Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751648Ab2KPLrH (ORCPT ); Fri, 16 Nov 2012 06:47:07 -0500 Received: from gwu.lbox.cz ([62.245.111.132]:39410 "EHLO gwu.lbox.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751231Ab2KPLrG (ORCPT ); Fri, 16 Nov 2012 06:47:06 -0500 Date: Fri, 16 Nov 2012 12:47:03 +0100 From: Nikola Ciprich To: linux-kernel mlist Cc: nik@linuxbox.cz Subject: strange values of loadavg and nr of io-blocked tasks Message-ID: <20121116114703.GA8634@pcnci.linuxbox.cz> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="mYCpIKhGyMATD0i+" Content-Disposition: inline User-Agent: Mutt/1.5.21 (2011-07-01) X-Antivirus: on lbxovapx by Kaspersky antivirus, 8074727 records (last update: 20121116) X-Spam-Score: N/A (imported whitelist) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1628 Lines: 58 --mYCpIKhGyMATD0i+ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, I was doing some I/O tuning of our KVM host, and noticed some strange behaviour. When I start some heavy I/O load on guest (ie run some fio benchmark), loadavg value of the host jumps to value about 65 and holds until load ends. sar reports similar number of blocked tasks. I don't really understand those numbers, because only active tasks are 4 qemu-kvm threads and few other sleeping tasks (so none in R or D state). is it possible to somehow find which tasks seem to be blocked? or why is loadavg value so high? the system is x86_64 quad core with 4GB RAM running centos 6 with 3.0.52-rc= 1 kernel. Thanks a lot in advance for any answer BR nik --=20 ------------------------------------- Ing. Nikola CIPRICH LinuxBox.cz, s.r.o. 28.rijna 168, 709 00 Ostrava tel.: +420 591 166 214 fax: +420 596 621 273 mobil: +420 777 093 799 www.linuxbox.cz mobil servis: +420 737 238 656 email servis: servis@linuxbox.cz ------------------------------------- --mYCpIKhGyMATD0i+ Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (GNU/Linux) iEYEARECAAYFAlCmJ7cACgkQ3xdJJrLygV5BvgCfcKJAWOafvYw14qwrF/Dqa2gp 9N0An1hVO0yjcmaGa5C1J1UbK/6yflEK =DzVH -----END PGP SIGNATURE----- --mYCpIKhGyMATD0i+-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/