From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56588) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XikDT-0005Nf-G6 for qemu-devel@nongnu.org; Mon, 27 Oct 2014 09:20:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XikDN-0001ag-Bc for qemu-devel@nongnu.org; Mon, 27 Oct 2014 09:20:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34813) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XikDN-0001WP-58 for qemu-devel@nongnu.org; Mon, 27 Oct 2014 09:20:05 -0400 Date: Mon, 27 Oct 2014 13:19:58 +0000 From: Stefan Hajnoczi Message-ID: <20141027131958.GC15071@stefanha-thinkpad.redhat.com> References: <20141024090406.GA32480@stefanha-thinkpad.redhat.com> <884af3f3-d7fc-4080-8c54-09384314e006@mailpro> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="i7F3eY7HS/tUJxUd" Content-Disposition: inline In-Reply-To: <884af3f3-d7fc-4080-8c54-09384314e006@mailpro> Subject: Re: [Qemu-devel] is it possible to use a disk with multiple iothreads ? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexandre DERUMIER Cc: josh durgin , qemu-devel --i7F3eY7HS/tUJxUd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 24, 2014 at 03:39:52PM +0200, Alexandre DERUMIER wrote: > >>Regarding Ceph, do you know why it burns a lot of CPU? >=20 > I'm currently doing some perfs to find why is so huge. >=20 > One thing is that qemu+ qemu rbd block driver + librbd seem to use 2-3x m= ore cpu, than passing krbd /dev/rbd0 from host to qemu. > Don't known yet if the problem is librbd or qemu rbd block driver. That's very interesting! Please keep Josh and me in CC when you want to discuss the results. Stefan --i7F3eY7HS/tUJxUd Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJUTkZ9AAoJEJykq7OBq3PINzAH/2zDkV+vIc9VXJILC3TQYlWZ Tj8HkdtJQKmPn1UldXK1NOQlYYchPIph7YxFWxKLuX9zLwSZ3Y2XTGYMju3E5Zhj lTNr4zYJuo/HFpV0Iem3CVBKBm2kz7ZfU1V5us/kIBb2qnZGBTpNZfLSfCgzHalW 4R6EObhgw11PTeulcHLRl7b0IkKWxD2JkJY3bXfxf+FRdeInAY92OWp64G9AvlSP yjRb75E44ylzC13lRUqArk3fJNQjkErCt7jQxiwfHvuZbI5HuYtIaddlUVEC9Shd +4V6RwvBVkb0LavTC6lXY5UKAbMd7zVUDa4wsb5+G5D1hzgfRKTonT33gWnJ+Z8= =82Pt -----END PGP SIGNATURE----- --i7F3eY7HS/tUJxUd--