On Thu, 2011-02-24 at 11:07 -0600, C Anthony Risinger wrote: > On Thu, Feb 24, 2011 at 10:53 AM, Jelle van der Waa <jelle@xxxxxxxx> wrote: > > On Thu, 2011-02-24 at 10:33 -0600, C Anthony Risinger wrote: > >> On Wed, Feb 23, 2011 at 7:38 PM, Allan McRae <allan@xxxxxxxxxxxxx> wrote: > >> > > >> > If this is virtualbox specific, I'd try qemu-kvm. > >> > >> hey, > >> > >> i was just trying to get a concrete answer about this the other day, > >> so maybe you can clarify because i keep reading conflicting and/or > >> outdated information. > >> > >> AFAICS, qemu-kvm is still _different_ from upstream kvm support in > >> qemu, correct? i tried rebuilding qemu several times, ensuring i had > >> all the options i wanted (SPICE/kvm/etc) and i was getting absolutely > >> <expletive deleted> performance -- switch to qemu-kvm and she's > >> blazing again, yet many places seem to suggest they are one and the > >> same. > >> > >> i see they definitely have different sources, but would you/anyone > >> care to elaborate on the relationship? > > > > IIRC > > > > qemu-kvm is the QEMU + KVM provided by the kvm project and normal QEMU > > can use KVM as virtualizer. (correct me if i am wrong ) > > > > from wikipedia: > > By itself, KVM does not perform any emulation. Instead, a > > user-space program uses the /dev/kvm interface to set up the > > guest VM's address space, feeds it simulated I/O and maps its > > video display back onto the host's. At least two programs > > exploit this feature: a modified version of Qemu, and Qemu > > itself since version 0.10.0. > > > > In short, if you have VT extensions, use qemu-kvm, if not use qemu since > > it emulates ( costs much cpu though ). > > > > QEMU/KVM is for me the best way to run windows, KVM is in the kernel so > > now rebuilding of modules, completely open source and it has nice > > features. > > hmm, soo qemu doesn't actually use the VT extensions? wtf is the > point then? QEMU is an emulator -> so for ARM for example > this is what i don't understand; if qemu supports KVM via > the `-enable-kvm` switch why does it suck so much -- it seems just as > slow to me as no KVM support at all. Here it's not, are you using qemu-kvm or some selfcompiled version? > I have a server that runs > several KVM/libvirt instances (windows being one of them purely for > ... i dont even know) so i'm pretty familiar with it all, but i'm just > trying to get solid info why there is such a huge performance gap when > the both "use KVM". i thought KVM itself did all the VT handling. > > C Anthony Another tip for kvm usage is installing your OS on virtio [1] [1] http://www.linux-kvm.org/page/Using_VirtIO_NIC -- Jelle van der Waa
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