From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dor Laor Subject: Re: RHEL 4.5 guest virtual network performace Date: Tue, 17 Aug 2010 00:35:04 +0300 Message-ID: <4C69AF08.6010504@redhat.com> References: <4C699645.70209@redhat.com> Reply-To: dlaor@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Alex Rixhardson Return-path: Received: from mx1.redhat.com ([209.132.183.28]:36499 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754693Ab0HPVfJ (ORCPT ); Mon, 16 Aug 2010 17:35:09 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 08/17/2010 12:22 AM, Alex Rixhardson wrote: > Thanks for the suggestion. > > I tried with the netperf. I ran netserver on host and netperf on RHEL > 5.5 and RHEL 4.5 guests. This are the results of 60 seconds long > tests: > > RHEL 4.5 guest: > Throughput (10^6bits/sec) = 145.80 At least it bought you another 5Mb/s over iperf ... It might be time related, 5.5 has kvmclock but rhel4 does not. If it's 64 bit guest add this to the 4.5 guest cmdline 'notsc divider=10'. If it's 32 use 'clock=pmtmr divider=10'. The divider is probably new and is in rhel4.8 only, it's ok w/o it too. What's the host load for the 4.5 guest? > > RHEL 5.5 guest: > Throughput (10^6bits/sec) = 3760.24 > > The results are really bad on RHEL 4.5 guest. What could be wrong? > > Regards, > Alex > > On Mon, Aug 16, 2010 at 9:49 PM, Dor Laor wrote: >> On 08/16/2010 10:00 PM, Alex Rixhardson wrote: >>> >>> Hi guys, >>> >>> I have the following configuration: >>> >>> 1. host is RHEL 5.5, 64bit with KVM (version that comes out of the box >>> with RHEL 5.5) >>> 2. two guests: >>> 2a: RHEL 5.5, 32bit, >>> 2b: RHEL 4.5, 64bit >>> >>> If I run iperf between host RHEL 5.5 and guest RHEL 5.5 inside the >>> virtual network subnet I get great results (> 4Gbit/sec). But if I run >>> iperf between guest RHEL 4.5 and either of the two RHELs 5.5 I get bad >>> network performance (around 140Mbit/sec). >> >> Please try netperf, iperf known to be buggy and might consume cpu w/o real >> justification >> >>> >>> The configuration was made thru virtual-manager utility, nothing >>> special. I just added virtual network device to both guests. >>> >>> Could you guys give me some tips on what should I check? >>> >>> Regards, >>> Alex >>> -- >>> To unsubscribe from this list: send the line "unsubscribe kvm" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html