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 00:56:51 +0300 Message-ID: <4C69B423.7070306@redhat.com> References: <4C699645.70209@redhat.com> <4C69AF08.6010504@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]:27854 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751956Ab0HPV4z (ORCPT ); Mon, 16 Aug 2010 17:56:55 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 08/17/2010 12:51 AM, Alex Rixhardson wrote: > I tried with 'notsc divider=10' (since it's 64 bit guest), but the > results are the still same :-(. The guest is idle at the time of > testing. It has 2 CPU and 1024 MB RAM available. Hmm, are you using e1000 or virtio for the 4.5 guest? e1000 should be slow since it's less suitable for virtualization (3 mmio/packet) > > On Mon, Aug 16, 2010 at 11:35 PM, Dor Laor wrote: >> 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 >> >> > -- > 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