From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe Subject: less cores more iops / speed Date: Wed, 07 Nov 2012 23:02:18 +0100 Message-ID: <509ADA6A.9000807@profihost.ag> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.profihost.ag ([85.158.179.208]:44903 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753462Ab2KGWCV (ORCPT ); Wed, 7 Nov 2012 17:02:21 -0500 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: "ceph-devel@vger.kernel.org" Hello again, I've noticed something really interesting. I get 5000 iops / VM for rand. 4k writes while assigning 4 cores on a 2.5 Ghz Xeon. When i move this VM to another kvm host with 3.6Ghz i get 8000 iops (still 8 cores) when i then LOWER the assigned cores from 8 to 4 i get 14.500 iops. If i assign only 2 cores i get 16.000 iops... Why does less kvm cores mean more speed? Greets, Stefan