From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chegu Vinod Subject: Networking performance on a KVM Host (with no guests) Date: Thu, 19 Apr 2012 03:53:39 +0000 (UTC) Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from plane.gmane.org ([80.91.229.3]:59651 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752020Ab2DSDxu (ORCPT ); Wed, 18 Apr 2012 23:53:50 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1SKiRI-00031s-OD for kvm@vger.kernel.org; Thu, 19 Apr 2012 05:53:49 +0200 Received: from zcce02cs1747-db20.houston.hp.com ([15.203.233.84]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 19 Apr 2012 05:53:48 +0200 Received: from chegu_vinod by zcce02cs1747-db20.houston.hp.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 19 Apr 2012 05:53:48 +0200 Sender: kvm-owner@vger.kernel.org List-ID: Hello, Perhaps this query was answered in the past. If yes kindly point me to the same. We noticed differences in networking performance (measured via netperf over a 10G NIC) on an X86_64 server between the following two configurations : 1) Server run as a KVM Host (but with no KVM guests created on it (or) no extra bridges created other than the default vibr0 bridge) vs. 2) The same server running the same version of Linux but without any of the virtualization software installed on it. Config #2 performed much better ! Is this expected ? What are the reasons behind this ? Is there any way to gain back the loss in performance on the KVM host without having to uninstall the virtualization software (i.e. in Config 1). Thanks! Vinod