From: Dor Laor <dlaor@redhat.com>
To: Alex Rixhardson <alexrixhardson@gmail.com>
Cc: kvm@vger.kernel.org
Subject: Re: RHEL 4.5 guest virtual network performace
Date: Tue, 17 Aug 2010 00:35:04 +0300 [thread overview]
Message-ID: <4C69AF08.6010504@redhat.com> (raw)
In-Reply-To: <AANLkTikkMFddsbBqxNG0=vXXHryN7YnvDnozeiE6Yb=G@mail.gmail.com>
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<dlaor@redhat.com> 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
>>> --
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>>
>>
> --
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next prev parent reply other threads:[~2010-08-16 21:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-16 19:00 RHEL 4.5 guest virtual network performace Alex Rixhardson
2010-08-16 19:49 ` Dor Laor
2010-08-16 21:22 ` Alex Rixhardson
2010-08-16 21:35 ` Dor Laor [this message]
2010-08-16 21:51 ` Alex Rixhardson
2010-08-16 21:56 ` Dor Laor
2010-08-16 22:05 ` Alex Rixhardson
2010-08-16 23:09 ` Alex Rixhardson
2010-08-17 1:22 ` David S. Ahern
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