From: David Miller <davem@davemloft.net>
To: fw@strlen.de
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net-next 0/5] sched: convert queues to single-linked list
Date: Mon, 19 Sep 2016 01:47:44 -0400 (EDT) [thread overview]
Message-ID: <20160919.014744.226583519665969413.davem@davemloft.net> (raw)
In-Reply-To: <1474153054-9059-1-git-send-email-fw@strlen.de>
From: Florian Westphal <fw@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.
prev parent reply other threads:[~2016-09-19 5:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-17 22:57 [PATCH net-next 0/5] sched: convert queues to single-linked list Florian Westphal
2016-09-17 22:57 ` [PATCH net-next 1/5] pie: use qdisc_dequeue_head wrapper Florian Westphal
2016-09-17 22:57 ` [PATCH net-next 2/5] sched: don't use skb queue helpers Florian Westphal
2016-09-17 22:57 ` [PATCH net-next 3/5] sched: remove qdisc arg from __qdisc_dequeue_head Florian Westphal
2016-09-17 22:57 ` [PATCH net-next 4/5] sched: replace __skb_dequeue with __qdisc_dequeue_head Florian Westphal
2016-09-17 22:57 ` [PATCH net-next 5/5] sched: add and use qdisc_skb_head helpers Florian Westphal
2016-09-19 5:47 ` David Miller [this message]
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