[ovs-dev] [PATCH 2/2] Raise MAC learning table capacity from 1, 024 to 2, 048 entries per bridge.

Ben Pfaff blp at nicira.com
Sun Sep 13 19:12:08 UTC 2009

Justin Pettit <jpettit at nicira.com> writes:

> On Sep 13, 2009, at 7:47 PM, Ben Pfaff wrote:
>>> Even 2048 entries seems kind of low to me.  Look around on the web,
>>> 8K
>>> entries seems pretty common in hardware switches.  A quick look in
>>> the
>>> kernel sources at the bridge seems to indicate they have no limit
>>> (which is worrying in its own right).
>> Our current implementation of MAC learning statically allocates
>> the entire MAC-learning table at a cost of about 40 kB per table.
>> Doubling the number of entries to 2,048 makes them more like 80
>> kB.  I'm nervous about increasing the limit to 8,192 which would
>> make the cost 320 kB each.  Hence the comment about wanting to
>> switch to dynamic memory allocation if we raise the limit any
>> further.
> Right, I understood that.  My point was that we may want to move more
> aggressively towards that than I felt was conveyed in the commit
> message.  This may be something that we want to do in the master
> branch before too long.

OK, I understand now.

I don't think it would be much work to do this.

More information about the dev mailing list