From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:46413)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <aderumier@oxygem.tv>) id 1XinNb-000328-EG
	for qemu-devel@nongnu.org; Mon, 27 Oct 2014 12:42:55 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <aderumier@oxygem.tv>) id 1XinNX-0000ti-8H
	for qemu-devel@nongnu.org; Mon, 27 Oct 2014 12:42:51 -0400
Received: from mailpro.odiso.net ([89.248.209.98]:59991)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <aderumier@oxygem.tv>) id 1XinNX-0000tZ-3K
	for qemu-devel@nongnu.org; Mon, 27 Oct 2014 12:42:47 -0400
Date: Mon, 27 Oct 2014 17:42:36 +0100 (CET)
From: Alexandre DERUMIER <aderumier@odiso.com>
Message-ID: <9e233c9e-27fc-4ba6-897d-79ce189340d0@mailpro>
In-Reply-To: <544E5AF7.2030106@redhat.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Subject: Re: [Qemu-devel] is it possible to use a disk with multiple
	iothreads ?
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: josh durgin <josh.durgin@inktank.com>, qemu-devel <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>

>>You are missing debug information unfortunately, 

Ok thanks, I'll try to add qemu debug symbols.

(I have already libc6,librbd,librados debug symbols installed)

----- Mail original ----- 

De: "Paolo Bonzini" <pbonzini@redhat.com> 
=C3=80: "Alexandre DERUMIER" <aderumier@odiso.com>, "Stefan Hajnoczi" <stef=
anha@redhat.com> 
Cc: "josh durgin" <josh.durgin@inktank.com>, "qemu-devel" <qemu-devel@nongn=
u.org> 
Envoy=C3=A9: Lundi 27 Octobre 2014 15:47:19 
Objet: Re: is it possible to use a disk with multiple iothreads ? 



On 10/27/2014 03:13 PM, Alexandre DERUMIER wrote: 
>>> That's very interesting! Please keep Josh and me in CC when you want to=
 
>>> >>discuss the results. 
> Here the aggregate results (perf report details attached in this mail) 
> 
> + 33,02% 3974368751 kvm [kernel.kallsyms] 
> + 23,66% 2847206635 kvm libc-2.13.so 
> + 18,79% 2262052133 kvm librados.so.2.0.0 
> + 11,04% 1328581527 kvm librbd.so.1.0.0 
> + 5,87% 706713737 kvm libpthread-2.13.so 
> + 3,75% 451690142 kvm kvm 
> + 2,74% 329457334 kvm libstdc++.so.6.0.17 
> + 0,51% 61519664 kvm [vdso] + 0,42% 50000089 kvm libglib-2.0.so.0.3200.4 =
+ 0,15% 18119658 kvm libm-2.13.so + 0,05% 5705776 kvm librt-2.13.so + 0,00%=
 356625 kvm libz.so.1. 
2.7 
> 
> 
> 
> 
>>> >> 23,66% 2847206635 kvm libc-2.13.so 
> This one is mostly malloc,free,... 
> 
> 
> I see almost same results using fio with rbdengine on the host (outside t=
he kvm process). 
> So I think they are all mostly related to librbd. 

You are missing debug information unfortunately, but the slowdown seems 
to be related to futexes. 

Paolo