> -----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
