performance Archives - Heiko's Blog

Impact of Spectre and Meltdown Protection on Virtual Machine Performance

A year ago I wrote about the 2D graphics performance impact of the Windows 10 (1803) update inside a virtual machine. As it turned out, the performance impact was related to the Spectre vulnerability patch that Microsoft had introduced. However, the same patch had practically no performance impact on a Windows 10 bare-metal installation.

Time has passed and I wanted to see if there has been any progress. Right now I’m running Windows 10 (1903) with Nvidia driver release 431.36. Windows 10 is up-to-date, Nvidia however already offers a newer version (431.60).

Tuning VM Disk Performance

Qemu/kvm provides you with a plethora of ways to configure your storage devices. Yet no other type of device shows such a variance in its performance, with disk I/O throughput anywhere from stellar to abysmal using the very same hardware.

In this post I like to show some configuration options that can help improve VM disk performance. For an in-depth presentation on the latest developments and features, with hands-on examples, see Storage Performance Tuning for FAST! Virtual Machines.

Creating a Windows 10 Virtual Machine Using the Virtual Machine Manager (virt-manager)

March 29. 2020 edit: Recently I published a tutorial using Virtual Machine Manager. You can find it here: Creating a Windows 10 VM on the AMD Ryzen 9 3900X using Qemu 4.0 and VGA Passthrough.

Before you get your hopes high, this post is not (yet?) a tutorial on creating a Windows 10 virtual machine using the Virtual Machine Manager (virt-manager) GUI. It should have been, though. I spent the better part of a week trying to configure and install a Windows 10 VM that delivers the performance that I’m used to.

As it turns out, it was a failure. Don’t get me wrong, I did manage to configure and run Windows using virt-manager and virsh. I even installed it multiple times, changing the configuration to what I hoped would improve performance. But whatever I tried, I never got even near the speed and snappiness that I achieve by following my tutorial using a start script.

Many users – myself included – rather prefer the comfort of a graphical user interface with check boxes and pull-down menus to select the various options. I’ve listed some tutorials using the virt-manager at the end, for those who came to find a solution.

Upgrade to Linux Mint 19 – Windows 10 VM Benchmark

I just upgraded my Linux Mint Mate 18.3 installation to Linux Mint Mate 19, using the mintupgrade utility. It required some manual fixes, but all in all it went smooth.

Below the first UserBenchmark using Linux Mint 19 with updated qemu/kvm packages:

UserBenchmarks: Game 60%, Desk 76%, Work 67%
CPU: Intel Core i7-3930K – 86.8%
GPU: Nvidia GTX 970 – 58.5%
SSD: Red Hat VirtIO 140GB – 72.1%
HDD: Red Hat VirtIO 2.5TB – 87.1%
HDD: Red Hat VirtIO 2TB – 51.7%
RAM: QEMU 1x16GB – 77.3%
MBD: QEMU Standard PC (Q35 + ICH9, 2009)

Prime95 Benchmark: Linux Host versus Windows VM

This is yet another benchmark of my Windows 10 VM. This time I used the free Mersenne Prime Search software Prime95 (mprime under Linux) available at www.mersenne.org. I wanted to see if there is a significant difference between running the benchmark on the Linux host, versus the Windows virtual machine.

Why run Windows on Linux?

Last edited: May 31, 2020

I’ve written several tutorials on “how to make dual-boot obsolete using VGA passthrough“, yet one may ask why run Windows on Linux? Most PC or laptop come pre-installed with Windows, in fact its rare to see computers pre-installed with Linux. So why not just leave Windows and install Linux in a virtual machine (VM), for example using Oracle VirtualBox?

Installing Linux in a VirtualBox VM is definitely a lot easier than following my tutorials on VGA passthrough (VFIO). Not only that, most computer users who want or need to use both Windows and Linux will find that this simple solution is all they need.