[Codel] Floating an Idea. ip_fq_codel

Eric Dumazet eric.dumazet at gmail.com
Tue May 20 11:38:47 EDT 2014

On Tue, 2014-05-20 at 08:31 -0700, Eric Dumazet wrote:
> On Tue, 2014-05-20 at 20:16 +1000, Andrew McGregor wrote:
> > That's about what constitutes a flow.  fq_codel as implemented in
> > linux works per (source ip, dest ip, protocol, source port, dest port)
> > 5-tuple.  Linux should probably support multiple flow hashing
> > algorithms in the kernel.
> > 
> Right. fq_codel uses the same trick than other qdisc, like SFQ
> By _default_ it uses a 5-tuple hash. Thats convenient but not a
> requirement.
> You can classify packets using a filter and for example hash only on the
> part you need. For example destination IP, or source IP, depending if
> you use fq_codel on egress or ingress sides.
> tc qdisc add dev eth0 root handle 1: fq_codel flows 8192
> tc filter add dev eth0 protocol ip parent 1: handle 1 \
> 	flow hash keys dst divisor 8192

Btw, while fq_codel can have 'flows xxx'  with any value for xxx,
the filter part requires 'divisor power_of_two', because it uses a AND
operation, not a MODULO.

So I doubt the filter at line 63 of http://pastebin.com/hXtzFL9f 
has any chance working. It probably is not installed.

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