Re: [PATCH] Allow TSO to be disabled for forcedeth driver
From: Zachary Amsden
Date: Thu Jun 01 2006 - 16:06:26 EST
Andrew Morton wrote:
Zachary Amsden <zach@xxxxxxxxxx> wrote:
TSO can cause performance problems in certain environments, and being
able to turn it on or off is helpful for debugging network issues. Most
other network drivers that support TSO allow it to be toggled, so add
this feature to forcedeth. Tested by Harald Dunkel, who reported that
this fixed his network performance issue with VMware.
(This is regarding
http://www.vmware.com/community/thread.jspa?messageID=408893)
Why does TSO-with-forcedeth make vmware networking slow?
Is it specific to the forcedeth driver?
No. TSO is not good for bridged virtual networking in general, since
even if the bridged networking module understood TSO, it would then have
to split up any large packets into smaller packets to pass on to the
guest virtual machine - or require that the guest virtual machine have
and understand how to use a TSO compatible network interface as well.
Both solutions are extremely problematic, and the easiest thing to do is
just disable TSO. It makes sense for any protocol bridge device,
including some firewall configurations.
Zach
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