[ovs-dev] [PATCH 4/4] datapath: Add module parameter to allow TSO with vlans.

Jesse Gross jesse at nicira.com
Mon Feb 7 20:45:31 UTC 2011

On Mon, Feb 7, 2011 at 11:04 AM, Ben Pfaff <blp at nicira.com> wrote:
> On Sat, Feb 05, 2011 at 04:14:49PM -0800, Jesse Gross wrote:
>> We currently perform GSO on packets before adding a vlan tag,
>> which is reliable but hurts performance.  Even NICs that support
>> TSO on vlan tagged packets typically expect vlan acceleration to
>> be used.  Before 2.6.37 we can't use vlan acceleration and must
>> place the tag in the packet itself, which is risky when used with
>> TSO.  However, if the driver is known to work with internally
>> tagged packets and TSO this exposes a module parameter to enable it.
>> Signed-off-by: Jesse Gross <jesse at nicira.com>
> Oh, one more thing: we should document this module parameter somewhere,
> if only in INSTALL.Linux.

I added a note to INSTALL.Linux.  It's not something that I want to
widely publicize because it really requires knowing what's going on to
use correctly.

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