirt-engine/conf/osinfo-defaults.properties
    in order to change it for the profile you want but I am not sure
    how these changed should be made if directly in that file, on
    another one just with custom configs and also how to apply them
    immediatelly to any new or existing VM ? I am pretty confident
    once vram is increased that should resolve the issue with not
    only Windows 10 VMs, but other as well.

    Anyone can give a hint about the correct procedure to apply this
    change ?

    Thanks in advance.

Hi Fernando,
based on this:
https://www.ovirt.org/develop/release-management/features/virt/os-info/ <https://www.ovirt.org/develop/release-management/features/virt/os-info/>

you should create a file of kind
but I think you can only overwrite the multiplier and not directly the vgamem (or vgamem_mb in rhel 7) values

so that you could put something like this inside it:

os.windows_10.devices.display.vramMultiplier.value = 2
os.windows_10x64.devices.display.vramMultiplier.value = 2

I think there are no values for vgamem_mb

I found these two threads in 2016
that confirms you cannot set vgamem
that suggests to create a hook

Just a hack that came into mind:
in a CentOS vm of mine in a 4.1.5 environment I see that by default I get this qemu command line

-device qxl-vga,id=video0,ram_size=67108864,vram_size=33554432,vram64_size_mb=0,vgamem_mb=16,bus=pci.0,addr=0x2

Based on this:
https://www.ovirt.org/documentation/draft/video-ram/ <https://www.ovirt.org/documentation/draft/video-ram/>

you have
vgamem = 16 MB * number_of_heads

I verified that if I edit the vm in the gui and set Monitors=4 in console section (but with the aim of using only the first head) and then I power off and power on the VM, I get now

-device qxl-vga,id=video0,ram_size=268435456,vram_size=134217728,vram64_size_mb=0,vgamem_mb=64,bus=pci.0,addr=0x2

I have not a client to connect and verify any improvement: I don't know if you will be able to use all the new ram in the only first head with a better experience or if it is partitioned in some way...
Could you try eventually?


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