RE: [Xen-users] low network performance

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> funk menera
> Sent: 01 June 2007 13:43
> To: Schmidt, Werner (Werner); xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: RE: [Xen-users] low network performance
> 
> 
> 
> "Schmidt, Werner (Werner)" <wernerschmidt@xxxxxxxxx> schrieb:
> 
>       > -----Original Message-----
>       > From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
>       > [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
>       > funk menera
>       > Sent: 31 May 2007 17:32
>       > To: xen-users@xxxxxxxxxxxxxxxxxxx
>       > Subject: [Xen-users] low network performance
>       > 
>       > Hi @list !
>       > 
>       > This is my first posting so please have patience with
>       > me ;) 
>       > 
>       > As the titel says, i have some problems with the
>       > network performance.
>       > I'm using Xen3.0.3 with Debian on domO and all over
>       > domUs
>       > Maybe the Hardware is interesting too...
>       > AthlonXP 1700+ on MSI.K7T266Pro2 with 1GB RAM, 3
>       > IDE-HDs without RAID and two Networkdevices with
>       > Realtek chipset: 
>       > NIC1: 1GBit r8169 -> for LAN
>       > NIC2: 100MBit 8139 -> for DSL
>       > on the LAN-device is a D-LINK GBit 8-Port Switch
>       > connected.
>       > 
>       > Well i experienced the problems while listening to a
>       > mp3 file on a domU using Samba. Or when extracting
>       > sth. from/to a domU form/to my Laptop. Same for a
>       > transport from domU <-> domU 
>       > Basically it feels laggy or not as fast as i'm used to
>       > (as comparison: the same hardware on a debian-srv
>       > withou XEN) and there are hang-ups
>       > 
>       > 
>       > So a short test with netio shows me sth. like this:
>       > Laptop -> domO         : 11000 KByte/s for Tx and Rx
>       > domO   -> domU-mainsrv : 
>       > TCP connection established.
>       > Packet size  1k bytes:  1870 KByte/s Tx,  12293
>       > KByte/s Rx.
>       > Packet size  2k bytes:  1659 KByte/s Tx,  13503
>       > KByte/s Rx.
>       > Packet size  4k bytes:  1893 KByte/s Tx,  14072
>       > KByte/s Rx.
>       > Packet size  8k bytes:  1869 KByte/s Tx,  16355
>       > KByte/s Rx.
>       > Packet size 16k bytes:  1810 KByte/s Tx,  14836
>       > KByte/s Rx.
>       > Packet size 32k bytes:  1636 KByte/s Tx,  16829
>       > KByte/s Rx.
>       > Done.
>       > 
>       > as i go on 
>       > domU -> domU-efw21(Endian Firewall 2.1):
>       > TCP connection established.
>       > Packet size  1k bytes:  6753 KByte/s Tx,  5481 KByte/s
>       > Rx.
>       > Packet size  2k bytes:  6005 KByte/s Tx,  5532 KByte/s
>       > Rx.
>       > Packet size  4k bytes:  6216 KByte/s Tx,  5271 KByte/s
>       > Rx.
>       > Packet size  8k bytes:  5811 KByte/s Tx,  5491 KByte/s
>       > Rx.
>       > Packet size 16k bytes:  6236 KByte/s Tx,  5603 KByte/s
>       > Rx.
>       > Packet size 32k bytes:  5846 KByte/s Tx,  5588 KByte/s
>       > Rx.
>       > Done.
>       > 
>       > That's terrific if i compare it with the speed which i
>       > had before ... 28MByte/s ~ 50MB/s
>       > 
>       > So i read some pages in the mailing list archive and
>       > found sth. about para-virtual drivers which looked
>       > like it could give me more bandwidth.
>       > Anyhow i just got confused ... 
>       > Is para-virtualsiation meanwhile standard for
>       > Linux-domUs ? 
>       > If not where can i get these drivers ? 
>        
>       > 
>       > Maybe the reason for the low network performance is
>       > somewhere else ?
>        
>        
>       Note that i had similar problems in my tests (I tested 
> the domU and dom0 network performance of multiple machines 
> connected via Gigabit lan with 'iperf ')
>       ;
>       If you use the standard bridge configuration (which I 
> assume is true for your system), you might try to get a 
> better performance by modifying the 'txqueuelen' parameter of 
> the vif devices connecting the domUs to the dom0 bridge 
> ('ifconfig vifx.y' will show the value of this parameter)
>       You can see with  'brctl show' which vifs are involved.
>        
>       In my case, the value was set to '32'
>       I got substantially better results of dom0->domU 
> performance (and domU -> domU performance) by changing this 
> value to 128 ..512:
>       'ip link set vifx.y txqueuelen <value>' will do this 
> change for you
>        
>       Werner
>        
>       _______________________________________________
>       Xen-users mailing list
>       Xen-users@xxxxxxxxxxxxxxxxxxx
>       http://lists.xensource.com/xen-users
>       
> 
> 
> Thanks for the reply.
> But changing the txqueuelen on all doms to 512 dind't bring
> up some performance enhancements on my system.
> Well the value before was a 0 at domO  and 1000 at
>  domUs... what ever that
> means.
> 
> And i'm using the standard bridge-mode to connect the
> doms. But to get sure u may have a look at:
> http://www.neobiker.de/wiki/index.php?title=XEN_Netzwerk_f%C3%
> BCr_Firewall
> because i'm using this script for configuring the
> network.
> But as i understand this script uses bridging ...
> 
> Well, do u also have a one-core CPU, so the problem
> might be comparible to my or do u use a
> dualcore-/quadcore-cpu or dual/quad-system with single
> CPUs ? 
> This point is interesting for me anyway, because in a
> previous mail a Xen-USer told me about that the
> performance would be much better on such a system.
> 
> So therefore i want to ask all of U@list what kind of
> system are u using and how good the performance is? 
> So do u use ...
> a) a antiquated ;) single-core single CPU system as i
> do ? 
> b)
>  'normal' dual singlecore-cpu System ?
> c) 1 dualcore/quadcore cpu ?
> d) more then 1 dualcore/quadcore cpu ? ... maybe 4 of
> them :O ? ... don't wanna know how big the overhead
> might be in this case :X 
> 
> And basically which version would u suggest to run the
> best performance? furthermoire i'd like to know if there is a 
> important performance difference between a AMD or Intel system ?
> 
> Allthough i'm not in the situation (as a poor student)
> to spend some hundred bucks for a new system :( i'm
> interested in that point ... U'll never know where u
> find some money ;) 
> 
> So i just wanna know about the performance to solve my
> question if the system would run as i was used to or
> if there remains some bottlenecks ? 
> Basically i don't need high cpu-power bout a good and
> reliable network and harddisk performance !
> 
> Reagrds,
> fuki
> 
> P.S. Any other hint/tips/link for giving my system
> better performance is highly desired !
>  
> 
> 
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