RE: [Xen-users] low network performance

Petersson, Mats
2007-06-01T13:19:23Z

> Sent: 01 June 2007 13:43
> To: Schmidt, Werner (Werner); xen-users@lists.xensource.com
> Subject: RE: [Xen-users] low network performance
>
>
>
> "Schmidt, Werner (Werner)" <wernerschmidt@avaya.com>
schrieb:
>
> 	> -----Original Message-----
> 	> From: xen-users-bounces@lists.xensource.com
> 	> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of
> 	> funk menera
> 	> Sent: 31 May 2007 17:32
> 	> To: xen-users@lists.xensource.com
> 	> 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@lists.xensource.com
> 	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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