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Xenserver 7 - Slow network throughput in guest OS (Windows 7 x64)

Started by Chris Shaw , 16 February 2017 - 09:51 AM
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Chris Shaw Members

Chris Shaw
  • 1 posts

Posted 16 February 2017 - 09:51 AM

Hi,

 

I wonder if anyone can offer any advice please?

 

I've been pulling my hair out trying to figure this one out, but so far, not so good!

 

I'm using NetIO to measure the throughput between Xenserver hosts and all appears acceptable. In this example the two Xenservers are connected to the same switch on a 1Gb connection. These are the results:

 

NETIO - Network Throughput Benchmark, Version 1.31
© 1997-2010 Kai Uwe Rommel
 
TCP connection established.
Packet size  1k bytes:  38.87 MByte/s Tx,  94.08 MByte/s Rx.
Packet size  2k bytes:  65.34 MByte/s Tx,  109.28 MByte/s Rx.
Packet size  4k bytes:  107.04 MByte/s Tx,  111.36 MByte/s Rx.
Packet size  8k bytes:  106.92 MByte/s Tx,  111.07 MByte/s Rx.
Packet size 16k bytes:  110.42 MByte/s Tx,  98.89 MByte/s Rx.
Packet size 32k bytes:  106.46 MByte/s Tx,  110.67 MByte/s Rx.
Done.

 

However, if I run the same test from a Windows 7 VM on the same host, I get these results:

 

NETIO - Network Throughput Benchmark, Version 1.32
© 1997-2012 Kai Uwe Rommel
 
TCP connection established.
Packet size  1k bytes:  27.78 MByte/s Tx,  25.06 MByte/s Rx.
Packet size  2k bytes:  32.24 MByte/s Tx,  25.76 MByte/s Rx.
Packet size  4k bytes:  36.82 MByte/s Tx,  25.24 MByte/s Rx.
Packet size  8k bytes:  42.33 MByte/s Tx,  26.59 MByte/s Rx.
Packet size 16k bytes:  47.01 MByte/s Tx,  27.28 MByte/s Rx.
Packet size 32k bytes:  45.50 MByte/s Tx,  30.75 MByte/s Rx.
Done.

 

 

Things I've tried so far:

 

Disabled checksumming on eth0 on the Xenserver:

 

Disabled checksumming on all of the VIFs on the Xenserver.

Rebooted the Xenserver

 

Disabled TaskOffload on the Windows VM

 

Disabled TCPChimney on the Windows VM

 

Disabled all of the offload setting in the Windows VM PV Network adapter.

 

The network adapter in the host is a Broadcom NetExtreme BCM5720

 

Any advice would be most appreciated.

 

Thanks,

​Chris

 



Alan Lantz Members

Alan Lantz
  • 6,685 posts

Posted 16 February 2017 - 10:55 PM

I would expect to see a little more as well. Most VM's would still run just fine under these conditions. But I am like you and would be curious to know why. I haven't done benchmarking lately, been overwhelmed with other duties. Just the typical questions about hardware on HCL, firmware up to date as well as XenServer and all hotfixes. 

 

--Alan--