ControlMaster and packet stuffing

[Saku Ytti]

When I'm running interactive ssh session which is ControlMaster and I run scp
or sftp to same host, creating another channel, it seems that ssh is stuffing
the packets together exceeding MTU.

I've for years ran QoS where I prioritize small packets, as it is clean and
easy way to guarantee low latency to pretty much all you care for.
Unfortunately ControlMaster packet stuffing breaks this, my interactive packets
are not small anymore for the duration of scp/sftp and receive best effort treatment
making my interactive session extremely laggy.

Is there particular need to combine interactive packets with MTU sized data
packets? In what type of situation is the current behaviour desired?

Thanks,
-- 
  ++ytti