Xen users - Feb 2008 - nic poor performance after upgrade to xen 3.2

Hi,
I''m doing some test on a network 10 gb nics and xen
with version 3.1 i''m measuring 2.5 gb/sec from domU to an external
physical machine with iperf.
switching to 3.2 has reduced the measured performance to 40-50 Mb/sec.

did anything change in the network interface?

can someone help me?

thanks

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I think you use netfront to achieve such performances on domU
so you have to recompile in unmodified_drivers/linux-2.6  from Xen 
sources under your domU
and load the kernel modules at boot time

xen-vnif.ko xen-platform-pci.ko xen-vbd.ko xen-balloon.ko

you must alias eth0 xen-vnif in modprobe.conf and of couse use netfront 
instead of ioemu
in the vif part of your guest config file. But I think this step is 
already done on your guest
otherwise you cannot achieve such a speed with vif type set to ioemu.

Riccardo




Omar Schiaratura ha scritto:
> Hi,
> I''m doing some test on a network 10 gb nics and xen
> with version 3.1 i''m measuring 2.5 gb/sec from domU to an external
physical machine with iperf.
> switching to 3.2 has reduced the measured performance to 40-50 Mb/sec.
>
> did anything change in the network interface?
>
> can someone help me?
>
> thanks
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>   

_______________________________________________
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place "sysctl -p" as the first line in the /etc/init.d/netfs right
after the
first stanza of comments.

try these changes to the /etc/sysctl.conf file on the Guests
(for the host, the last line, sunrpc, is not available, so remove it)

net.core.netdev_max_backlog = 30000
net.core.rmem_default = 256960
net.core.rmem_max = 16777216
net.core.wmem_default = 256960
net.core.wmem_max = 16777216
net.core.rmem_default = 65536
net.core.wmem_default = 65536
net.core.rmem_max = 8388608
net.core.wmem_max = 8388608
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 16384 4194304
net.ipv4.tcp_mem = 4096 4096 4096
sunrpc.tcp_slot_table_entries = 128

On Feb 6, 2008 11:27 AM, Riccardo Veraldi <Riccardo.Veraldi@cnaf.infn.it>
wrote:
>
> I think you use netfront to achieve such performances on domU
> so you have to recompile in unmodified_drivers/linux-2.6  from Xen
> sources under your domU
> and load the kernel modules at boot time
>
> xen-vnif.ko xen-platform-pci.ko xen-vbd.ko xen-balloon.ko
>
> you must alias eth0 xen-vnif in modprobe.conf and of couse use netfront
> instead of ioemu
> in the vif part of your guest config file. But I think this step is
> already done on your guest
> otherwise you cannot achieve such a speed with vif type set to ioemu.
>
> Riccardo
>
>
>
>
> Omar Schiaratura ha scritto:
> > Hi,
> > I''m doing some test on a network 10 gb nics and xen
> > with version 3.1 i''m measuring 2.5 gb/sec from domU to an
external
> physical machine with iperf.
> > switching to 3.2 has reduced the measured performance to 40-50 Mb/sec.
> >
> > did anything change in the network interface?
> >
> > can someone help me?
> >
> > thanks
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@lists.xensource.com
> > http://lists.xensource.com/xen-users
> >
>
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>


-- 
--tmac

RedHat Certified Engineer #804006984323821 (RHEL4)
RedHat Certified Engineer #805007643429572 (RHEL5)

Principal Consultant, RABA Technologies


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I think this solution is usefull if you have a full virtualization environment,
in my case i used a xenolinux kernel in domU, so i already had the
paravirtualized network driver.
when i use my sun nxge 10Gb nic i reached a poor performance of up to 50 Mb/s.
Using another nic suc as a 100 Mb or 1Gb ethernet, the performance reached the
maximum bandwidth of (respectively) 100 M/s or 1Gb/s


 
Alle mercoledì 6 febbraio 2008, Riccardo Veraldi ha
scritto:
> 
> I think you use netfront to achieve such performances on domU
> so you have to recompile in unmodified_drivers/linux-2.6  from Xen 
> sources under your domU
> and load the kernel modules at boot time
> 
> xen-vnif.ko xen-platform-pci.ko xen-vbd.ko xen-balloon.ko
> 
> you must alias eth0 xen-vnif in modprobe.conf and of couse use netfront 
> instead of ioemu
> in the vif part of your guest config file. But I think this step is 
> already done on your guest
> otherwise you cannot achieve such a speed with vif type set to ioemu.
> 
> Riccardo
> 
> 
> 
> 
> Omar Schiaratura ha scritto:
> > Hi,
> > I''m doing some test on a network 10 gb nics and xen
> > with version 3.1 i''m measuring 2.5 gb/sec from domU to an
external physical machine with iperf.
> > switching to 3.2 has reduced the measured performance to 40-50 Mb/sec.
> >
> > did anything change in the network interface?
> >
> > can someone help me?
> >
> > thanks
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@lists.xensource.com
> > http://lists.xensource.com/xen-users
> >   
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 


-- 
_____________________________________
Ing. Omar Schiaratura
Dottore in Scienze dell''Informazione

Expert software Engineer
Distribuited Computing group - CRS4
Email: omar@crs4.it
http://www.crs4.it/
http://www.omarschiaratura.it/
Tel.: +39 070 9250 286
Cell.: +39 328 3061860
_____________________________________

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