From: Jesper Dangaard Brouer <brouer@redhat.com>
To: John Fastabend <john.fastabend@gmail.com>
Cc: fw@strlen.de, jhs@mojatatu.com, alexei.starovoitov@gmail.com,
eric.dumazet@gmail.com, netdev@vger.kernel.org,
brouer@redhat.com, "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [RFC PATCH v2 08/10] net: sched: pfifo_fast use alf_queue
Date: Fri, 15 Jul 2016 12:09:36 +0200 [thread overview]
Message-ID: <20160715120936.0b339b2a@redhat.com> (raw)
In-Reply-To: <578829C7.8060604@gmail.com>
On Thu, 14 Jul 2016 17:09:43 -0700
John Fastabend <john.fastabend@gmail.com> wrote:
> >> static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
> >> struct sk_buff **to_free)
> >> {
> >> - if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
> >> - int band = prio2band[skb->priority & TC_PRIO_MAX];
> >> - struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
> >> - struct sk_buff_head *list = band2list(priv, band);
> >> -
> >> - priv->bitmap |= (1 << band);
> >> - qdisc->q.qlen++;
> >> - return __qdisc_enqueue_tail(skb, qdisc, list);
> >> - }
> >> + int band = prio2band[skb->priority & TC_PRIO_MAX];
> >> + struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
> >> + struct skb_array *q = band2list(priv, band);
> >> + int err;
> >>
> >> - return qdisc_drop(skb, qdisc, to_free);
> >> + err = skb_array_produce_bh(q, skb);
> >
> > Do you need the _bh variant here? (Doesn't the qdisc run with BH disabled?)
> >
> >
>
> Yep its inside rcu_read_lock_bh().
The call rcu_read_lock_bh() already disabled BH (local_bh_disable()).
Thus, you can use the normal variants of skb_array_produce(), it is
(approx 20 cycles) faster than the _bh variant...
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2016-07-15 10:09 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-14 6:19 [RFC PATCH v2 00/10] running qdiscs without qdisc_lock John Fastabend
2016-07-14 6:19 ` [RFC PATCH v2 01/10] net: sched: allow qdiscs to handle locking John Fastabend
2016-07-14 6:44 ` John Fastabend
2016-07-14 6:20 ` [RFC PATCH v2 02/10] net: sched: qdisc_qlen for per cpu logic John Fastabend
2016-07-14 6:20 ` [RFC PATCH v2 03/10] net: sched: provide per cpu qstat helpers John Fastabend
2016-07-14 6:21 ` [RFC PATCH v2 04/10] net: sched: a dflt qdisc may be used with per cpu stats John Fastabend
2016-07-14 6:21 ` [RFC PATCH v2 05/10] net: sched: per cpu gso handlers John Fastabend
2016-07-14 6:22 ` [RFC PATCH v2 06/10] net: sched: support qdisc_reset on NOLOCK qdisc John Fastabend
2016-07-14 6:22 ` [RFC PATCH v2 07/10] net: sched: support skb_bad_tx with lockless qdisc John Fastabend
2016-07-14 6:23 ` [RFC PATCH v2 08/10] net: sched: pfifo_fast use alf_queue John Fastabend
2016-07-14 15:11 ` Jesper Dangaard Brouer
2016-07-15 0:09 ` John Fastabend
2016-07-15 10:09 ` Jesper Dangaard Brouer [this message]
2016-07-15 17:29 ` John Fastabend
2016-07-14 23:42 ` Alexei Starovoitov
2016-07-15 0:07 ` John Fastabend
2016-07-15 11:23 ` Jesper Dangaard Brouer
2016-07-15 22:18 ` John Fastabend
2016-07-15 22:48 ` Alexei Starovoitov
2016-07-14 6:23 ` [RFC PATCH v2 09/10] net: sched: helper to sum qlen John Fastabend
2016-07-14 6:24 ` [RFC PATCH v2 10/10] net: sched: add support for TCQ_F_NOLOCK subqueues to sch_mq John Fastabend
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160715120936.0b339b2a@redhat.com \
--to=brouer@redhat.com \
--cc=alexei.starovoitov@gmail.com \
--cc=eric.dumazet@gmail.com \
--cc=fw@strlen.de \
--cc=jhs@mojatatu.com \
--cc=john.fastabend@gmail.com \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.