From: Paolo Bonzini <pbonzini@redhat.com>
To: Alexandre DERUMIER <aderumier@odiso.com>,
Stefan Hajnoczi <stefanha@redhat.com>
Cc: josh durgin <josh.durgin@inktank.com>,
qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] is it possible to use a disk with multiple iothreads ?
Date: Mon, 27 Oct 2014 15:47:19 +0100 [thread overview]
Message-ID: <544E5AF7.2030106@redhat.com> (raw)
In-Reply-To: <33a4db31-a5e2-4bfc-b73b-c0e7d3023542@mailpro>
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 the 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
next prev parent reply other threads:[~2014-10-27 14:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <391d6bb1-e0ad-49ea-afdc-fff462081f24@mailpro>
2014-10-23 18:26 ` [Qemu-devel] is it possible to use a disk with multiple iothreads ? Alexandre DERUMIER
2014-10-24 9:04 ` Stefan Hajnoczi
2014-10-24 13:39 ` Alexandre DERUMIER
2014-10-27 13:19 ` Stefan Hajnoczi
2014-10-27 14:13 ` Alexandre DERUMIER
2014-10-27 14:47 ` Paolo Bonzini [this message]
2014-10-27 16:42 ` Alexandre DERUMIER
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