> From: libvirt-users-request@redhat.com
> Subject: libvirt-users Digest, Vol 40, Issue 24
> To: libvirt-users@redhat.com
> Date: Wed, 10 Apr 2013 12:00:18 -0400
>
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> Today's Topics:
>
> 1. performance tradeoffs/penalty (lejeczek)
> 2. Re: performance tradeoffs/penalty (Felicitus)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 10 Apr 2013 13:02:19 +0100
> From: lejeczek <peljasz@yahoo.co.uk>
> To: libvirt-users@redhat.com
> Subject: [libvirt-users] performance tradeoffs/penalty
> Message-ID: <516554CB.2000703@yahoo.co.uk>
> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>
> hi everybody
>
> a newbie here, hoping some experienced users/expert can
> honestly answer this one question,
> and I think I realize all other advantages libvirtoffer but
> simply performance,
>
> does libvirt make a user pay penalty, even if only a small
> amount, for using it when compared to raw qemu-kvm command line?
> if it does where the overhead goes? quest or host, or maybe
> both?
> lastly
> if overall performance is slower then how small it is
> comparing to all the advantages it offers?
>
> many thanks
> and apologies if this subject was answered already in the past
>
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> ------------------------------
>
> Message: 2
> Date: Wed, 10 Apr 2013 14:45:02 +0200
> From: Felicitus <felicitus@felicitus.org>
> To: libvirt-users@redhat.com
> Subject: Re: [libvirt-users] performance tradeoffs/penalty
> Message-ID: <51655ECE.20503@felicitus.org>
> Content-Type: text/plain; charset=ISO-8859-1
>
> > does libvirt make a user pay penalty, even if only a small amount, for
> > using it when compared to raw qemu-kvm command line?
>
> Not that I know of, except that the libvirt daemon uses a few additional
> CPU cycles. Technically yes, in the spirit of the question no. Have a
> look at your process tree; you'll see command lines in the same way as
> you'd expect them to be when you start machines manually.
>
> > if it does where the overhead goes? quest or host, or maybe both?
>
> No additional CPU cycles for the guest, a few additional CPU cycles for
> the host to get status information and expose it via the daemon.
>
> > if overall performance is slower then how small it is comparing to all
> > the advantages it offers?
>
> It is completely negligible.
>
> Felicitus
>
>
>
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> End of libvirt-users Digest, Vol 40, Issue 24
> *********************************************