Development issues regarding the cerowrt test router project
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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: "Toke Høiland-Jørgensen" <toke@toke.dk>
Cc: Paolo Valente <paolo.valente@unimore.it>,
	Eric Raymond <esr@thyrsus.com>,
	"codel@lists.bufferbloat.net" <codel@lists.bufferbloat.net>,
	"cerowrt-devel@lists.bufferbloat.net"
	<cerowrt-devel@lists.bufferbloat.net>,
	bloat <bloat@lists.bufferbloat.net>,
	David Woodhouse <dwmw2@infradead.org>,
	John Crispin <blogic@openwrt.org>
Subject: Re: [Cerowrt-devel] FQ_Codel lwn draft article review
Date: Mon, 3 Dec 2012 06:58:49 -0800	[thread overview]
Message-ID: <20121203145849.GH2605@linux.vnet.ibm.com> (raw)
In-Reply-To: <87fw3n5m9g.fsf@toke.dk>

On Mon, Dec 03, 2012 at 01:54:35PM +0100, Toke Høiland-Jørgensen wrote:
> Dave Taht <dave.taht@gmail.com> writes:
> 
> > you have no control. The tx queue rings are flooded before control is
> > handed back to the fq_codel scheduler. You can get some control back
> > on a non-BQL driver by reducing the number of tx descriptors
> > dramatically, but that leads to issues with small vs big packets....
> 
> Right, so BQL is pretty much a requirement to get anything worthwhile
> out of fq_codel? Or is that too strongly put?

If I understand the code correctly, without BQL, FQ-CoDel does not get
invoked at all.

							Thanx, Paul

> Without BQL, exactly how much does the driver queue up? I've heard
> someone say 1000 packets for ethernet, but is that in a different
> context? E.g. pfifo_fast uses /sys/class/net/*/tx_queue_len for queue
> length (I think?), but if the qdisc doesn't, does the driver?
> 
> -Toke
> 
> -- 
> Toke Høiland-Jørgensen
> toke@toke.dk



  reply	other threads:[~2012-12-03 15:08 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAA93jw5yFvrOyXu2s2DY3oK_0v3OaNfnL+1zTteJodfxtAAzcQ@mail.gmail.com>
2012-11-23  8:57 ` Dave Taht
2012-11-23 22:18   ` Paul E. McKenney
2012-11-24  0:07     ` Toke Høiland-Jørgensen
2012-11-24 16:19       ` Dave Taht
2012-11-24 16:36         ` dpreed
2012-11-24 19:57         ` [Cerowrt-devel] [Codel] " Andrew McGregor
2012-11-26 21:13         ` Rick Jones
2012-11-26 21:19           ` Dave Taht
2012-11-26 22:16         ` [Cerowrt-devel] " Toke Høiland-Jørgensen
2012-11-26 23:21           ` Toke Høiland-Jørgensen
2012-11-26 23:39             ` dpreed
2012-11-26 23:58               ` Toke Høiland-Jørgensen
2012-11-26 17:20       ` Paul E. McKenney
2012-11-26 21:05       ` [Cerowrt-devel] [Codel] " Rick Jones
2012-11-26 23:18         ` [Cerowrt-devel] [Bloat] " Rick Jones
2012-11-27 22:03     ` [Cerowrt-devel] " Jim Gettys
2012-11-27 22:31       ` [Cerowrt-devel] [Bloat] " David Lang
2012-11-27 22:54         ` Paul E. McKenney
2012-11-27 23:15           ` [Cerowrt-devel] [Codel] " Andrew McGregor
2012-11-28  0:51             ` Paul E. McKenney
2012-11-28 17:36             ` Paul E. McKenney
2012-11-28 14:06         ` [Cerowrt-devel] " Michael Richardson
2012-11-27 22:49       ` [Cerowrt-devel] " Paul E. McKenney
2012-11-27 23:53         ` [Cerowrt-devel] [Codel] " Greg White
2012-11-28  0:27           ` Paul E. McKenney
2012-11-28  3:43             ` Kathleen Nichols
2012-11-28  4:38               ` Paul E. McKenney
2012-11-28 16:01                 ` Paul E. McKenney
2012-11-28 16:16                   ` Jonathan Morton
2012-11-28 17:44                     ` Paul E. McKenney
2012-11-28 18:37                       ` [Cerowrt-devel] [Bloat] " Michael Richardson
2012-11-28 18:51                         ` [Cerowrt-devel] [Codel] [Bloat] " Eric Dumazet
2012-11-28 21:44                           ` Michael Richardson
2012-11-28 19:00                       ` [Cerowrt-devel] [Bloat] [Codel] " Eric Dumazet
2012-12-02 21:37                         ` Toke Høiland-Jørgensen
2012-12-02 21:47                           ` [Cerowrt-devel] [Codel] [Bloat] " Andrew McGregor
2012-12-03  8:04                             ` [Cerowrt-devel] [Bloat] [Codel] " Dave Taht
2012-12-02 22:07                           ` Eric Dumazet
2012-12-02 22:15                             ` Toke Høiland-Jørgensen
2012-12-02 22:30                               ` Eric Dumazet
2012-12-02 22:51                                 ` Toke Høiland-Jørgensen
2012-11-28 17:20       ` [Cerowrt-devel] " Paul E. McKenney
2012-12-02 23:06         ` Paul E. McKenney
2012-12-03 11:24           ` Toke Høiland-Jørgensen
2012-12-03 11:31             ` Dave Taht
2012-12-03 12:54               ` Toke Høiland-Jørgensen
2012-12-03 14:58                 ` Paul E. McKenney [this message]
2012-12-03 15:19                   ` Toke Høiland-Jørgensen
2012-12-03 15:49                   ` [Cerowrt-devel] [Codel] " Eric Dumazet
2012-12-03 15:03               ` [Cerowrt-devel] " Paul E. McKenney
2012-12-03 15:58               ` David Woodhouse
2012-12-04  3:13                 ` [Cerowrt-devel] [Codel] " Dan Siemon
2012-12-04  9:23                   ` [Cerowrt-devel] [Bloat] " Alex Burr
2012-12-05  3:41                     ` Dan Siemon
     [not found]                       ` <1354739624.4431.YahooMailNeo@web126205.mail.ne1.yahoo.com>
2012-12-06  4:12                         ` Dan Siemon
2012-12-05  0:01                   ` [Cerowrt-devel] " Sebastian Moeller
2012-11-30  1:09       ` [Cerowrt-devel] [Bloat] " Dan Siemon

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