From: Dave Taht <dave.taht@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>,
"John A. Sullivan III" <jsullivan@opensourcedevel.com>,
netdev@vger.kernel.org
Subject: Re: netem and hierarchical ingress traffic shaping
Date: Fri, 23 Dec 2011 18:54:01 +0100 [thread overview]
Message-ID: <CAA93jw77tL88oxt=2ZTs68k5awCOO2f4d+aE9H-yQdTsd8=gAQ@mail.gmail.com> (raw)
In-Reply-To: <1324661950.4540.20.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>
On Fri, Dec 23, 2011 at 6:39 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le vendredi 23 décembre 2011 à 18:33 +0100, Eric Dumazet a écrit :
>> Le dimanche 18 décembre 2011 à 11:55 -0800, Stephen Hemminger a écrit :
>> > On Sun, 18 Dec 2011 00:12:12 -0500
>> > "John A. Sullivan III" <jsullivan@opensourcedevel.com> wrote:
>> >
>> > > Since netem appears to be classless, we realized we would need to
>> > > replace the SFQ on each leaf with netem which we really didn't want to
>> > > do - not only to not lose SFQ but because we didn't want to maintain the
>> > > netem parameters on each leaf. So, we activated our ifb1 interface,
>> > > placed netem on it and redirected all the egress traffic to ifb1. Taht
>> > > worked fine.
>> >
>> > Current versions of netem can take one class.
>> > --
>>
>> Hmm, I can see that (commit 10f6dfcfde884441)
>>
>> But it wont work very well, it assumes qdisc uses a single queue if
>> netem reordering is requested :
>>
>> (__skb_queue_head(&q->qdisc->q, skb))
>>
>> We should allow reordering if netem queue is changed from tfifo, only if
>> new qdisc is compatible with __skb_queue_head(&q->qdisc->q, skb)
>>
>> (maybe providing a new ->queue_at_head() new ops)
>
> Also, child qdisc must not scratch skb->cb[], since netem stores
> time_to_send in it.
Are there any place where all 48 bytes of cb are used?
I wouldn't mind if 'time_to_send' became a separate skb field
for a more generic 'time_in_queue'...
> I guess nobody actually tried this netem mis-feature :(
>
> I'll send a fix.
>
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Dave Täht
SKYPE: davetaht
US Tel: 1-239-829-5608
FR Tel: 0638645374
http://www.bufferbloat.net
next prev parent reply other threads:[~2011-12-23 17:54 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-18 5:12 netem and hierarchical ingress traffic shaping John A. Sullivan III
2011-12-18 19:55 ` Stephen Hemminger
2011-12-19 16:53 ` John A. Sullivan III
2011-12-23 17:33 ` Eric Dumazet
2011-12-23 17:39 ` Eric Dumazet
2011-12-23 17:54 ` Dave Taht [this message]
2011-12-23 18:28 ` Eric Dumazet
2011-12-23 18:54 ` Dave Taht
2011-12-23 19:07 ` Stephen Hemminger
2011-12-23 19:21 ` Eric Dumazet
2011-12-29 4:26 ` [PATCH net-next] netem: fix classful handling Eric Dumazet
2011-12-29 6:17 ` Stephen Hemminger
2011-12-29 9:12 ` Eric Dumazet
2011-12-29 16:52 ` Hagen Paul Pfeifer
2011-12-29 17:15 ` Eric Dumazet
2011-12-29 17:43 ` Hagen Paul Pfeifer
2011-12-29 18:10 ` Eric Dumazet
2011-12-29 18:25 ` Hagen Paul Pfeifer
2011-12-29 18:31 ` Stephen Hemminger
2011-12-29 18:36 ` Eric Dumazet
2011-12-30 22:12 ` David Miller
2011-12-23 19:36 ` netem and hierarchical ingress traffic shaping David Miller
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='CAA93jw77tL88oxt=2ZTs68k5awCOO2f4d+aE9H-yQdTsd8=gAQ@mail.gmail.com' \
--to=dave.taht@gmail.com \
--cc=eric.dumazet@gmail.com \
--cc=jsullivan@opensourcedevel.com \
--cc=netdev@vger.kernel.org \
--cc=shemminger@vyatta.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).