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xen-devel
Re: [Xen-devel] Network performance - sending from VM to VM using TCP
Are you using FreeBSD or Linux?
On Thu, 26 May 2005, Cherie Cheung wrote:
> Hi,
>
> I have been simulating a network using dummynet and evaluating it
> using netperf. Xen3.0-unstable is used and the VMs are
> vmlinuz-2.6.11-xenU. The simulated link is 300Mbps with 80ms RTT.
> Using netperf, I sent data using TCP from domain-0 of machine 1 to
> domain-0 of machine 2. Then I repeat the experiment, but this time
> from VM-1 of machine 1 to VM-1 of machine 2.
>
> However, the performance across the two VMs is substantially worse
> than that across domain-0. Here's the result:
>
> FROM VM to VM:
> TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to dw10.ucsd.edu
> (172.19.222.210) port 0 AF_INET
> Recv Send Send
> Socket Socket Message Elapsed
> Size Size Size Time Throughput
> bytes bytes bytes secs. 10^6bits/sec
>
> 87380 65536 65536 80.28 24.83
>
>
> FROM domain-0 to domain-0:
> TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to damp.ucsd.edu
> (137.110.222.236) port 0 AF_INET
> Recv Send Send
> Socket Socket Message Elapsed
> Size Size Size Time Throughput
> bytes bytes bytes secs. 10^6bits/sec
>
> 87380 65536 65536 80.11 280.62
>
> Here's the setting of the network buffer:
>
> net.core.wmem_max = 8388608
> net.core.rmem_max = 8388608
> net.ipv4.tcp_bic = 1
> net.ipv4.tcp_rmem = 4096 87380 8388608
> net.ipv4.tcp_wmem = 4096 65536 8388608
>
> Does anyone know why the performance across two VMs is so bad? Any fix
> to it? Thank you.
>
> Cherie
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
>
--
"I will not be pushed, filed, stamped, indexed, briefed, debriefed or numbered.
My life is my own."
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