>>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" <pbonz...@redhat.com> À: "Alexandre DERUMIER" <aderum...@odiso.com>, "Stefan Hajnoczi" <stefa...@redhat.com> Cc: "josh durgin" <josh.dur...@inktank.com>, "qemu-devel" <qemu-devel@nongnu.org> Envoyé: 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 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
