[altq 577] Re: Running ALTQ

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

Andriy Korud wrote:
> And few more questions:
> 1. What does ALTQ_NOPCC option mean? Will disabling it (using
> processor counters) improve limit resolution?

It requires only one machine cycle to read a processor cycle couner
(timestamp counter for pentium), which is much cheaper than using
microtime().  However, it doesn't affect the kernel timer resolution.

> 2. When CDRN or HFSC are typically used? I saw something about that
> CDRN can limit incoming traffic, is it true? Maybe some references in
> Internet?

CDNR (traffic conditioners) is a set of mechanisms to meter, mark, or
drop incoming traffic.  A good starting point would be RFC2475 (An
Architecture for Differentiated Services).

HFSC (hierachical fair service curve) is a queueing discipline from
CMU.
http://www.cs.cmu.edu/~hzhang/HFSC/main.html

-Kenjiro