Re: ALTQ cbq(efficient) in OpenBSD 3.3

[Kenjiro Cho <kjc@csl.sony.co.jp>]

Mark Bojara wrote:
> Ive set up OpenBSD to run ALTQ and it works very nice (alot better than
> freebsd.. but freebsd is still be prefered OS). With ALTQ on FreeBSD I
> could use the option efficient wich when I enabled this option it would be
> able to use full bandwidth from its parent if borrowing was enabled.

The "efficient" option is a hack added by Sun to make CBQ
work-conserving, where CBQ sends packets as long as it has
back-logged packets even when all classes are not eligible to send
packets.

The problem of this option is that CBQ picks up an arbitrary class.
As a result, it is impossible to predict the behavior.
I don't intend to re-enable this option in OpenBSD since it is just
another confusing knob for average admin users.

Having said that, the API for this option is already there so that,
if you add 2 lines to pfctl/parse.y to accept the "efficient" keyword,
it should just work.

HFSC (only available post-3.3 snapshots) does much better than CBQ
in distibuting available bandwidth.
So, you might want to give it a try.

-Kenjiro