From: "John W. Linville" <linville@tuxdriver.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>,
Albert Cahalan <acahalan@gmail.com>,
Mikael Abrahamsson <swmike@swm.pp.se>,
linux-kernel <linux-kernel@vger.kernel.org>,
netdev@vger.kernel.org
Subject: Re: txqueuelen has wrong units; should be time
Date: Mon, 28 Feb 2011 11:55:01 -0500 [thread overview]
Message-ID: <20110228165501.GC2515@tuxdriver.com> (raw)
In-Reply-To: <1298911694.2941.639.camel@edumazet-laptop>
On Mon, Feb 28, 2011 at 05:48:14PM +0100, Eric Dumazet wrote:
> Le lundi 28 février 2011 à 11:11 -0500, John W. Linville a écrit :
> > On Sun, Feb 27, 2011 at 09:07:53PM +0100, Eric Dumazet wrote:
> >
> > > Qdisc should return to caller a good indication packet is queued or
> > > dropped at enqueue() time... not later (aka : never)
> > >
> > > Accepting a packet at t0, and dropping it later at t0+limit without
> > > giving any indication to caller is a problem.
> >
> > Can you elaborate on what problem this causes? Is it any worse than
> > if the packet is dropped at some later hop?
> >
> > Is there any API that could report the drop to the sender (at
> > least a local one) without having to wait for the ack timeout?
> > Should there be?
> >
>
> Not all protocols have ACKS ;)
>
> dev_queue_xmit() returns an error code, some callers use it.
Well, OK -- I agree it is best if you can return the status at
enqueue time. The question becomes whether or not a dropped frame
is worse than living with high latency. The answer, of course, still
seems to be a bit subjective. But, if the admin has determined that
a link should be low latency...?
John
--
John W. Linville Someday the world will need a hero, and you
linville@tuxdriver.com might be all we have. Be ready.
next prev parent reply other threads:[~2011-02-28 16:55 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-27 5:44 txqueuelen has wrong units; should be time Albert Cahalan
2011-02-27 7:02 ` Mikael Abrahamsson
2011-02-27 7:54 ` Eric Dumazet
2011-02-27 8:27 ` Albert Cahalan
2011-02-27 10:55 ` Jussi Kivilinna
2011-02-27 20:07 ` Eric Dumazet
2011-02-27 21:32 ` Jussi Kivilinna
2011-02-28 11:43 ` Jussi Kivilinna
2011-02-28 13:10 ` Eric Dumazet
2011-02-28 18:31 ` Jussi Kivilinna
2011-02-28 16:11 ` John W. Linville
2011-02-28 16:48 ` Eric Dumazet
2011-02-28 16:55 ` John W. Linville [this message]
2011-02-28 17:18 ` Eric Dumazet
2011-02-28 21:45 ` John Heffner
2011-03-01 4:11 ` Albert Cahalan
2011-03-01 4:18 ` David Miller
2011-03-01 6:54 ` Albert Cahalan
2011-03-01 7:25 ` David Miller
2011-03-01 7:26 ` Eric Dumazet
2011-03-01 19:37 ` Albert Cahalan
2011-03-01 20:14 ` Eric Dumazet
2011-03-01 20:16 ` Eric Dumazet
2011-03-02 3:10 ` Mikael Abrahamsson
2011-03-02 20:25 ` Chris Friesen
2011-03-01 5:01 ` Eric Dumazet
2011-03-01 5:36 ` Eric Dumazet
2011-02-27 23:33 ` Albert Cahalan
2011-02-28 11:23 ` Jussi Kivilinna
2011-03-02 21:54 ` [RFC LOL OMG] pfifo_lat: qdisc that limits dequeueing based on estimated link latency John W. Linville
2011-03-02 22:08 ` John W. Linville
2011-03-03 12:51 ` Eric Dumazet
2011-02-28 15:38 ` txqueuelen has wrong units; should be time Hagen Paul Pfeifer
2011-02-28 16:37 ` Albert Cahalan
2011-02-28 17:45 ` John W. Linville
2011-02-28 17:20 ` Bill Sommerfeld
2011-02-28 21:51 ` John Heffner
2011-03-01 0:46 ` Mikael Abrahamsson
2011-03-02 6:25 ` Stephen Hemminger
2011-03-02 6:41 ` Mikael Abrahamsson
2011-03-02 7:07 ` Stephen Hemminger
2011-03-02 16:41 ` Mikael Abrahamsson
2011-03-02 16:50 ` Eric Dumazet
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=20110228165501.GC2515@tuxdriver.com \
--to=linville@tuxdriver.com \
--cc=acahalan@gmail.com \
--cc=eric.dumazet@gmail.com \
--cc=jussi.kivilinna@mbnet.fi \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=swmike@swm.pp.se \
/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).