Virtualization In Linux Kernel 2.6.20

mcalwell writes with an article about the Kernel-based Virtual Machine (or KVM for short) in the release candidate Linux 2.6.20 kernel. From the article: "[T]he Linux 2.6.20 kernel will include a full virtualization (not para-virtualization) solution. [KVM] is a GPL software project that has been developed and sponsored by Qumranet. In this article we are offering a brief overview of the KVM for Linux as well as offering up in-house performance numbers as we compare KVM to other virtualization solutions such as QEMU Accelerator and Xen."

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Performance Comparisons

[EvanED]

Why no comparison against VMWare or native?

(VMWare I can kind of see, if they were deliberately sticking to all free solutions, but no comparison to running on the host system? That's just bad reporting IMO.)

Apples to Oranges

[X0563511]

So... we can compare Xen and KVM to Qemu now? The next time nVidia updates their drivers we should benchmark them against MESA OpenGL...

Xen amd KVM utilize (require, if I remember correctly) support for virtualization-specific processor instructions. Qemu does not.

VMWare performs better - heres why

[Anonymous Coward]

VMWare will perform *much* better on any workload with heavy process thrashing, especially forking (such as the lame compilation or anything that does an autoconf configure and make). This is due to the Intel and AMD virtualization extensions not going far enough to handle unix style OS workloads well (hardware assisted MMU and/or TLB virtualization support is lacking). Context switching takes a heavy toll. Windows doesn't do it so much so it won't suffer as much.

Also, only AMD's SVM supports full-virtualization of x86_64. Intel doesn't implement that.

VMWare works by dynamically scanning/translating native x86 and x86_64 code for protected instructions before executing it so it does not need the hardware extensions to work. That also means vmware performs better by not using the new cpu features.

Re:KVM name is misleading

[Jessta]

3 ? 00:00:00 ksoftirqd/0
        5 ? 00:00:00 khelper
        6 ? 00:00:00 kthread
        8 ? 00:00:00 kblockd/0
        9 ? 00:00:00 kacpid
    102 ? 00:00:00 kseriod
    105 ? 00:00:00 khubd
    176 ? 00:00:00 kswapd0
    784 ? 00:00:00 kpsmoused
    814 ? 00:00:00 khpsbpkt
    818 ? 00:00:00 knodemgrd_0

seems to fit in with the naming convention of all the kernel related processes.

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KVM, QEMU, and Qemudo

[this great guy]

This is likely to boost QEMU's popularity, the virtualizer accelerated by KVM. An interesting coïncidence is that I released the very first version of Qemudo [sourceforge.net] on Jan 4th while being totally unaware of the existence of KVM. Then three days later the KVM project released their first version too, and I read about it on this kerneltrap article [kerneltrap.org].

I am thrilled at the idea of using KVM + QEMU + Qemudo together. To put it simply, and to quote my README, Qemudo is "a Web interface to QEMU offering a way for users to access and control multiple virtual machines running on one or more remote physical machines." Qemudo makes use of two important features in QEMU: native support of VNC, and copy-on-write disk images for instantaneous VM creation. If you are interested go check out the website (and download the tarball which contains more detailled doc). </shameless-plug>

Re:Mod... Parent... Up

[Anonymous Coward]

Just use Solaris. You get to run all the Lunix source and binaries and all the Solaris ones too, the ABI is stable over many years and it has many more useful feaures than Lunix. Also the virtualisation stuff has been in Solaris a lot longer. Oh, and it handles SMP and NUMA better, and it has ZFS.

Re:Mod me down!

[Bert64]

I heard that the vmware license specifically excludes rights to benchmark it, or at least to publish those benchmarks.

benchmarks

[Jacek Poplawski]

Benchmarks in the article shows that it is slower than XEN.
Do you know why?
Xen requires some support from virtualized operating system, what about KVM?