Linux KVM Continues Offering Much Better Performance Than VirtualBox

[emblemparade]

I use both quite a lot, but as a developer doing a mix of frontend and backend work on various operating systems I tend to prefer VirtualBox due to so many ease-of-use-features: nice management GUI allowing easy connection/disconnection of USB and other devices, powerful guest additions with support for screen resizing and shared clipboards, automatically sets up remote access, etc. It's just really nice for everyday virtualization needs. Performance isn't always a high priority, depending on what you're doing.

I do wish the KVM/QEMU world would be able to match VirtualBox better feature to feature. Still, happy to have both.

BTW, as others have pointed out, VirtualBox uses KVM as hypervisor by default on Linux, so the title is a bit misleading. The comparison is specifically about the libvirt-packaged KVM/QEMU vs. VirtualBox.

Generally, Michael, you can do a better job at describing and explaining the setups for your benchmarks. Almost always you get questions in the comments about whether you used feature X or Y and why.

[andoride]

Impressive performance for KVM, a shame getting it up and running is so hard.

have you tried virt-manager?

[andoride]

Is also possible to increase KVM performance using static cpu "pinning" for avoiding overhead on context switching in the host and also hugemem should help.
I think VirtualBox is great because is easy to use and also tools like vagrant use VirtualBox as default.

[varikonniemi]

Impressive performance for KVM, a shame getting it up and running is so hard.

[Berniyh]

Mmm... But in System->Acceleration->Paravirtualization Interface you can choose between: Default, Inherited, Minimal, Hyper-V and KVM... Does it have something to do with allowing to use KVM under the hood, or it is something else?

My post above gives you all the answers you need.

[rastersoft]

No. It has its own hypervisor which had existed long before KVM got released.

Mmm... But in System->Acceleration->Paravirtualization Interface you can choose between: Default, Inherited, Minimal, Hyper-V and KVM... Does it have something to do with allowing to use KVM under the hood, or it is something else?

[geearf]

No. It has its own hypervisor which had existed long before KVM got released.

Is there any special benefit to it?

[birdie]

Doesn't VirtualBox also uses KVM on Linux? So it's more like VirtualBox vs QEMU.

No. It has its own hypervisor which had existed long before KVM got released.

[Berniyh]

Did you set Paravirtualization Interface to KVM and enabled HW virtualization in Virtuabox settings?

If I understand the documentation correctly, this should be done automatically and actually it doesn't quite do what you think it does.

https://www.virtualbox.org/manual/ch...l#gimproviders
Oracle VM VirtualBox enables the exposure of a paravirtualization interface, to facilitate accurate and efficient execution of software within a virtual machine. These interfaces require the guest operating system to recognize their presence and make use of them in order to leverage the benefits of communicating with the Oracle VM VirtualBox hypervisor.

Most modern mainstream guest operating systems, including Windows and Linux, ship with support for one or more paravirtualization interfaces. Hence, there is typically no need to install additional software in the guest to take advantage of this feature.

Exposing a paravirtualization provider to the guest operating system does not rely on the choice of host platforms. For example, the Hyper-V paravirtualization provider can be used for VMs to run on any host platform supported by Oracle VM VirtualBox and not just Windows.

Oracle VM VirtualBox provides the following interfaces:

• Minimal: Announces the presence of a virtualized environment. Additionally, reports the TSC and APIC frequency to the guest operating system. This provider is mandatory for running any Mac OS X guests.

• KVM: Presents a Linux KVM hypervisor interface which is recognized by Linux kernels version 2.6.25 or later. Oracle VM VirtualBox's implementation currently supports paravirtualized clocks and SMP spinlocks. This provider is recommended for Linux guests.

• Hyper-V: Presents a Microsoft Hyper-V hypervisor interface which is recognized by Windows 7 and newer operating systems. Oracle VM VirtualBox's implementation currently supports paravirtualized clocks, APIC frequency reporting, guest debugging, guest crash reporting and relaxed timer checks. This provider is recommended for Windows guests.

VBoxManager doc also says that KVM is the default for Linux and hyperv is the default for Windows:

--paravirtprovider none|default|legacy|minimal|hyperv|kvm: Specifies which paravirtualization interface to provide to the guest operating system. Specifying none explicitly turns off exposing any paravirtualization interface. The option default selects an appropriate interface when starting the VM, depending on the guest OS type. This is the default option chosen when creating new VMs. The legacy option is used for VMs which were created with older Oracle VM VirtualBox versions and will pick a paravirtualization interface when starting the VM with Oracle VM VirtualBox 5.0 and newer. The minimal provider is mandatory for Mac OS X guests. kvm and hyperv are recommended for Linux and Windows guests respectively. These options are explained in Section 11.4, “Paravirtualization Providers”.

[equeim]

Doesn't VirtualBox also uses KVM on Linux? So it's more like VirtualBox vs QEMU.