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.
