From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Blake Subject: Re: [libvirt-users] Kernel unresponsive after booting 700+ vm's on a single host Date: Mon, 10 Sep 2012 11:42:15 -0600 Message-ID: <504E2677.9070006@redhat.com> References: <827B80946D30E94D88703E3075B6FE7E13E5615D@ExMbx-02.ada.hioa.no> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig68CD1D0365B81B37FBAEB5C6" Cc: "libvirt-users@redhat.com" , "kvm@vger.kernel.org" To: Alfred Bratterud Return-path: Received: from mx1.redhat.com ([209.132.183.28]:62773 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750891Ab2IJRmb (ORCPT ); Mon, 10 Sep 2012 13:42:31 -0400 In-Reply-To: <827B80946D30E94D88703E3075B6FE7E13E5615D@ExMbx-02.ada.hioa.no> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig68CD1D0365B81B37FBAEB5C6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 09/10/2012 07:51 AM, Alfred Bratterud wrote: > For a research project we are trying to boot a very large amount of tin= y, custom built VM's on KVM/ubuntu. The maximum VM-count achieved was 100= 0, but with substantial slowness, and eventually kernel failure, while th= e cpu/memory loads were nowhere near limits. Where is the likely bottlene= ck? Any solutions, workarounds, hacks or dirty tricks? Are you using cgroups? There have been some known bottlenecks in the kernel cgroup code, where it scales very miserably; and since libvirt uses a different cgroup per VM by default when cgroups are enabled, that might explain part of the problem. Other than that, if you can profile the slowdowns, I'm sure people would be interested in the results. --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enig68CD1D0365B81B37FBAEB5C6 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQEcBAEBCAAGBQJQTiZ3AAoJEKeha0olJ0NqBHwH/RoD6zQxLz8hfvreZZR2Dd2/ yrEx0qUvFktHPkxUmk3bfk1TohDEluE5XuouqcewE3NCPPm/MIPQPbbNSAnvRBSz xGIgmrczntQksDxBR76pDMVba3V4xQHmf4CFciVu/WmeSGlpH96R42nPAjBe9Fzg DNF1AMKTHxpSVNlbYAVeoFDeiVyMsV82mp7HE4ZKpbLF6U4iZ5FjCBABfFge9gGS 6kU+frwy5SZPQjkfy/IdMAyB6b+SsEkpg32jMkVSq2Lzc48xg11AAhc6SMMlwrrb tqX3/qAf58qgro1G6sqrctFxBYivBkkSCg/rZb+keBA1YOD7Jg5oBnZcCvEbq8g= =Gr/x -----END PGP SIGNATURE----- --------------enig68CD1D0365B81B37FBAEB5C6--