What VM performance should I expect with my PC?

beta990 · 2016-03-05 21:44:31

The last few days I'm trying to run Windows 10 in a VM with libvirt, and so far the performance is mixed.

PC specs.:
- Intel i5-2400 @ 2.4Ghz
- Samsung 850 SSD (root) (btrfs) / Samsung 1TB HD103SJ (as image store) (btrfs)
- Kingston ValueRAM 8GB DDR3 1333Mhz
- ASUS P8H67M Pro (B3)
- Club 3D Radeon R9 270 royalQueen

This is my XML config of the Windows 10 machine: http://pastebin.com/YA8DdpsB
At the moment I've installed all drivers (no missing drivers in the device manager), running the latest guest tools (SPICE, Virtio), etc.

I know my system isn't the best when running VM's: loading raw images from a HDD instead of SSD, low memory, etc.
What performance should I expect? Is it normal to have 'freezes' on starting and when using the VM?

My 'target' is to able to run (mostly tear-free) Adobe apps, since it doesn't run in Wine (without any issues), but with the performance I have atm. it isn't even possible to render a simple PSD/AI inside the VM.
When Google-ling and reading multiple topics about libvirt, etc. I'm still confuse; KVM should 'talk'/work (better) with the host hardware, reducing the number of layers and even could to lead to gaming inside a VM.
Do you really need an Intel i7 skylake, 32GB of RAM, Nvme, etc. to get a decent amount of performance? Not saying I don't want to upgrade (in the future), I just would like the know the right perspective.

Many thanks!

Last edited by beta990 (2016-03-05 21:44:48)

Trilby · 2016-03-05 22:06:39

I run windows VMs with *much* lower spec harware than that. It's not always snappy, but neither is that OS on bare metal (in fact I oddly get subjectively better performance with win7 in a VM than on bare metal on the exact same machine).

That said, I have no experience with btrfs, and I can imagine ways - depending on your btrfs settings - that the host filesystem might cause issues in this case. The VM "harddisk" is one large file from the hosts perspective, and depending on your btrfs settings, there may be a lot of work to be done every time that "file" changes. There are btrfs settings to mitigate such concerns - you may already be using them - but that is definitely something to look into.

beta990 · 2016-03-05 22:30:13

Trilby wrote:

I run windows VMs with *much* lower spec harware than that. It's not always snappy, but neither is that OS on bare metal (in fact I oddly get subjectively better performance with win7 in a VM than on bare metal on the exact same machine).
That said, I have no experience with btrfs, and I can imagine ways - depending on your btrfs settings - that the host filesystem might cause issues in this case. The VM "harddisk" is one large file from the hosts perspective, and depending on your btrfs settings, there may be a lot of work to be done every time that "file" changes. There are btrfs settings to mitigate such concerns - you may already be using them - but that is definitely something to look into.

Thanks for the btrfs tip! Forgot to tweak the mount options, will double check.
The HDD isn't the fastest, I'm going to try with a different HDD/SSD, without encryption and EXT4 as filesystem, maybe that will increase performance a bit.

Could you tell me a bit more about your performance, and if you have any 'freezes', etc.?
Do you work with libvrt? Or use QEMU directly?

Overall the GPU performance seems to be pretty low/buggy, what is the overall video/graphical recommendation? QXL + Spice?
I also see user reports about using vmware with VNC instead of Spice?

The information I find is really conflicting and a bit confusing, it seems libvrt/QEMU/KVM, etc. is still a work in process?

Trilby · 2016-03-05 22:46:25

I don't know much about virtualization - very very little really. But I just wanted to share that your hardware *should* be ample for "normal" use of windows VMs. I don't use libvirt. I use pretty vanilla qemu settings with kvm. I don't get any freezes, and like I said, performance is at least as good as on bare metal.

But also my host system is pretty minimal so nothing is competing for resources. I also don't do any graphics intensive stuff on the VM. Mainly just test websites and simple programs to make sure they actually run properly on windows.

beta990 · 2016-03-08 18:19:31

Trilby wrote:

I don't know much about virtualization - very very little really. But I just wanted to share that your hardware *should* be ample for "normal" use of windows VMs. I don't use libvirt. I use pretty vanilla qemu settings with kvm. I don't get any freezes, and like I said, performance is at least as good as on bare metal.
But also my host system is pretty minimal so nothing is competing for resources. I also don't do any graphics intensive stuff on the VM. Mainly just test websites and simple programs to make sure they actually run properly on windows.

Thanks for the info, going to test my settings and also tweaking the system a bit more.
I know GPU performance is still work in progress, also going to test with EXT4/XFS.

Could you tell me a bit more about your config? Like what flags to your use for booting (VM related, like intel_iommu=on) and what modules you have enabled?
I think I will stick to libvirt, but still want to use QEMU without any managers.

Many thanks!

Arch Linux

#1 2016-03-05 21:44:31

What VM performance should I expect with my PC?

#2 2016-03-05 22:06:39

Re: What VM performance should I expect with my PC?

#3 2016-03-05 22:30:13

Re: What VM performance should I expect with my PC?

#4 2016-03-05 22:46:25

Re: What VM performance should I expect with my PC?

#5 2016-03-08 18:19:31

Re: What VM performance should I expect with my PC?

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