Re: [Xen-users] Good unidirectional TCP performance, weird asymetric performance going bidirectional

["Dr. Volker Jaenisch" <volker.jaenisch@xxxxxxxxx>]

Hi Pasi!

THanks for the fast reply!

Pasi Kärkkäinen schrieb:
> On Mon, Sep 22, 2008 at 11:11:37AM +0300, Pasi Kärkkäinen wrote:
>   
>> Have you tried changing the vif* interface txqueuelen in dom? I'm wondering
>> if that would help..
>>     
Yes I did. I changed the txqueulength from 0 (yes ifconfig shows me
ZERO) to 1000.
Should I change the txqueulength of the bridge too?

zeus:~# ifconfig
br0       Link encap:Ethernet  HWaddr 00:1B:FC:DB:D2:79
          inet addr:192.168.2.20  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::21b:fcff:fedb:d279/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2758816 errors:0 dropped:0 overruns:0 frame:0
          TX packets:831349 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:3711167604 (3.4 GiB)  TX bytes:861930334 (822.0 MiB)

eth0      Link encap:Ethernet  HWaddr 00:1B:FC:DB:D2:79
          inet6 addr: fe80::21b:fcff:fedb:d279/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1333 errors:0 dropped:0 overruns:0 frame:0
          TX packets:908 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:178350 (174.1 KiB)  TX bytes:124770 (121.8 KiB)
          Interrupt:23

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:34 errors:0 dropped:0 overruns:0 frame:0
          TX packets:34 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:2576 (2.5 KiB)  TX bytes:2576 (2.5 KiB)

vif2.0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF
          inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2757485 errors:0 dropped:0 overruns:0 frame:0
          TX packets:829015 errors:0 dropped:1588 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3711013112 (3.4 GiB)  TX bytes:860609840 (820.7 MiB)


Did no change at all (txqueuelength of vif and br0 changed to 1000):

apollo2:~#
dom0 <=> domU

iperf -c 192.168.2.20 -p5555 -t5
------------------------------------------------------------
Client connecting to 192.168.2.20, TCP port 5555
TCP window size: 23.3 KByte (default)
------------------------------------------------------------
[  3] local 192.168.2.22 port 39015 connected with 192.168.2.20 port 5555
[  3]  0.0- 5.0 sec    788 MBytes  1.32 Gbits/sec
apollo2:~# iperf -c 192.168.2.20 -p5555 -t5 -d
------------------------------------------------------------
Server listening on TCP port 5555
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.2.20, TCP port 5555
TCP window size: 77.7 KByte (default)
------------------------------------------------------------
[  5] local 192.168.2.22 port 39016 connected with 192.168.2.20 port 5555
[  4] local 192.168.2.22 port 5555 connected with 192.168.2.20 port 48509
[  5]  0.0- 5.0 sec    894 MBytes  1.50 Gbits/sec
[  4]  0.0- 5.1 sec  25.3 MBytes  41.4 Mbits/sec

domU <=> dom0

apollo2:~# iperf -s  -p5555
------------------------------------------------------------
Server listening on TCP port 5555
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 192.168.2.22 port 5555 connected with 192.168.2.20 port 59129
------------------------------------------------------------
Client connecting to 192.168.2.20, TCP port 5555
TCP window size: 38.8 KByte (default)
------------------------------------------------------------
[  6] local 192.168.2.22 port 39017 connected with 192.168.2.20 port 5555
[  6]  0.0-10.0 sec  1.68 GBytes  1.44 Gbits/sec
[  4]  0.0-10.0 sec  40.3 MBytes  33.8 Mbits/sec

dom0 -> domU

[  5] local 192.168.2.22 port 5555 connected with 192.168.2.20 port 59130
[  5]  0.0-10.0 sec    703 MBytes    590 Mbits/sec

In openVZ the txqueuelength is also 0 and the bidirectional transfer
rate is not asymetric.

Any other ideas?

Best Regards

Volker

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