[rabbitmq-discuss] MTU

Mon May 10 09:18:04 BST 2010

On Sun, 09 May 2010 11:26:14 +0100, David Wragg wrote:

> <holger.hoffstaette at googlemail.com> writes:
>>
>> It is certainly possible and not at all unusual for network software to
>> observe the MTU of a given interface (via an ioctl) and use it
>> accordingly. The most obvious use case for Rabbit would be batching of
>> small messages, where every payload is just a few bytes. This would
> 
> What you describe sounds more like the use of corking (e.g. via the
> TCP_CORK ioctl in Linux) than an interaction with the MTU.

Sort of, kind of - but the point is to do this in userspace, not in the
TCP stack. Otherwise you could just re-enable Nagle.

> I see that the linux ip(7) and tcp(7) man pages do indeed describe some
> MTU/MSS related options, so my statement was too strong.  I should have
> said that RabbitMQ does nothing to observe or control the MTU.  But it

Right, and that is really all I was saying. Trying to change the MTU for a
regular app is IMHO straight from the "not even wrong" category.

cheers
Holger