From: Florian Westphal <f...@strlen.de>
Date: Sun, 18 Sep 2016 00:57:29 +0200
> During Netfilter Workshop 2016 Eric Dumazet pointed out that qdisc
> schedulers use doubly-linked lists, even though single-linked list
> would be enough.
> The double-linked skb lists incur one extra write on enqueue/dequeue
> operations (to change ->prev pointer of next list elem).
> This series converts qdiscs to single-linked version, listhead
> maintains pointers to first (for dequeue) and last skb (for enqueue).
> Most qdiscs don't queue at all and instead use a leaf qdisc (typically
> pfifo_fast) so only a few schedulers needed changes.
> I briefly tested netem and htb and they seemed fine.
> UDP_STREAM netperf with 64 byte packets via veth+pfifo_fast shows
> a small (~2%) improvement.
Series applied, thanks Florian.