From: Avi Kivity <avi@redhat.com>
To: Erik Jacobson <erikj@sgi.com>
Cc: kvm@vger.kernel.org
Subject: Re: slow guest performance with build load, looking for ideas
Date: Sun, 14 Jun 2009 12:33:06 +0300 [thread overview]
Message-ID: <4A34C3D2.9020009@redhat.com> (raw)
In-Reply-To: <20090612210443.GA21840@sgi.com>
Erik Jacobson wrote:
> We have been trying to test qemu-kvm virtual machines under an IO load.
> The IO load is quite simple: A timed build of the linux kernel and modules.
> I have found that virtual machines take more than twice as long to do this
> build as the host. It doesn't seem to matter if I use virtio or not, Using
> the same device and same filesystem, the host is more than twice as fast.
>
> We're hoping that we can get some advice on how to address this issue. If
> there are any options I should add for our testing, we'd appreciate it. I'm
> also game to try development bits to see if they make a difference. If it
> turns out "that is just the way it is right now", we'd like to know that
> too.
>
> For these tests, I used Fedora 11 as the virtualization server. I did this
> because it has recent bits. I experimented with SLES11 and Fedora11 guests.
>
> In general, I used virt-manager to do the setup and launching. So the
> qemu-kvm command lines are based on that (and this explains why they are
> a bit long). I then modified the qemu-kvm command line to perform other
> variations of the test. Example command lines can be found at the end of
> this message.
>
> I performed tests on two different systems to be sure it isn't related to
> specific hardware.
>
What is the host cpu type? On pre-Nehalem/Barcelona processors kvm has
poor scalability in mmu intensive workloads like kernel builds.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2009-06-14 9:33 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-12 21:04 slow guest performance with build load, looking for ideas Erik Jacobson
2009-06-14 9:33 ` Avi Kivity [this message]
2009-06-15 14:15 ` Erik Jacobson
2009-06-15 14:24 ` Avi Kivity
2009-06-15 15:25 ` Michael Tokarev
2009-06-15 15:27 ` Avi Kivity
2009-06-16 7:03 ` Michael Tokarev
2009-06-16 8:07 ` Avi Kivity
2009-06-18 23:07 ` Erik Jacobson
2009-06-28 14:17 ` Avi Kivity
2009-06-28 19:05 ` Erik Jacobson
2009-06-28 21:28 ` Avi Kivity
2009-07-01 21:41 ` Erik Jacobson
2009-07-02 5:48 ` Avi Kivity
2009-07-02 9:41 ` Avi Kivity
2009-07-03 15:43 ` Mark McLoughlin
2009-07-03 16:28 ` Erik Jacobson
2009-07-09 2:36 ` Erik Jacobson
2009-07-09 7:48 ` Avi Kivity
2009-07-09 18:01 ` Erik Jacobson
2009-07-12 8:38 ` Avi Kivity
2009-07-16 12:20 ` Jes Sorensen
2009-07-25 14:33 ` Avi Kivity
2009-07-03 10:41 ` Matty
2009-07-05 8:07 ` Avi Kivity
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