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Re: [Xen-users] Slow Network Performance on GPLPV 9.12-pre13

To: James Harper <james.harper@xxxxxxxxxxxxxxxx>
Subject: Re: [Xen-users] Slow Network Performance on GPLPV 9.12-pre13
From: Mark Pace <pace@xxxxxxxxxxxxxxxxxxx>
Date: Thu, 16 Apr 2009 21:53:30 -0700
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> How are you testing performance? And are you measuring from DomU->Dom0
> or DomU->external host?
Copying to and from a SMB share, I've tried the following at this point:

DomU->DomU on same host, speed is good both copying to and from the share.
DomU->External Hosts, copying from the share to the DomU is good,
copying to the share is really slow.

So I tried FTP and SCP instead of SMB traffic:

DomU->DomU on same host, speed is good both directions
DomU->External Host, speed is good both directions

Something strange is afoot...

> If the latter, then your network adapter may not support TCP task
> offload (checksum / large send), although if that was the case I would
> expect that your performance would be kbits not mbits...
Definitely have TCP offload on these machines.  Built in Intel Gigabit
connectors on Supermicro motherboard.

The condition is the same across the three different 2003 DomUs I have
on this host.  I do have another host around that I can move one of
these DomUs onto to see what happens there.


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